Article

Calculation of free and bound fractions of testosterone and estradiol-17?? to human plasma proteins at body temperature

July 1982
Journal of Steroid Biochemistry 16(6):801-10

Source
PubMed

Authors:

Umeå University

A mathematical model for the calculation of free and protein bound concentrations of testosterone and estradiol in plasma is presented. The method is based on the knowledge of the total concentrations of all steroids competing for the same binding site on testosterone-estradiol-binding globulin (TeBG), the concentration of albumin, the binding capacity of TeBG, and the association constants of the steroids to the two binding proteins. For the calculations we have determined the total concentrations of testosterone and estradiol. TeBG binding capacity, albumin concentration and the association constants for the binding of testosterone, estradiol and 5 alpha-dihydrotestosterone (DHT) to TeBG and albumin at 37 degrees C. Physiological concentrations of some androgen metabolites reported in the literature were also included in the calculations, namely: DHT, 5-androstene-3 beta, 17 beta-diol (Ae) and 5 alpha-androstane-3 alpha, 17 beta-diol (Aa). The binding constants for Ae and Aa to TeBG and albumin were also from the literature. Mean values of testosterone were calculated for 11 normal men and expressed as percentages of total: 2.0% was unbound, 53--55% bound to albumin and 43--45% bound to TeBG. For 16 normal women of a fertile age the corresponding values were 1.5%, 36--37% and 62%. For estradiol they were 2.4% 68--70% and 28--30% in the men and 2.0%, 52% and 45--46% in the women. Variations in the concentrations of DHT. Ae and Aa did not influence the free concentrations of testosterone and estradiol to any significant extent. It was furthermore concluded that the androgen metabolites could be omitted from the calculations without affecting the calculated concentrations.

Higher testosterone and testosterone/estradiol ratio in men are associated with decreased Pheno-/GrimAge and DNA-methylation based PAI1

Article

Full-text available

Jun 2023

Sex hormones are hypothesized to drive sex-specific health disparities. Here, we study the association between sex steroid hormones and DNA methylation-based (DNAm) biomarkers of age and mortality risk including Pheno Age Acceleration (AA), Grim AA, and DNAm-based estimators of Plasminogen Activator Inhibitor 1 (PAI1), and leptin concentrations. We pooled data from three population-based cohorts, the Framingham Heart Study Offspring Cohort, the Baltimore Longitudinal Study of Aging, and the InCHIANTI Study, including 1,062 postmenopausal women without hormone therapy and 1,612 men of European descent. Sex-stratified analyses using a linear mixed regression were performed, with a Benjamini-Hochberg (BH) adjustment for multiple testing. Sex Hormone Binding Globulin (SHBG) was associated with a decrease in DNAm PAI1 among men (per 1 standard deviation (SD): -478 pg/mL; 95%CI: -614 to -343; P:1e-11; BH-P: 1e-10), and women (-434 pg/mL; 95%CI: -589 to -279; P:1e-7; BH-P:2e-6). The testosterone/estradiol (TE) ratio was associated with a decrease in Pheno AA (-0.41 years; 95%CI: -0.70 to -0.12; P:0.01; BH-P: 0.04), and DNAm PAI1 (-351 pg/mL; 95%CI: -486 to -217; P:4e-7; BH-P:3e-6) among men. In men, testosterone was associated with a decrease in DNAm PAI1 (-481 pg/mL; 95%CI: -613 to -349; P:2e-12; BH-P:6e-11). SHBG was associated with lower DNAm PAI1 among men and women. Higher testosterone and testosterone/estradiol ratio were associated with lower DNAm PAI and a younger epigenetic age in men. A decrease in DNAm PAI1 is associated with lower mortality and morbidity risk indicating a potential protective effect of testosterone on lifespan and conceivably cardiovascular health via DNAm PAI1. Graphical Abstract

Endogenous Sex Hormone Levels and Myocardial Fibrosis in Men and Postmenopausal Women

Article

Full-text available

May 2023

Background: Sex hormone (SH) imbalances have been linked to a higher risk of heart failure in both sexes. However, mechanisms that underlie this relationship remain unclear. We examined the association of baseline SH with interstitial and replacement myocardial fibrosis in the MESA (Multi-Ethnic Study of Atherosclerosis) using cardiac magnetic resonance (CMR) T1 mapping and late gadolinium enhancement (LGE). Objectives: The purpose of this study was to assess the link between baseline sex hormone levels and myocardial fibrosis in the MESA cohort using CMR. Methods: A total of 2,324 participants (men and postmenopausal women [PMW]) were included in the MESA with SH measured at baseline and had underwent CMR 10 years later. All analyses were stratified by sex and age. Regression models were constructed to assess the associations of baseline SH with extracellular volume (ECV)% and native T1 time and with LGE. Higher native T1 time and ECV% are interpreted as evidence of increasing interstitial myocardial fibrosis (IMF). Given the limited number of myocardial scars present in PMW, analysis of LGE was limited to men. Results: Among older men (age ≥65 years), a 1-SD increment higher free testosterone was significantly associated with 2.45% lower ECV% and 21.5% lower native T1 time, while a 1-SD increment higher bioavailable testosterone was associated with 12.5% lower native T1 time. A 1-SD increment greater sex hormone-binding globulin level was associated with 1% higher ECV%. Among PMW of 55 to 64 years, a 1-SD increment higher total testosterone was associated with 9.5% lower native T1 time. Higher levels of estradiol in older men were independently associated with higher odds of having a myocardial scar (OR: 4.10; 95% CI: 1.35-12.40; P = 0.01). Conclusions: Among older men, SH imbalances at initial evaluation were independently associated with CMR defined IMF and replacement fibrosis, respectively; while increasing total testosterone in middle-aged PMW was associated with lesser marker of IMF. (JACC Adv 2023;2:100320) Published by Elsevier on behalf of the American College of Cardiology Foundation.

Higher testosterone and testosterone/estradiol ratio in men are associated with better epigenetic estimators of mortality risk

Preprint

Full-text available

Feb 2023

Introduction: Sex hormones are hypothesized to drive sex-specific health disparities. Here, we study the association between sex steroid hormones and DNA methylation-based (DNAm) biomarkers of age and mortality risk including Pheno Age Acceleration (AA), Grim AA, and DNAm-based estimators of Plasminogen Activator Inhibitor 1 (PAI1), and leptin concentrations. Methods: We pooled data from three population-based cohorts, the Framingham Heart Study Offspring Cohort (FHS), the Baltimore Longitudinal Study of Aging (BLSA), and the InCHIANTI Study, including 1,062 postmenopausal women without hormone therapy and 1,612 men of European descent. Sex hormone concentrations were standardized with mean 0 and standard deviation of 1, for each study and sex separately. Sex-stratified analyses using a linear mixed regression were performed, with a Benjamini-Hochberg (BH) adjustment for multiple testing. Sensitivity analysis was performed excluding the previously used training-set for the development of Pheno and Grim age. Results: Sex Hormone Binding Globulin (SHBG) is associated with a decrease in DNAm PAI1 among men (per 1 standard deviation (SD): -478 pg/mL; 95%CI: -614 to -343; P:1e-11; BH-P: 1e-10), and women (-434 pg/mL; 95%CI: -589 to -279; P:1e-7; BH-P:2e-6). The testosterone/estradiol (TE) ratio was associated with a decrease in Pheno AA (-0.41 years; 95%CI: -0.70 to -0.12; P:0.01; BH-P: 0.04), and DNAm PAI1 (-351 pg/mL; 95%CI: -486 to -217; P:4e-7; BH-P:3e-6) among men. In men, 1 SD increase in total testosterone was associated with a decrease in DNAm PAI1 (-481 pg/mL; 95%CI: -613 to -349; P:2e-12; BH-P:6e-11). Conclusion: SHBG was associated with lower DNAm PAI1 among men and women. Higher testosterone and testosterone/estradiol ratio were associated with lower DNAm PAI and a younger epigenetic age in men. A decrease in DNAm PAI1 is associated with lower mortality and morbidity risk indicating a potential protective effect of testosterone on lifespan and conceivably cardiovascular health via DNAm PAI1.

Association of sex steroid hormones and new bone formation rate after iliac onlay grafting: a prospective clinical pilot study

Article

Full-text available

Nov 2022

Purpose The present prospective study evaluates the association between new bone formation rate in the iliac onlay graft and sex steroid hormone serum levels. Methods A total of 15 partially or completely edentulous postmenopausal females and 9 males with less than 5 mm height of the remaining alveolar bone underwent iliac onlay grafting followed by dental implant placement using a two-stage approach. Sex hormone binding globulin and 17β-estradiol serum levels were investigated by electrochemiluminescence immunoassay, while total testosterone level was analyzed using radioimmunoassay. At the time of implant placement, 12 weeks after grafting, bone biopsies were obtained and analyzed histomorphometrically. Statistical analysis was performed using linear mixed models. Results Grafting procedure was successfully performed in all patients. The mean new bone formation rate was 32.5% (116 samples). In men the mean new bone formation rate (38.1%) was significantly higher ( p < 0.01) than in women (27.6%). Independent of gender 17β-estradiol and testosterone were positively associated to overall new bone formation rate, albeit a significant influence was only seen for 17β-estradiol in men ( p = 0.020). Sex hormone binding globulin had no influence on new bone formation rate ( p = 0.897). There was no significant association between new bone formation rate and age ( p = 0.353) or new bone formation rate and body mass index ( p = 0.248). Conclusion Positive association of 17ß-estradiol as well as testosterone with new bone formation rate after iliac onlay grafting indicates a role of sex steroid hormones in alveolar bone regeneration, although the observed influence was only significant for 17ß-estradiol in men. Graphical Abstract

Reference Intervals for Free Testosterone in Adult Men Measured Using a Standardized Equilibrium Dialysis Procedure

Article

Oct 2022

Background Free testosterone (FT) determination may be helpful in evaluating men suspected of testosterone deficiency especially in conditions with altered binding‐protein concentrations. However, methods for measuring FT by equilibrium dialysis and reference intervals vary among laboratories. Objective To determine reference intervals for FT in healthy, nonobese men by age groups as well as in healthy young men, 19–39 years, using a standardized equilibrium dialysis procedure Methods We measured FT in 145 healthy, nonobese men, 19 years or older, using a standardized equilibrium dialysis method performed for 16‐h at 37°C using undiluted serum and dialysis buffer that mimicked the ionic composition of human plasma. FT in dialysate was measured using a CDC‐certified liquid chromatography tandem mass spectrometry assay. Results In healthy nonobese men, the 2.5th, 10th, 50th, 90th, and 97.5th percentile values for FT were 66, 91, 141, 240, and 309 pg/ml, respectively; corresponding values for men, 19–39 years, were 120, 128, 190, 274, and 368 pg/ml, respectively. FT levels by age groups exhibit the expected age‐related decline. FT levels were negatively associated with body mass index, age, and sex hormone‐binding globulin (SHBG) levels. Percent FT was lower in middle‐aged and older men than young men adjusting for SHBG level. Discussion Further studies are needed to determine how these reference intervals apply to the diagnosis of androgen deficiency in clinical populations and in men of different races and ethnicities in different geographic regions. Conclusion Reference intervals for free FT levels (normative range 66–309 pg/ml [229–1072 pmol/L] in all men and 120–368 pg/ml [415–1274 pmol/L] in men, 19–39 years), measured using a standardized equilibrium dialysis method in healthy nonobese men, provide a rational basis for categorizing FT levels. These intervals require further validation in other populations, in relation to outcomes, and in randomized trials.

Impact of Vitamin C and Hydroxyurea on the Reproductive System Health in Male Rats

Article

Full-text available

Oct 2024

Ebtesam Abdulhadi

Hydroxyurea (HU) is a medication used to treat various diseases and is also being studied for its effects on spermatogenesis. Vitamin C (VC), an antioxidant, has been shown to protect sperm cells from oxidative stress, potentially improving fertility and sperm quality. In a study involving twenty-four adult male albino rats divided into four groups, Group 1 served as the control, Group 2 received 5 mg of vitamin C, Group 3 received 100 mg of hydroxyurea per body weight, and Group 4 received a combination of vitamin C and hydroxyurea to assess essential functions of the reproductive system, including hormone levels, antioxidant markers, oxidative stress indicators, histopathology, and identification of DNA damage. The study found that hydroxyurea significantly reduced testicular weight, SOD, CAT, and GSH while increasing FSH and MDA levels and causing abnormalities in sperm morphology. Hydroxyurea also caused apparent alterations in the histological structure of the testes and comet parameters. Rats treated with vitamin C showed a significant increase in absolute and relative epididymis weight compared to the control group. Moreover, vitamin C intervention reversed the adverse effects observed in rats fed hydroxyurea, indicating that low doses of vitamin C can protect against testicular damage.

Association of endogenous sex hormone levels with tooth loss due to periodontitis in men and post-menopausal women: The multi-ethnic study of atherosclerosis

Article

Jun 2024
J PERIODONTAL RES

Aim To investigate the association between endogenous sex hormone levels and history of tooth loss related to periodontitis in healthy middle‐aged to older men and post‐menopausal women. Methods This cross‐sectional study included 5649 participants aged 45–84 (mean age, 63 ± 10 years) from the Multi‐Ethnic Study of Atherosclerosis cohort who had sex hormone levels measured and answered a questionnaire regarding perceived periodontal status at exam 1. Multivariable logistic regression was used to examine the association of sex hormones (exposure) with history of tooth loss (outcome), stratified by sex. Results Among post‐menopausal women, higher free testosterone (per 1SD) was associated with a greater prevalence of tooth loss [OR 1.49 (95% CI, 1.08–2.05)], whereas higher sex hormone binding globulin (SHBG) was associated with a lower prevalence of tooth loss [OR 0.74 (0.58–0.94)], after adjustment for cardiometabolic risk factors and reproductive factors. In men, higher free testosterone and lower SHBG were associated with a lower prevalent probability of tooth loss in unadjusted analysis, but these associations lost significance after covariate adjustment. Conclusion A higher androgenic sex hormone profile in post‐menopausal women (i.e., increased free testosterone, lower SHBG) was associated with an increased prevalence of tooth loss, after adjusting cardiometabolic risk factors. No such association was found in men. These findings suggest that sex hormones may influence or serve as a marker for periodontal health.

Genetic correlations of alcohol consumption and alcohol use disorder with sex hormone levels in females and males

Preprint

Full-text available

Feb 2024

Background Alcohol consumption behaviors and alcohol use disorder risk and presentation differ by sex, and these complex traits are associated with blood concentrations of the steroid sex hormones, testosterone and estradiol, and their regulatory binding proteins, sex hormone binding globulin (SHBG) and albumin. Genetic variation is associated with alcohol consumption and alcohol use disorder, as well as levels of steroid sex hormones and their binding proteins. Methods To assess the contribution of genetic factors to previously described phenotypic associations between alcohol-use traits and sex-hormone levels, we estimated genetic correlations (rg) using summary statistics from prior published, large sample size genome-wide association studies (GWAS) of alcohol consumption, alcohol dependence, testosterone, estradiol, SHBG, and albumin. Results For alcohol consumption, we observed positive genetic correlation (i.e. genetic effects in the same direction) with total testosterone in males (rg = 0.084, p = 0.007) and trends toward positive genetic correlation with bioavailable testosterone (rg = 0.060, p = 0.084) and SHBG in males (rg = 0.056, p = 0.086) and with albumin in a sex-combined cohort (rg = 0.082, p = 0.015); however in females, we observed positive genetic correlation with SHBG (rg = 0.089, p = 0.004) and a trend toward negative genetic correlation (i.e. genetic effects in opposite directions) with bioavailable testosterone (rg = -0.064, p = 0.032). For alcohol dependence, we observed a trend toward negative genetic correlation with total testosterone in females (rg = -0.106, p = 0.024) and positive genetic correlation with BMI-adjusted SHBG in males (rg = 0.119, p = 0.017). Several of these genetic correlations differed between females and males and were not in the same direction as the corresponding phenotypic associations. Conclusions Findings suggest that shared genetic effects may contribute to positive associations of alcohol consumption with albumin in both sexes, as well as positive associations between alcohol consumption and bioavailable testosterone and between alcohol dependence and SHBG in males. However, relative contributions of heritable and environmental factors to associations between alcohol-use traits and sex-hormone levels may differ by sex, with genetic factors contributing more in males and environmental factors contributing more in females.

Psychoneuroendocrine profiles of unmedicated men with major depressive disorder and associations to treatment effects and sexual side-effects

Article

Full-text available

Feb 2024

Sex-steroid hormones and risk of postmenopausal estrogen receptor-positive breast cancer: a case–cohort analysis

Article

Full-text available

Feb 2024
CANCER CAUSE CONTROL

Purpose Sex-steroid hormones are associated with postmenopausal breast cancer but potential confounding from other biological pathways is rarely considered. We estimated risk ratios for sex-steroid hormone biomarkers in relation to postmenopausal estrogen receptor (ER)-positive breast cancer, while accounting for biomarkers from insulin/insulin-like growth factor-signaling and inflammatory pathways. Methods This analysis included 1208 women from a case–cohort study of postmenopausal breast cancer within the Melbourne Collaborative Cohort Study. Weighted Poisson regression with a robust variance estimator was used to estimate risk ratios (RRs) and 95% confidence intervals (CIs) of postmenopausal ER-positive breast cancer, per doubling plasma concentration of progesterone, estrogens, androgens, and sex-hormone binding globulin (SHBG). Analyses included sociodemographic and lifestyle confounders, and other biomarkers identified as potential confounders. Results Increased risks of postmenopausal ER-positive breast cancer were observed per doubling plasma concentration of progesterone (RR: 1.22, 95% CI 1.03 to 1.44), androstenedione (RR 1.20, 95% CI 0.99 to 1.45), dehydroepiandrosterone (RR: 1.15, 95% CI 1.00 to 1.34), total testosterone (RR: 1.11, 95% CI 0.96 to 1.29), free testosterone (RR: 1.12, 95% CI 0.98 to 1.28), estrone (RR 1.21, 95% CI 0.99 to 1.48), total estradiol (RR 1.19, 95% CI 1.02 to 1.39) and free estradiol (RR 1.22, 95% CI 1.05 to 1.41). A possible decreased risk was observed for SHBG (RR 0.83, 95% CI 0.66 to 1.05). Conclusion Progesterone, estrogens and androgens likely increase postmenopausal ER-positive breast cancer risk, whereas SHBG may decrease risk. These findings strengthen the causal evidence surrounding the sex-hormone-driven nature of postmenopausal breast cancer.

The Assessment of Liver Function Test and Fertility Hormones in Saudi Athletes Using Anabolic Androgenic Steroids

Article

Full-text available

Jan 2024

Background A growing number of athletes are using synthetic anabolic–androgenic steroids (AAS), comprised of testosterone and other derivatives, to enhance athletic performance and muscle mass. Over the years, numerous reports elucidated the side effects of the illegal use of AAS, such as infertility, and liver disorders. The effect of AAS on the hepatic and reproductive systems in Saudi athletes has not yet been studied. Therefore, this study examined the liver function and sex hormone parameters of AAS users as compared to non-users. Methods Fasting blood samples were collected from 16 male Saudi athletes, 10 AAS-users (cases) and 6 non-users (controls) to measure liver function tests (ALT, AST, GGT, ALP, total protein, albumin, direct and total bilirubin) and muscle enzymes (CK, LDH), Fertility hormones (LH, FSH, total testosterone, estradiol, and prolactin) were included also. Furthermore, a self-reported questionnaire was obtained to identify the type of AAS used, the dosage, and the length of the course before sample collection. Results The results show a statistically significant increase in ALT (P < 0.001), AST (P < 0.001), CK (P < 0.05), and a significant decrease (P < 0.05) in albumin (P < 0.001) and total bilirubin levels (P < 0.01) in AAS-users. Total testosterone increased significantly among AAS (P < 0.05), along with a significant decrease in LH (P < 0.01), and FSH (P < 0.001) levels, while serum prolactin and estradiol levels were significantly increased (P < 0.05). Conclusion AAS can enhance physical performance and appearance, its potential adverse effects on the hepatic and reproductive systems necessitate careful consideration. Our research demonstrates an increase in the liver-specific enzyme ALT in AAS users relative to non-users and the possibility that short-term AAS usage increases the risk of liver injury.

DHA (omega-3 fatty acid) and estradiol: key roles in regional cerebral glucose uptake

Article

Full-text available

Nov 2023

Neurons have a high energy need, requiring a continuous supply of glucose from the blood. Tight regulation of glucose metabolism in response to stimuli is essential for brain physiology. Glucose metabolism and cerebral blood flow are closely coordinated during neuronal activity to maintain proper brain function. Glucose uptake across the blood-brain barrier is facilitated by a carrier protein: the GLUT-1 transporter. The first way the body meets urgent demand for glucose is to increase the blood flow through vasodilatory responses generated by nitric oxide. If that is insufficient, the second way is to increase the density of GLUT-1 through the translocation of this transporter from intracellular stores. The third pathway is to increase GLUT-1 synthesis by stimulating SLC2A1 (GLUT-1 gene) transcription. A tandem of two key molecules, free estradiol and DHA, is involved in this critical regulation. Their relationship is synergistic and reciprocal: free estradiol with genomic and non-genomic actions via ERα, and DHA via the PPARα-RXRα and PPARɣ-RXRα heterodimers. We highlight several original mechanisms linking two main principles (neuronal stimulation and brain energy metabolism) with the fundamental roles played by DHA and free estradiol. In particular, it has been shown that from a certain level of chronic DHA deficiency, a permanent imbalance sets in with disturbances in glucose intake and brain metabolism. This DHA deficiency is an aggravating factor in some neuropathologies.

Sex-steroid hormones and risk of postmenopausal estrogen receptor-positive breast cancer: a case-cohort analysis

Preprint

Full-text available

Oct 2023

Purpose Sex-steroid hormones are associated with postmenopausal breast cancer but potential confounding from other biological pathways is rarely considered. We estimated risk ratios for sex-steroid hormone biomarkers in relation to postmenopausal estrogen receptor (ER)-positive breast cancer, while accounting for biomarkers from insulin/insulin-like growth factor-signaling and inflammatory pathways. Methods This analysis included 1,208 women from a case-cohort study of postmenopausal breast cancer within the Melbourne Collaborative Cohort Study. Weighted Poisson regression with a robust variance estimator was used to estimate risk ratios (RRs) and 95% confidence intervals (CIs) of postmenopausal ER-positive breast cancer, per doubling plasma concentration of progesterone, estrogens, androgens, and sex hormone binding globulin (SHBG). Analyses included sociodemographic and lifestyle confounders, and other biomarkers identified as potential confounders. Results Increased risks of postmenopausal ER-positive breast cancer were observed per doubling plasma concentration of progesterone (RR: 1.22, 95% CI: 1.03 to 1.44), androstenedione (RR: 1.20, 95% CI: 0.99 to 1.45), dehydroepiandrosterone (RR: 1.15, 95% CI: 1.00 to 1.34), total testosterone (RR: 1.11, 95% CI: 0.96 to 1.29), free testosterone (RR: 1.12, 95% CI: 0.98 to 1.28), estrone (RR: 1.21, 95% CI: 0.99 to 1.48), total estradiol (RR: 1.19, 95% CI: 1.02 to 1.39) and free estradiol (RR: 1.22, 95% CI: 1.05 to 1.41). A possible decreased risk was observed for SHBG (RR: 0.83, 95% CI: 0.66 to 1.05). Conclusion Progesterone, estrogens and androgens likely increase postmenopausal ER-positive breast cancer risk, whereas SHBG may decrease risk. These findings strengthen the causal evidence surrounding the sex hormone-driven nature of postmenopausal breast cancer.

Sex Hormones, the Stool Microbiome, and Subclinical Atherosclerosis in Women With and Without HIV

Article

Aug 2023

Background The cardio-protective roles of endogenous estrogens may be particularly important in women with HIV, who have reduced estrogen exposure and elevated cardiovascular disease risk. The gut microbiome metabolically interacts with sex hormones, but little is known regarding how such interplay may impact cardiovascular risk. Methods Among 197 post-menopausal women in the Women’s Interagency HIV Study, we measured 15 sex hormones in serum and assessed the gut microbiome in stool. B-mode ultrasound was used to determine presence of carotid artery plaque in a subset (n = 134). We examined associations of (1) sex hormones and stool microbiome, (2) sex hormones and plaque, and (3) sex hormone-related stool microbiota and plaque, adjusting for potential confounders. Results Participant median age was 58 years and the majority were living with HIV (81%). Sex hormones (estrogens, androgens, and adrenal precursors) were associated with stool microbiome diversity and specific species, similarly in women with and without HIV. For example, estrogens were associated with higher diversity, higher abundance of species from Alistipes, Collinsella, Erysipelotrichia, and Clostridia, and higher abundance of microbial β-glucuronidase and aryl-sulfatase orthologs, which are involved in hormone metabolism. Several hormones were associated with lower odds of carotid artery plaque, including dihydrotestosterone, 3α-diol-17G, estradiol, and estrone. Exploratory mediation analysis suggested that estrone-related species, particularly from Collinsella, may mediate the protective association of estrone with plaque. Conclusion Serum sex hormones are significant predictors of stool microbiome diversity and composition, likely due in part to metabolic interactions. The gut microbiome may play a role in estrogen-related cardiovascular protection.

Alcohol intake and endogenous sex hormones in women: meta-analysis of cohort studies and Mendelian randomization

Preprint

Full-text available

Aug 2023

Background The mechanisms underlying alcohol-induced breast carcinogenesis are not fully understood but may involve hormonal changes. Methods We investigated cross-sectional associations between self-reported alcohol intake and serum or plasma concentrations of oestradiol, oestrone, progesterone (in pre-menopausal women only), testosterone, androstenedione, DHEAS (dehydroepiandrosterone sulphate) and SHBG (sex hormone binding globulin) in 45 431 pre-menopausal and 173 476 post-menopausal women. We performed multivariable linear regression separately for UK Biobank, EPIC (European Prospective Investigation into Cancer and Nutrition) and EHBCCG (Endogenous Hormones and Breast Cancer Collaborative Group), and meta-analysed the results. For testosterone and SHBG, we also conducted two-sample Mendelian Randomization (MR) and colocalisation using the ADH1B (Alcohol Dehydrogenase 1B) variant (rs1229984). Results Alcohol intake was positively, though weakly, associated with all hormones (except progesterone in pre-menopausal women), with increments in concentrations per 10 g/day increment in alcohol intake ranging from 1.7% for luteal oestradiol to 6.6% for post-menopausal DHEAS. There was an inverse association of alcohol with SHBG in post-menopausal women but a small positive association in pre-menopausal women. MR identified positive associations of alcohol intake with total testosterone (difference per 10 g/day increment: 4.1%; 95% CI: 0.6%, 7.6%) and free testosterone (7.8%; 4.1%, 11.5%), and an inverse association with SHBG (-8.1%; -11.3%, -4.9%). Colocalisation suggested a shared causal locus at ADH1B between alcohol intake and higher free testosterone and lower SHBG (PP4: 0.81 and 0.97 respectively). Conclusions Alcohol intake was associated with small increases in sex hormone concentrations, including bioavailable fractions, which may contribute to its effect on breast cancer risk.

Development and validation of a blood biomarker score for predicting mortality risk in the general population

Article

Full-text available

Jul 2023
J TRANSL MED

Background Blood biomarkers for multiple pathways, such as inflammatory response, lipid metabolism, and hormonal regulation, have been suggested to influence the risk of mortality. However, few studies have systematically evaluated the combined predictive ability of blood biomarkers for mortality risk. Methods We included 267,239 participants from the UK Biobank who had measurements of 28 blood biomarkers and were free of cardiovascular disease (CVD) and cancer at baseline (2006–2010). We developed sex-specific blood biomarker scores for predicting all-cause mortality risk in a training set of 247,503 participants from England and Wales, and validated the results in 19,736 participants from Scotland. Cox and LASSO regression analyses were performed to identify independent predictors for men and women separately. Discrimination and calibration were evaluated by C-index and calibration plots, respectively. We also assessed mediating effects of the biomarkers on the association between traditional risk factors (current smoking, obesity, physical inactivity, hypertension, diabetes) and mortality. Results A total of 13 independent predictive biomarkers for men and 17 for women were identified and included in the score development. Compared to the lowest tertile of the score, the highest tertile showed a hazard ratio of 5.36 (95% confidence interval [CI] 5.04–5.71) in men and 4.23 (95% CI 3.87–4.62) in women for all-cause mortality. In the validation set, the score yielded a C-index of 0.73 (95% CI 0.72–0.75) in men and 0.70 (95% CI 0.68–0.73) in women for all-cause mortality; it was also predictive of CVD (C-index of 0.76 in men and 0.79 in women) and cancer (C-index of 0.70 in men and 0.67 in women) mortality. Moreover, the association between traditional risk factors and all-cause mortality was largely mediated by cystatin C, C-reactive protein, 25-hydroxyvitamin D, and hemoglobin A1c. Conclusions We established sex-specific blood biomarker scores for predicting all-cause and cause-specific mortality in the general population, which hold the potential to identify high-risk individuals and improve targeted prevention of premature death.

Serum DHEA and Testosterone Levels Associate Inversely With Coronary Artery Calcification in Elderly Men

Article

Full-text available

Jun 2023
J CLIN ENDOCR METAB

Context: Epidemiological as well as preclinical data support cardiovascular, mainly protective, effects of sex steroids in men, but the mechanisms underlying the cardiovascular actions of sex steroids are poorly understood. Vascular calcification parallels the development of atherosclerosis, but is increasingly recognized as a diversified, highly regulated process, which itself may have pathophysiological importance for clinical cardiovascular events. Objective: To investigate the association between serum sex steroids and coronary artery calcification (CAC) in elderly men. Design, setting and participants: We used gas chromatography-tandem mass spectrometry to analyze a comprehensive sex steroid profile, including levels of dehydroepiandrosterone (DHEA), androstenedione, estrone, testosterone, estradiol and dihydrotestosterone, in men from the population-based AGES-Reykjavik study (n=1287, mean 76 years). Further, sex hormone-binding globulin (SHBG) was assayed and bioavailable hormone levels calculated. CAC score was determined by computed tomography. Main outcome measures: Cross-sectional associations between dehydroepiandrosterone, androstenedione, estrone, testosterone, dihydrotestosterone, and estradiol and quintiles of CAC. Results: Serum levels of DHEA, androstenedione, testosterone, dihydrotestosterone and bioavailable testosterone showed significant inverse associations with CAC, while estrone, estradiol, bioavailable estradiol and SHBG did not. DHEA, testosterone and bioavailable testosterone remained associated with CAC after adjustment for traditional cardiovascular risk factors. In addition, our results support partially independent associations between adrenal-derived DHEA and testes-derived testosterone and CAC. Conclusions: Serum levels of DHEA and testosterone are inversely associated with CAC in elderly men, partially independently from each other. These results raise the question whether androgens from both the adrenals and the testes may contribute to male cardiovascular health.

Can maternal postpartum testosterone and estradiol retrospectively predict the offspring's sex at birth? A cross-sectional study in Ghana

Article

Full-text available

Jun 2023

The selection of X-or Y-bearing spermatozoa during fertilization may depend on maternal circulating sex hormones. The zona pellucida of the developing oocyte is adapted to be selective for the Y-bearing spermatozoa when maternal circulating androgens are relatively high. This study sought to determine whether maternal postpartum testosterone and estradiol can retrospectively predict the offspring sex at birth. The study was cross-sectional from December 2020 to April 2021 at the Reproductive and Child Health unit in Tamale. The participants were part of a previous study and comprised 178 mother-offspring dyads (mother-daughter = 90, mother-son = 88). The mothers were between the ages of 18 and 35 years and had a median (interquartile range-IQR) postpartum interval of 111 (60-187) days. A single venous blood sample was drawn from the mothers between 8.00 am and 12.00 pm local time on each day to reduce diurnal variation. Postpartum serum estradiol, testosterone, and sex hormone-binding globulin were assayed using the ELISA technique. The serum total testosterone and the testosterone-to-estradiol ratio (TT: E 2) were higher in mothers with sons while estradiol was higher in mothers with daughters (p < 0.050). The total testosterone and TT: E 2 did not markedly differ by their area under the curve (AUC: 0.91 and 0.99, respectively) but both were higher than the AUC of estradiol (0.72). The Sensitivity was 97.7%, 97.7%, and 94.5% and specificity, 88.9%, 40.0%, and 95.5% at cutoff points of >1.659 nmol/L, ≤141.862 pmol/L, and > 31.5, respectively for total testosterone, estradiol, and TT: E 2. The maternal testosterone-to-estradiol ratio may be more predictive of offspring sex at birth than either testosterone or estradiol alone. K E Y W O R D S estradiol, Ghana, maternal hormones, sex at birth, testosterone

Endogenous Sex Steroid Hormones and Risk of Liver Cancer among U.S. Men: Results from the Liver Cancer Pooling Project

Article

Full-text available

Mar 2023

Background & aims: Incidence rates of liver cancer in most populations are two to three times higher among men than women. The higher rates among men have led to the suggestion that androgens are related to increased risk whereas oestrogens are related to decreased risk. This hypothesis was investigated in the present study via a nested case-control analysis of pre-diagnostic sex steroid hormone levels among men in five US cohorts. Methods: Concentrations of sex steroid hormones and sex hormone-binding globulin were quantitated using gas chromatography-mass spectrometry and a competitive electrochemiluminescence immunoassay, respectively. Multivariable conditional logistic regression was used to calculate odds ratios (ORs) and 95% CIs for associations between hormones and liver cancer among 275 men who subsequently developed liver cancer and 768 comparison men. Results: Higher concentrations of total testosterone (OR per one-unit increase in log2 = 1.77, 95% CI = 1.38-2.29), dihydrotestosterone (OR = 1.76, 95% CI = 1.21-2.57), oestrone (OR = 1.74, 95% CI = 1.08-2.79), total oestradiol (OR = 1.58, 95% CI=1.22-20.05), and sex hormone-binding globulin (OR = 1.63, 95% CI = 1.27-2.11) were associated with increased risk. Higher concentrations of dehydroepiandrosterone (DHEA), however, were associated with a 53% decreased risk (OR = 0.47, 95% CI = 0.33-0.68). Conclusions: Higher concentrations of both androgens (testosterone, dihydrotestosterone) and their aromatised oestrogenic metabolites (oestrone, oestradiol) were observed among men who subsequently developed liver cancer compared with men who did not. As DHEA is an adrenal precursor of both androgens and oestrogens, these results may suggest that a lower capacity to convert DHEA to androgens, and their subsequent conversion to oestrogens, confers a lower risk of liver cancer, whereas a greater capacity to convert DHEA confers a greater risk. Impact and implications: This study does not fully support the current hormone hypothesis as both androgen and oestrogen levels were associated with increased risk of liver cancer among men. The study also found that higher DHEA levels were associated with lower risk, thus suggesting the hypothesis that greater capacity to convert DHEA could be associated with increased liver cancer risk among men.

Sex differences in the associations of body size and body shape with platelets in the UK Biobank cohort

Article

Full-text available

Feb 2023

Highlights We examined a large middle-aged population-based cohort, excluding participants with prevalent cancer, endocrine and metabolic conditions, and severe illnesses. Body mass index (BMI) was associated positively with platelet count in women (strongest in pre-menopausal women) and inversely in men (strongest in older men), but inversely with platelet size in pre-menopausal women and positively in post-menopausal women and men. Alcohol consumption and smoking shifted the association of BMI with platelet count towards the null for women and towards a stronger inverse association for men, but did not affect the associations with waist or hip size. Waist size was associated positively with platelet count in women and men, with only a weak inverse association for hip size. Waist size was associated inversely and hip size positively with platelet size, mainly in women.

Association of total and free testosterone with cardiovascular disease in a nationally representative sample of white, black, and Mexican American men

Article

Full-text available

Dec 2022

Associations of total testosterone (T) and calculated free T with cardiovascular disease (CVD) remain poorly understood. Particularly how these associations vary according to race and ethnicity in a nationally representative sample of men. Data included 7058 men (≥20 years) from NHANES. CVD was defined as any reported diagnosis of heart failure (HF), coronary artery disease (CAD), myocardial infarction (MI), and stroke. Total T (ng/mL) was obtained among males who participated in the morning examination. Weighted multivariable-adjusted logistic regression models were conducted. We found associations of low T (OR = 1.57, 95% CI = 1.17–2.11), low calculated free T (OR = 1.53, 95% CI = 1.10–2.17), total T (Q1 vs Q5), and calculated free T (Q1 vs Q5) with CVD after adjusting for estradiol and SHBG. In disease specific analysis, low T increased prevalence of MI (OR = 1.72, 95% CI = 1.08–2.75) and HF (OR = 1.74, 95% CI = 1.08–2.82), but a continuous increment of total T reduced the prevalence of CAD. Similar inverse associations were identified among White and Mexican Americans, but not Blacks (OR = 0.93, 95% CI = 0.49–1.76). Low levels of T and calculated free T were associated with an increased prevalence of overall CVD and among White and Mexican Americans. Associations remained in the same direction with specific CVD outcomes in the overall population.

Article

Nov 2022

Sleep disruption and circadian disruption have been proposed to be risk factors of breast cancer. The present study examined the associations of sleep-related factors, referring to night shift work, sleep habits, and sleep disturbances, with the plasma levels of sex hormones in premenopausal Japanese women. Study participants were 432 women who had regular menstrual cycles less than 40 days long. Information on their history of night shift work and sleep disturbances was obtained using a self-administered questionnaire. Information on their sleep habits, such as usual wake-up times, bedtimes, and ambient light level while sleeping, was obtained in an interview. The participants’ height and weight were measured. Plasma concentrations of estradiol, testosterone, dehydroepiandrosterone sulfate, sex hormone-binding globulin (SHBG), FSH, and LH were also measured. After controlling for the phase of the menstrual cycle and other covariates, more years of night shift work ≥ once a week during the past 10 years was significantly associated with a lower SHBG and a higher free estradiol level. Shorter sleep duration was significantly associated with the higher total, bioavailable, and free testosterone levels. Sleep disturbance by awaking after sleep onset was significantly associated with a high free estradiol level. The data suggest that long-term night shift work, short sleep duration, and arousal during sleep are associated with higher estradiol or testosterone levels in premenopausal women.

Diagnosis of hypogonadism in ageing men

Article

Full-text available

Nov 2022
REV ENDOCR METAB DIS

Jean-Marc Kaufman

To make the diagnosis of hypogonadism in an ageing man, in absence of rare organic cause often referred to as functional or late onset hypogonadism (LOH), he should present with a clinical syndrome suggestive of androgen deficiency and have consistently low serum testosterone (T) levels. This does not differ from the diagnosis of any other form of hypogonadism. Particular to LOH diagnostic are uncertainties surrounding this entity: signs and symptoms of androgen deficiency (including sexual symptoms) are nonspecific in older men; clinical significance of only moderately low T levels is uncertain; comorbidity plays a substantial role with potential for reversibility; the place of T therapy in these men is debatable. This context demands for a pragmatic, but appropriately conservative approach to diagnosis. Evaluation should be stepwise with clinical evaluation, if suggestive for androgen deficiency, followed by measurement of a fasting morning serum T, if unequivocally low to be confirmed in a separate morning sample by a second low T or, if initial T borderline low or in presence of factors known to affect SHBG, by a low calculated free T level. All other (free) T results make hypogonadism an unlikely cause of the patient’s symptoms. In the absence of consensus cut-off levels for total and free T in the published clinical guidelines for diagnosis of hypogonadism, it seems appropriate in the context of LOH to use stringent criteria indicating a convincingly low serum T. The approach to the diagnosis of LOH is not fundamentally different from that of other forms of hypogonadism but should put extra weight on prioritizing the shunning of overdiagnosis above the risk of underdiagnosis.

Role of sex hormone-binding globulin in the free hormone hypothesis and the relevance of free testosterone in androgen physiology

Article

Full-text available

Oct 2022
CELL MOL LIFE SCI

According to the free hormone hypothesis, biological activity of a certain hormone is best reflected by free rather than total hormone concentrations. A crucial element in this theory is the presence of binding proteins, which function as gatekeepers for steroid action. For testosterone, tissue exposure is governed by a delicate equilibrium between free and total testosterone which is determined through interaction with the binding proteins sex hormone-binding globulin and albumin. Ageing, genetics and various pathological conditions influence this equilibrium, hereby possibly modulating hormonal exposure to the target tissues. Despite ongoing controversy on the subject, strong evidence from recent in vitro, in vivo and human experiments emphasizes the relevance of free testosterone. Currently, however, clinical possibilities for free hormone diagnostics are limited. Direct immunoassays are inaccurate, while gold standard liquid chromatography with tandem mass spectrometry (LC–MS/MS) coupled equilibrium dialysis is not available for clinical routine. Calculation models for free testosterone, despite intrinsic limitations, provide a suitable alternative, of which the Vermeulen calculator is currently the preferred method. Calculated free testosterone is indeed associated with bone health, frailty and other clinical endpoints. Moreover, the added value of free testosterone in the clinical diagnosis of male hypogonadism is clearly evident. In suspected hypogonadal men in whom borderline low total testosterone and/or altered sex hormone-binding globulin levels are detected, the determination of free testosterone avoids under- and overdiagnosis, facilitating adequate prescription of hormonal replacement therapy. As such, free testosterone should be integrated as a standard biochemical parameter, on top of total testosterone, in the diagnostic workflow of male hypogonadism.

Endogenous Levels of Circulating Androgens Are Not Associated with Risk of Microscopic Colitis

Article

Full-text available

Aug 2022
DIGEST DIS SCI

Background Microscopic colitis is a chronic inflammatory disease that most commonly affects post-menopausal women. Exogenous hormone use has recently been linked with increased risk of microscopic colitis. Yet, it is unclear whether levels of endogenous sex hormones are also associated with risk of microscopic colitis.AimTo evaluate the association between prediagnostic plasma androgens and subsequent risk of microscopic colitis.Methods We conducted a case–control study nested within prospective cohort studies of the Nurses' Health Study (NHS) and NHSII. Cases of microscopic colitis were each matched to two controls according to age, cohort, menopause status, fasting status, and season of plasma collection. Prediagnosis plasma levels of androgens including dehydroepiandrosterone sulfate, testosterone, and sex hormone-binding globulin were measured. We examined the association of each analyte with risk of microscopic colitis using conditional logistic regression models.ResultsOur study included 96 cases of microscopic colitis matched to 190 controls. Plasma levels of testosterone were not associated with risk of microscopic colitis (Ptrend = 0.70). Compared to participants in the lowest quartile of plasma testosterone levels, the aOR of microscopic colitis for women in the highest quartile was 0.88, 95% CI 0.45–1.71. Similarly, we did not observe an association between dehydroepiandrosterone sulfate and sex hormone–binding globulin and risk of microscopic colitis (all Ptrend > 0.52).Conclusion Among women, prediagnostic circulating levels of testosterone, dehydroepiandrosterone sulfate, and sex hormone–binding globulin are not associated with risk of microscopic colitis.

The relationship between 2D:4D ratio and postpartum adult female variables in a Ghanaian population

Article

Full-text available

Sep 2021
AM J HUM BIOL

Objectives: Postpartum hematological and anthropometric assessment is a requirement for optimal maternal and child health. The study aimed to determine the relationship between the 2D:4D ratio and postpartum hematological and anthropometric variables in adult females. Methods: The study was cross-sectional from December 2020 to April 2021 involving 272 postpartum adult females, aged between 18 and 36 years. The right (2D:4DR) and the left (2D:4DL) digit ratios were measured using computer-assisted analysis. Fasting venous samples were collected at a median (interquartile range) of 111 (44-210) days postpartum and analyzed for total testosterone (TT), estradiol, sex hormone-binding globulin, and complete blood count. Results: The mean ± standard deviation 2D:4DR and 2D:4DL were 0.94 ± 0.04 and 0.93 ± 0.04, respectively. As expected, the TT (r = À0.198, p = .015) and the free androgen index (FAI: r = À0.186, p = .019) were inversely correlated with the 2D:4DL while free testosterone (FT%: r = À0.157, p = .038) was inversely correlated with the 2D:4DR. The absolute basophile count (BASO: r = À0.124, p = .040) and the platelet-neutrophil ratio (PLR: r = À0.153, p = .016) were inversely correlated with the 2D:4DL and the 2D:4DR respectively. In addition, the mean cell volume was inversely correlated with the 2D:4DR (r = À0.139, p = .024) and the 2D:4DL (r = À0.122, p = .045). Moreover, the 2D:4DR was inversely correlated with height (r = À0.164, p = .007). Unexpectedly, the red blood cell count (RBC: r = 0.138, p = .025) was positively correlated with the 2D:4DR. Conclusion: There are significant relationships between the 2D:4D ratio and postpartum female variables. These findings are useful preliminary reference data for postpartum research and subsequent 2D:4D ratio studies.

Sociodemographic, lifestyle, and medical factors associated with calculated free testosterone concentrations in men: individual participant data meta-analyses

Article

Oct 2024
EUR J ENDOCRINOL

Objective Sociodemographic, lifestyle, and medical variables influence total testosterone (T) and sex hormone-binding globulin (SHBG) concentrations. The relationship between these factors and “free” T remains unclear. We examined 21 sociodemographic, lifestyle, and medical predictors influencing calculated free T (cFT) in community-dwelling men across ages. Design This is a cross-sectional analysis in 20 631 participants in the Androgens in Men Study. Methods Individual participant data (IPD) were provided by 9 cohorts. Total T was determined using mass spectrometry, SHBG using immunoassays, and cFT using the Vermeulen formula. Associations were analyzed using 2-stage random effects IPD meta-analyses. Results Cohort median ages ranged from 40 to 76 years and median cFT concentrations from 174.3 to 422.8 pmol/L. In men aged 17-99 years, there was a linear inverse association of cFT with age (−57.2 pmol/L [95% confidence interval, −69.4, −44.9] per 1 SD increase in age). Calculated free T increased with increasing baseline body mass index (BMI) among men with BMI < 23.6 kg/m2, but decreased among men with BMI > 23.6 kg/m2 (−24.7 pmol/L [−29.1, −20.3] per 1 SD increase in the 25.4-29.6 kg/m2 BMI range). Calculated free T was lower in younger men, who were married or in a de facto relationship (−18.4 pmol/L [−27.6, −9.3]) and in men who formerly smoked (−5.7 pmol/L [−8.9, −2.6]), were in poor general health (−14.0 pmol/L [−20.1, −7.8]), and had diabetes (−19.6 pmol/L [−23.0, −16.3]), cardiovascular disease (−5.8 pmol/L [−8.3, −3.2]), or cancer (−19.2 pmol/L [−24.4, −14.1]). Conclusions Calculated free T was most prominently associated with age and BMI. The linear, inverse association with age, nonlinear association with BMI, and presence of diabetes, cancer, and sociodemographic factors should be considered when interpreting cFT values.

Immunodetection of Poorly Soluble Substances: Limitations and Their Overcoming

Article

Oct 2024
CRIT REV ANAL CHEM

Immunoassays based on the specific antigen-antibody interactions are efficient tools to detect various compounds and estimate their content. Usually, these assays are implemented in water-saline media with composition close to physiological conditions. However, many substances are insoluble or cannot be molecularly dispersed in such media, which objectively creates problems when interacting in aquatic environments. Thus, obtaining immunoreactants and implementing immunoassays of these substances need special methodological solutions. Hydrophobicity of antigens as well as their limited ability to functionalization and conjugation are often overlooked when developing immunoassays for these compounds. The main key finding is the possibility to influence the behavior of hydrophobic compounds for immunoassays, which requires specific approaches summarized in the review. Using the examples of two groups of compounds-surfactants (alkyl- and bisphenols) and fullerenes, we systematized the existing knowledge and experience in the development of immunoassays. This review addresses the challenges of immunodetection of poorly soluble substances and proposes solutions such as the use of hydrotropes, other solubilization techniques, and alternative receptors (aptamers and molecularly imprinted polymers).

Prospective Analysis of Circulating Biomarkers and Ovarian Cancer Risk in the UK Biobank

Article

Jul 2024
CANCER EPIDEM BIOMAR

Background Risk factors have a limited ability to predict individuals at high risk of developing ovarian cancer among average-risk women, highlighting the need for discovery of novel biomarkers. In the UK Biobank, we investigated serum biomarkers commonly measured in clinical laboratory tests and ovarian cancer risk. Methods We conducted a prospective analysis of 20 serum biomarkers and ovarian cancer risk in 232,037 female UK Biobank participants (including 1,122 incident ovarian cancer cases diagnosed from 2006 to 2020). Multivariable adjusted Cox proportional hazards models were used to examine associations between biomarkers and ovarian cancer risk overall and by histotype. FDR was used to account for multiple testing. Results Overall, higher levels of insulin-like growth factor (IGF)-1 [RRquartile 4 vs. 1 = 0.73; 95% confidence interval (CI), 0.60–0.87; P-trend = 0.002/FDR = 0.04], HbA1c (RRquartile 4 vs. 1 = 0.74; 95% CI, 0.62–0.89; P-trend = 0.002/FDR = 0.04), and alanine aminotransferase (RRquartile 4 vs. 1 = 0.76; 95% CI, 0.63–0.91; P-trend = 0.002/FDR = 0.04) were significantly associated with lower ovarian cancer risk. When stratified by histotype, higher IGF1 levels were associated with lower risk of serous (RRquartile 4 vs. 1 = 0.73; 95% CI, 0.58–0.91; P-trend = 0.01/FDR = 0.20) and clear cell tumors (RRquartile 4 vs. 1 = 0.18; 95% CI, 0.07–0.49; P-trend = 0.001/FDR = 0.02), and higher HbA1c levels were associated with lower risk of serous tumors (RRquartile 4 vs. 1 = 0.73; 95% CI, 0.59–0.90; P-trend = 0.004/FDR = 0.08). Conclusions We observed that higher levels of circulating IGF1, HbA1c, and alanine aminotransferase were associated with lower ovarian cancer risk. Impact These results suggest metabolism of glucose/amino acid and insulin/IGF1 signaling pathway may be contributing to ovarian carcinogenesis. Further research is needed to replicate our findings and elucidate how systemic changes in metabolism impact ovarian carcinogenesis.

Levels of Sex Hormones and Abdominal Muscle Composition in Men from The Multi-Ethnic Study of Atherosclerosis

Article

Full-text available

Jul 2024

Information on the associations of testosterone levels with abdominal muscle volume and density in men is limited, while the role of estradiol and SHBG on these muscle characteristics are unclear. Therefore, this study aimed to investigate the association between fasting serum sex hormones and CT-derived abdominal muscle area and radiodensity in adult men. Conducted as a cross sectional observational study using data from the Multi-Ethnic Study of Atherosclerosis, our analyses focused on a community-based sample of 907 men aged 45–84 years, with 878 men having complete data. CT scans of the abdomen were interrogated for muscle characteristics, and multivariable linear regressions were used to test the associations. After adjustment for relevant factors, higher levels of both total testosterone and estradiol were associated with higher abdominal muscle area (1.74, 0.1–3.4, and 1.84, 0.4–3.3, respectively). In the final analyses, levels of total testosterone showed a positive association, while an inverse relationship was observed for SHBG with abdominal muscle radiodensity (0.3, 0.0–0.6, and − 0.33, − 0.6 to − 0.1, respectively). Our results indicate a complex association between sex hormones and abdominal muscle characteristics in men. Specifically, total testosterone and estradiol were associated with abdominal muscle area, while only total testosterone was associated with muscle radiodensity and SHBG was inversely associated with muscle radiodensity. Clinical Trial: NCT00005487

Menopause and Estrogen Associations With Gut Barrier, Microbial Translocation, and Immune Activation Biomarkers in Women With and Without HIV

Article

Jun 2024
JAIDS-J ACQ IMM DEF

Objectives Estrogens may protect the gut barrier and reduce microbial translocation and immune activation, which are prevalent in HIV infection. We investigated relationships of the menopausal transition and estrogens with gut barrier, microbial translocation, and immune activation biomarkers in women with and without HIV. Design Longitudinal and cross-sectional studies nested in the Women’s Interagency HIV Study. Methods Intestinal fatty acid binding protein (IFAB), lipopolysaccharide binding protein (LBP), and soluble CD14 (sCD14) levels were measured in serum from 77 women (43 with HIV) before, during, and after the menopausal transition (∼6 measures per woman over ∼13 years). A separate cross-sectional analysis was conducted among 72 post-menopausal women with HIV with these biomarkers and serum estrogens. Results Women in the longitudinal analysis were a median age of 43 years at baseline. In piece-wise linear mixed-effects models with cut-points 2 years before and after the final menstrual period to delineate the menopausal transition, sCD14 levels increased over time during the menopausal transition (Beta [95% CI]=38 [12, 64] ng/mL/year, p=0.004), followed by a decrease post-transition (-46 [-75, -18], p=0.001), with the piece-wise model providing a better fit than a linear model (p=0.0006). In stratified analyses, these results were only apparent in women with HIV. In cross-sectional analyses among women with HIV, free estradiol was inversely correlated with sCD14 levels (r=-0.26, p=0.03). LBP and IFAB levels did not appear related to the menopausal transition and estrogen levels. Conclusion Women with HIV may experience heightened innate immune activation during menopause, possibly related to depletion of estrogens.

Alcohol intake and endogenous sex hormones in women: Meta‐analysis of cohort studies and Mendelian randomization

Article

Full-text available

Jun 2024
CANCER-AM CANCER SOC

Background The mechanisms underlying alcohol‐induced breast carcinogenesis are not fully understood but may involve hormonal changes. Methods Cross‐sectional associations were investigated between self‐reported alcohol intake and serum or plasma concentrations of estradiol, estrone, progesterone (in premenopausal women only), testosterone, androstenedione, dehydroepiandrosterone sulfate, and sex hormone binding globulin (SHBG) in 45 431 premenopausal and 173 476 postmenopausal women. Multivariable linear regression was performed separately for UK Biobank, European Prospective Investigation into Cancer and Nutrition, and Endogenous Hormones and Breast Cancer Collaborative Group, and meta‐analyzed the results. For testosterone and SHBG, we also conducted Mendelian randomization and colocalization using the ADH1B (alcohol dehydrogenase 1B) variant (rs1229984). Results Alcohol intake was positively, though weakly, associated with all hormones (except progesterone in premenopausal women), with increments in concentrations per 10 g/day increment in alcohol intake ranging from 1.7% for luteal estradiol to 6.6% for postmenopausal dehydroepiandrosterone sulfate. There was an inverse association of alcohol with SHBG in postmenopausal women but a small positive association in premenopausal women. Two‐sample randomization identified positive associations of alcohol intake with total testosterone (difference per 10 g/day increment: 4.1%; 95% CI, 0.6–7.6) and free testosterone (7.8%; 4.1–11.5), and an inverse association with SHBG (–8.1%; –11.3% to –4.9%). Colocalization suggested a shared causal locus at ADH1B between alcohol intake and higher free testosterone and lower SHBG (posterior probability for H4, 0.81 and 0.97, respectively). Conclusions Alcohol intake was associated with small increases in sex hormone concentrations, including bioavailable fractions, which may contribute to its effect on breast cancer risk.

SHBG Gene Polymorphisms and Their Influence on Serum SHBG, Total and Free Testosterone Concentrations in Men

Article

Apr 2024
J CLIN ENDOCR METAB

Context Genetic variation in SHBG structure may affect estimates of sex steroid exposure by altering the affinity of the protein for its ligand. Consequently, free hormone calculations assuming constant binding affinity may, for certain genetic variations, lead to incorrect diagnoses if genetic variation is not taken into consideration. Objective To investigate the effects of genetic variation in SHBG on calculated and measured serum free testosterone (T) in men. Design, setting and participants Population-based sibling-pair study in 999 healthy men aged 25 to 45 (mean, 34.5) years. Main outcome measures Genotyping using microarray (Illumina) for single-nucleotide polymorphism (SNPs) suggested to affect binding affinity and/or concentration of SHBG or T. SHBG concentrations were measured using immunoassay and in a subset (n = 32) by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Total T was measured using LC-MS/MS. Free T was calculated and in a subset (n = 314) measured directly using LC-MS/MS after equilibrium dialysis. Results Allelic frequencies of analyzed SNPs ranged from 0.5% to 58.2%. Compared to wild-type, SHBG concentrations were lower in rs6258 heterozygotes (−24.7%; P < .05) and higher in rs6259 heterozygotes, rs727428 homozygotes, and carriers of rs1799941 (+10.8 to 23.1%; all P < .05). Total T was higher in rs727428 homozygotes and carriers of rs5934505, rs1799941and rs6259 (+3.9 to 21.4%; all P < .05). No clear effects on measured free T were found, except for a trend toward higher values in rs6259 homozygotes, significant for calculated free T (+18.7%; P < .05) in the larger global study population. Conclusion In these men, analyzed SNPs were relatively prevalent and affected serum concentrations of total T and SHBG but not calculated or measured free T except for a higher trend in rs6259 homozygotes.

Association between sex hormones and gout: An analysis of the UK Biobank cohort

Article

Apr 2024
STEROIDS

Sex Hormones and Abdominal Muscle Area and Radiodensity in Men: The Multi-Ethnic Study of Atherosclerosis

Preprint

Full-text available

Jan 2024

Information on the associations of testosterone levels with abdominal muscle volume and quality in men is limited, while the role of estradiol and SHBG on these muscle characteristics are unclear. To investigate the association between fasting serum sex hormones and CT-derived abdominal muscle area and radiodensity in adult men. Cross sectional observational study using data from the Multi-Ethnic Study of Atherosclerosis. A community-based sample of 907 men aged 45–84 years; 878 men with complete data were included in the analysis. CT scans of the abdomen were interrogated for muscle characteristics. Multivariable linear regressions were used to test the associations. After adjustment, higher levels of both total testosterone and estradiol were associated with higher abdominal muscle area (1.79, 0.1–3.4, & 1.79, 0.4–3.2, respectively). In the final analyses, levels of total testosterone showed a positive association, while an inverse relationship was observed for SHBG with abdominal muscle radiodensity (0.3, 0.0–0.6, & -0.34, -0.6 - -0.1, respectively). Our results indicate a complex association between sex hormones and abdominal muscle characteristics in men. Specifically, total testosterone and estradiol were associated with abdominal muscle area, while only total testosterone was associated with muscle radiodensity and SHBG was inversely associated with muscle radiodensity.

Interactions of obesity, body shape, diabetes and sex steroids with respect to prostate cancer risk in the UK Biobank cohort

Article

Full-text available

Jan 2024

Background Obesity and diabetes are associated inversely with low‐grade prostate cancer risk and affect steroid hormone synthesis but whether they modify each other's impact on prostate cancer risk remains unknown. Methods We examined the independent associations of diabetes, body mass index (BMI), ‘a body shape index’ (ABSI), hip index (HI), circulating testosterone, sex hormone binding globulin (SHBG) (per one standard deviation increase) and oestradiol ≥175 pmol/L with total prostate cancer risk using multivariable Cox proportional hazards models for UK Biobank men. We evaluated multiplicative interactions ( p MI ) and additive interactions (relative excess risk from interaction ( p RERI ), attributable proportion ( p AR ), synergy index ( p SI )) with obese (BMI ≥30 kg/m ² ) and diabetes. Results During a mean follow‐up of 10.3 years, 9417 incident prostate cancers were diagnosed in 195,813 men. Diabetes and BMI were associated more strongly inversely with prostate cancer risk when occurring together ( p MI = 0.0003, p RERI = 0.032, p AP = 0.020, p SI = 0.002). ABSI was associated positively in obese men (HR = 1.081; 95% CI = 1.030–1.135) and men with diabetes (HR = 1.114; 95% CI = 1.021–1.216). The inverse associations with obesity and diabetes were attenuated for high‐ABSI ≥79.8 ( p MI = 0.022, p RERI = 0.008, p AP = 0.005, p SI <0.0001 obesity; p MI = 0.017, p RERI = 0.047, p AP = 0.025, p SI = 0.0005 diabetes). HI was associated inversely in men overall (HR = 0.967; 95% CI = 0.947–0.988). Free testosterone (FT) was associated most strongly positively in normal weight men (HR = 1.098; 95% CI = 1.045–1.153) and men with diabetes (HR = 1.189; 95% CI = 1.081–1.308). Oestradiol was associated inversely in obese men (HR = 0.805; 95% CI = 0.682–0.951). The inverse association with obesity was stronger for high‐FT ≥243 pmol/L ( p RERI = 0.040, p AP = 0.031, p SI = 0.002) and high‐oestradiol ( p RERI = 0.030, p AP = 0.012, p SI <0.0001). The inverse association with diabetes was attenuated for high‐FT ( p MI = 0.008, p RERI = 0.015, p AP = 0.009, p SI = 0.0006). SHBG was associated inversely in men overall (HR = 0.918; 95% CI = 0.895–0.941), more strongly for high‐HI ≥49.1 ( p MI = 0.024). Conclusions Obesity and diabetes showed synergistic inverse associations with prostate cancer risk, likely involving testosterone reduction for diabetes and oestrogen generation for obesity, which were attenuated for high‐ABSI. HI and SHBG showed synergistic inverse associations with prostate cancer risk.

Discrepancies in Four Algorithms for the Calculation of Free and Bioavailable Testosterone

Article

Nov 2023

To the Editor Testosterone (T) binds to sex hormone-binding globulin (SHBG) and albumin (Alb) to form SHBG-T and Alb-T (1). If total testosterone (TT) is low or SHBG concentration is altered, free testosterone (FT) is recommended (1). Bioavailable testosterone (BioT) including FT and Alb-T correlates with FT (1, 2). FT and BioT can be measured by equilibrium dialysis and ammonium sulfate [(NH4)2SO4] precipitation, respectively (1). FT and BioT can also be calculated using algorithms (1) described by Vermeulen (2), Sodergard (3), and Emadi-Konjin (4), or using the empirical equation by Morris (5). We aimed to determine which equation, based on our own TT and SHBG assays, generates results that are closer to our reference laboratory values before bringing the FT and BioT tests in house. Forty-nine sera with known FT (0.05 to 19.22 ng/dL, or 1.7 to 666.2 pmol/L) and BioT (1.2 to 542.0 ng/dL, or 0.04 to 18.80 nmol/L) were obtained from the reference laboratory, where FT and BioT were calculated using a proprietary algorithm and TT and SHBG were measured by a LC-MS/MS assay and an immunoassay, respectively. In our laboratory, TT was measured by an LC-MS/MS assay with an analytical measurement range of 2.0 to 2330.4 ng/dL or 0.07 to 80.80 nmol/L, and interassay coefficient of variation of 4.7%, 2.6% and 2.4% at 3.2, 868.0, 1851.4 ng/dL, respectively. SHBG was measured by an immunoassay (Roche Diagnostics) with an analytical measurement range of 2 to 200 nmol/L, and interassay coefficients of variation of 1.8%, 2.1%, and 4.0% at 14.9, 45.7, and 219 nmol/L, respectively.

Prediagnostic Hormone Levels and Risk of Testicular Germ Cell Tumors: A Nested Case–Control Study in the Janus Serum Bank

Article

Aug 2023

Background: It has been hypothesized that poorly functioning Leydig and/or Sertoli cells of the testes, indicated by higher levels of serum gonadotropins and lower levels of androgens, are related to the development of testicular germ cell tumors (TGCTs). To investigate this hypothesis, we conducted a nested case-control study within the Janus Serum Bank cohort. Methods: Men who developed TGCT (n=182) were matched to men who did not (n=364). Sex steroid hormones were measured using liquid chromatography-mass spectrometry. Sex hormone binding globulin (SHBG), follicle stimulating hormone (FSH), and luteinizing hormone (LH) were quantified by direct immunoassay. Multivariable logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for associations between hormone levels and TGCT risk. Results: Higher FSH levels (tertile [T] 3 vs T2: OR=2.89, 95%CI=1.83-4.57) were associated with TGCT risk, but higher LH levels were not (OR=1.26, 95%CI=0.81-1.96). The only sex steroid hormone associated with risk was androstane-3α, 17β-diol-3G (3α-diol-3G) (OR=2.37, 95%CI=1.46-3.83). Analysis by histology found that increased FSH levels were related to seminoma (OR=3.55, 95%CI=2.12-5.95) but not nonseminoma (OR=1.19, 95%CI=0.38-3.13). Increased levels of 3α-diol-3G were related to seminoma (OR=2.29, 95%CI=1.35-3.89) and nonsignificantly related to nonseminoma (OR=2.71, 95%CI=0.82-8.92). Conclusions: Higher FSH levels are consistent with the hypothesis that poorly functioning Sertoli cells are related to the development of TGCT. In contrast, higher levels of 3α-diol-3G do not support the hypothesis that insufficient androgenicity is related to risk of TGCT. Impact: Clarifying the role of sex hormones in the development of TGCT may stimulate new research hypotheses.

Steroid determination—Sample preparation

Chapter

Jan 2023

John Honour

Utility and Limitations in Measuring Testosterone

Chapter

Jul 2023

Mathis Grossmann

Measurement of serum testosterone is essential to confirm a clinical suspicion of male androgen deficiency. Serum testosterone should be measured in the morning, in the fasted state in a medically stable patient without current or recent acute illness. A low serum testosterone should be confirmed. If the serum testosterone is repeatedly low, a tailored work-up is necessary to determine the cause of hypogonadism. Serum testosterone should be measured by a validated assay, and mass spectrometry-based assays are considered gold standard. While total testosterone is the primary measure to determine androgen status, in certain situations, measurement of sex hormone binding globulin and of free testosterone (ideally by gold standard equilibrium dialysis) can be helpful. In contrast, the utility of measuring the testosterone metabolites estradiol and dihydrotestosterone requires further research.KeywordsTestosteroneHypogonadismAndrogen deficiencyTestosterone assayLCMS-MSDihydrotestosteroneEstradiol

The association of hysterectomy with or without ovarian conservation with subclinical atherosclerosis progression in healthy postmenopausal women

Article

May 2023
MENOPAUSE

Objective: While the deleterious associations of surgical menopause after bilateral oophorectomy with cardiovascular disease are documented, less is specifically known concerning subclinical atherosclerosis progression. Methods: We used data from 590 healthy postmenopausal women randomized to hormone therapy or placebo in the Early versus Late Intervention Trial with Estradiol (ELITE), which was conducted from July 2005 to February 2013. Subclinical atherosclerosis progression was measured as annual rate of change in carotid artery intima-media thickness (CIMT) over a median 4.8 years. Mixed-effects linear models assessed the association of hysterectomy and bilateral oophorectomy compared with natural menopause with CIMT progression adjusted for age and treatment assignment. We also tested modifying associations by age at or years since oophorectomy or hysterectomy. Results: Among 590 postmenopausal women, 79 (13.4%) underwent hysterectomy with bilateral oophorectomy and 35 (5.9%) underwent hysterectomy with ovarian conservation, a median of 14.3 years before trial randomization. Compared with natural menopause, women who underwent hysterectomy with and without bilateral oophorectomy had higher fasting plasma triglycerides while women who underwent bilateral oophorectomy had lower plasma testosterone. The CIMT progression rate in bilaterally oophorectomized women was 2.2 μm/y greater than natural menopause (P = 0.08); specifically, compared with natural menopause, the associations were significantly greater in postmenopausal women who were older than 50 years at the time of bilateral oophorectomy (P = 0.014) and in postmenopausal women who underwent bilateral oophorectomy more than 15 years before randomization (P = 0.015). Moreover, the CIMT progression rate in hysterectomized women with ovarian conservation was 4.6 μm/y greater than natural menopause (P = 0.015); in particular, compared with natural menopause, the association was significantly greater in postmenopausal women who underwent hysterectomy with ovarian conservation more than 15 years before randomization (P = 0.018). Conclusions: Hysterectomy with bilateral oophorectomy and ovarian conservation were associated with greater subclinical atherosclerosis progression relative to natural menopause. The associations were stronger for later age and longer time since oophorectomy/hysterectomy. Further research should continue to examine long-term atherosclerosis outcomes related to oophorectomy/hysterectomy.

Statin therapy and sex hormones

Chapter

Jan 2023

Visceral Adipose Tissue is Negatively Associated with Bone Mineral Density in NHANES 2011-2018

Article

Full-text available

Jan 2023

Context The relationship of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) with bone mineral density (BMD) is not well established. Objective To examine the associations of VAT and SAT with total body BMD in a large, nationally representative population with a wide range of adiposity. Methods We analyzed 10,641 subjects aged 20-59 in NHANES 2011-2018 who had undergone total body BMD and had VAT and SAT measured by DXA. Linear regression models were fitted while controlling for age, gender, race or ethnicity, smoking status, height, and lean mass index. Results In a fully adjusted model, each higher quartile of VAT was associated with an average of 0.22 lower T-score (95% CI -0.26 - -0.17, p < 0.001), while SAT had a weak association with BMD but only in men (-0.10, 95% CI -0.17 - -0.04, p = 0.002). However, the association of SAT to BMD in men was no longer significant after controlling for bioavailable sex hormones. In subgroup analysis, we also found differences in the relationship of VAT to BMD in Black and Asian subjects, but these differences were eliminated after accounting for racial and ethnic differences in VAT norms. Conclusions Visceral adipose tissue has a negative association with BMD. Further research is needed to better understand the mechanism of action and, more generally, to develop strategies for optimizing bone health in obese subjects.

Associations of Sex-related Steroid Hormones and Proteins with Alcohol Dependence: a United Kingdom Biobank Study

Article

Mar 2023
DRUG ALCOHOL DEPEN

Background: Sex-related steroid hormones and proteins may contribute to the sex differences in the characteristics and health consequences of alcohol use disorder. This study aimed to examine the associations between alcohol dependence (AD) and sex-related hormones/proteins using a population-based dataset. Methods: We retrieved serum total testosterone (TT) and estradiol (TE2), sex hormone binding globulin (SHBG), and albumin levels along with clinical data from the UK Biobank. Hormone/protein levels were compared between AD (lifetime AD and/or related diagnoses; 2218 males; 682 females) and control (no aforementioned diagnoses and AUDIT<8; 198,058 males; 250,830 females) groups with sex-dependent linear regression models adjusting for age and body mass index. Moderation and mediation analyses were performed to test whether SHBG was a moderator and/or mediator between hormones and AD or current drinking. Results: AD males had higher TT, TE2, and SHBG levels but lower bioavailable testosterone, bioavailable estradiol, and albumin levels than controls (padjusted<0.001). After adjusting for menopause, AD females had higher TT and lower albumin levels than controls (padjusted<0.001). These differences remained after accounting for current drinking frequency (p < 0.001). SHBG moderated TT's effect on AD in males (pinteraction<0.001). SHBG was a positive mediator between TT and AD in both sexes and between TE2 and AD in males (p < 0.001), but a negative mediator between TT and current drinking in controls (both sexes) and AD males (p < 0.001). Conclusions: Testosterone and estradiol levels are altered in males and females with AD distinctly regardless of current drinking frequency. SHBG may play a critical role in these associations.

Associations between endogenous sex hormone levels and adipokine levels in the Multi-Ethnic Study of Atherosclerosis

Article

Full-text available

Jan 2023

Background Differences in sex hormone levels contribute to differences in cardiovascular disease (CVD) risk. Adipokines play a role in cardiometabolic pathways and have differing associations with CVD. Adipokine levels differ by sex; however, the association between sex hormone profiles and adipokines is not well established. We hypothesized that a more androgenic sex hormone profile would be associated with higher leptin and resistin and lower adiponectin levels among postmenopausal women, with the opposite associations in men. Methods We performed an analysis of 1,811 adults in the Multi-Ethnic Study of Atherosclerosis who had both sex hormones and adipokines measured an average of 2.6 years apart. Sex hormones [Testosterone (T), estradiol (E2), sex hormone binding globulin (SHBG), and dehydroepiandrosterone (DHEA)] were measured at exam 1; free T was estimated. Serum adipokines (leptin, resistin, adiponectin) were measured at exams 2 or 3. We used multivariable linear regression to examine the cross-sectional associations between sex hormones and adipokines. Results The mean (SD) age was 63 (10) years, 48% were women; 59% non-White participants. For leptin, after adjusting for demographics only, higher free T and lower SHBG, were associated with higher leptin in women; this association was attenuated after further covariate adjustment. However in men, higher free T and lower SHBG were associated with greater leptin levels in fully adjusted models. For adiponectin, lower free T and higher SHBG were associated with greater adiponectin in both women and men after adjustment for CVD risk factors. For resistin, no significant association was found women, but an inverse association with total T and bioT was seen in men. Conclusion Overall, these results further suggest a more androgenic sex profile (higher free T and lower SHBG) is associated with a less favorable adipokine pattern. These findings may provide mechanistic insight into the interplay between sex hormones, adipokines, and CVD risk.

Endogenous Steroid Hormone Concentrations and Risk of Endometriosis in the Nurses’ Health Study II

Article

Dec 2022
AM J EPIDEMIOL

Few studies have assessed endogenous steroid hormone levels and subsequent endometriosis diagnosis. We prospectively evaluated premenopausal plasma sex hormone levels and the risk of laparoscopically-confirmed endometriosis in a nested case-control study within the Nurses’ Health Study II. Between blood collection (1996-1999) and 2009, we ascertained 446 women with incident endometriosis and matched them to 878 controls through risk-set sampling. We conducted multivariable conditional logistic regression accounting for matching and confounders to estimate relative risks (RR) and 95% confidence intervals (CI). Women with greater early follicular total or free estradiol levels had a non-linear increased risk of endometriosis (early follicular total estradiol: 2nd quartile vs 1st, RR=2.23(CI=1.44-3.47); 3rd quartile, RR=1.83(CI=1.16-2.88); 4th quartile, RR=1.68(CI=1.05-2.68); early follicular free estradiol: 2nd quartile vs 1st, RR=1.63(CI=1.05-2.54); 3rd quartile, RR=2.02(CI=1.31-3.12); 4th quartile, RR=1.04(CI=0.66-1.65)). Free testosterone assessed in quartile categories was not associated with endometriosis, although a threshold effect was observed with a positive association among women in the top 2% of free testosterone levels. Mid-luteal total and free estradiol, follicular and luteal estrone, total testosterone, progesterone, and sex hormone binding globulin levels were not associated with endometriosis risk. These results support the role of sex steroids in endometriosis etiology, although the relationships suggest complex threshold effects.

Androgens impact on psychopathological variables according to CPRS, and EDI 2 scores: In women with bulimia nervosa, and eating disorder not otherwise specified

Article

Nov 2022
J STEROID BIOCHEM

Bulimia nervosa (BN) is characterized by binge eating, compensatory behavior, over-evaluation of weight and shape, which often co-occur with symptoms of anxiety and depression. Depression is the most common comorbid diagnosis in women with eating disorders. The role of androgens in the pathophysiology of depression has been recognized in recent years. However, the research on psychopathological comorbidity and androgen levels in bulimic disease is sparse. This study aimed to investigate, if there were any correlations between the androgens, testosterone (T), dehydroepiandrosterone sulphate (DHEAS), androstenedione (A4), 5α-dihydrotestosterone, (5α-DHT), and test scores of psychopathological variables, in women with bulimia nervosa (BN), eating disorder not otherwise specified of purging subtype (EDNOS-P) assessed by CPRS, and EDI 2. Women with DSM-IV diagnosis of BN (n = 36), EDNOS-P (n=27), and healthy control subjects (n=58) evaluated for fifteen psychopathological variables, i.a. depressive symptoms, impulsivity, personal traits, as well as serum androgen levels. All women were euthyroid, and polycystic ovarian syndrome (PCOS) diagnosis was excluded. Although androgen levels were almost equal for all three groups, significant correlations between core psychopathological symptoms (9/15) of bulimia nervosa and the most potent endogenous androgen, 5α-DHT, was found only in the EDNOS-P group. The role of 5α-DHT in women is not fully elucidated. Both animal and human studies have shown that the brain is able to locally synthesize steroids de novo and is a target of steroid hormones. Maybe these results can be interpreted in the light of differences in androgen receptor variability, metabolism and origin of T and 5α-DHT.

Parity History and Later Life Sex Hormone Levels in the Multi-Ethnic Study of Atherosclerosis (MESA)

Article

Sep 2022
CAN J CARDIOL

Background Multiparity is a risk factor for cardiovascular disease (CVD). A more androgenic sex hormone profile, with a higher testosterone/estradiol (T/E2) ratio, is associated with worse CVD outcomes in women and may be one mechanism linking multiparity to increased CVD risk. We investigated the relationship between parity and sex hormones at mid-to-older age. Methods We performed a cross-sectional analysis of 2,979 women with data on parity and endogenous sex hormone levels from MESA, a community-based cohort. Parity and gravidity (our exposures) were categorized as 0 (reference), 1-2, 3-4, or ≥5. Our outcome measures were testosterone (T), estradiol (E2), sex-hormone binding globulin (SHBG), dehydroepiandrosterone (DHEA), and T/E2 ratio. Progressively-adjusted linear regression was used to evaluate the association of parity/gravidity with sex hormones. Results In multivariable-adjusted models, there were no significant associations of parity with E2, DHEA, and SHBG. Compared to nulliparity, after adjustment for CVD risk factors, women with 1-2 and 3-4 live births had higher T, but this was not significant for grand multiparity (≥5 live births). However, grand multigravidity (≥5 pregnancies) was associated with 10% (95% CI: 1%, 20%) higher T and 14% (1%, 29%) higher T/E2, compared to null-gravidity. Grand multiparity was associated with an 18% (4%, 34%) higher T/E2 ratio compared to nulliparity, after adjustment for CVD risk factors. Conclusions In this multiethnic cohort, women with grand multigravidity and grand multiparity had higher T/E2 levels, reflecting a more androgenic sex hormone profile. Longitudinal studies evaluating sex hormones’ influence on the relationship between multiparity and CVD are warranted.

Androgens in postmenopausal women

Article

Aug 2022

Key content Androgen therapy can improve sexual wellbeing, libido and sexual arousal in postmenopausal women through its effect on the central nervous system. Testosterone levels gradually decline throughout a woman’s lifespan and testosterone therapy may be useful for menopausal women with sexual dysfunction, in whom estrogen therapy alone has been ineffective. Learning objectives To understand the physiology and the potential impact of changes in testosterone levels in postmenopausal women. To be aware of the potential role of androgen therapy in postmenopausal women with low sexual desire causing distress. To review the available evidence behind the use of androgen therapy for female sexual dysfunction in the menopause. Ethical issues More women are spending a greater proportion of their lives in the postmenopausal period, so it is important to gain a greater understanding of the role of testosterone replacement after the menopause in improving sexual dysfunction. Off‐label use of testosterone gels and creams is common; when prescribing these, clinicians must inform women of the potential benefits and risks as well as the fact that long‐term safety data is still lacking.

Association of the vitamin D and parathyroid hormone status with the ageing‐related decline of bone microarchitecture in older men – the prospective STRAMBO study

Article

Jul 2022

Poor vitamin D status and high parathyroid hormone (PTH) level are associated with impaired bone microarchitecture, but these data are mainly cross‐sectional. We studied the association of the baseline PTH and 25‐hydroxycholecalciferol (25OHD) levels with the prospectively assessed deterioration of bone microarchitecture and in estimated bone strength in older men. Distal radius and tibia bone microarchitecture was assessed by high resolution peripheral quantitative computed tomography (HR‐pQCT) at baseline, then after 4 and 8 yrs in 826 men aged 60‐87. At distal radius, total bone mineral density (Tt.BMD), cortical thickness (Ct.Thd), cortical area (Ct.Ar), cortical BMD (Ct.BMD) and trabecular BMD (Tb.BMD) decreased, whereas trabecular area (Tb.Ar) increased more rapidly in men with 25OHD≤20ng/mL vs. the reference group (>30ng/mL). Men with 25OHD≤10ng/mL had faster decrease in reaction force and failure load than men with 25OHD>30ng/mL. At the distal tibia, Tt.BMD, Ct.Thd, Ct.Ar, Ct.BMD, failure load and reaction force decreased, whereas Tb.Ar increased more rapidly in men with 25OHD between 10 and 20 ng/mL versus the reference group. The results were similar when 12ng/mL was used as a threshold of severe vitamin D deficiency. At distal radius, men with PTH levels above the median (>44pg/mL) had more rapid decrease in Tt.BMD, Ct.Ar, Ct.BMD, Ct.Thd, reaction force and failure load, and more rapid increase in Tb.Ar vs. the lowest quartile (≤34pg/mL). At the distal tibia, men in the highest PTH quartile had faster decrease in Tt.BMD, Ct.Thd, Ct.Ar, Ct.BMD, reaction force, and failure load and faster increase in Tb.Ar versus the lowest quartile. The results were similar in men with glomerular filtration rate >60mL/min. The results were similar in men who took no vitamin D or calcium supplements for 8 years. In summary, vitamin D deficiency and secondary hyperparathyroidism are associated with more rapid prospectively assessed cortical and trabecular bone decline in older men. This article is protected by copyright. All rights reserved.

Isolation and characterization of the testosterone-estradiol-binding globulin from human plasma. Use of a novel affinity column

Article

Full-text available

Dec 1975

This report concerns the purification and characterization of the testosterone-estradiol-binding globulin (TeBG) from human plasma. Cohn fraction IV was submitted sequentially to ammonium sulfate preciptation, affinity chromatography, gel filtration, and isoelectric focusing. The final product was homogeneous in polyacrylamide gel electrophoresis and sodium dodecyl sulfate gel electrophoresis. Its activity was demonstrated by the finding of slightly more than one binding site/mole for dihydrotestosterone. Association constants (M-1) at 4 and 37degreesC were ascertained for three steroids: dihydrotestosterone; 2.4 x 10(9) and 0.99 x 10(9); testosterone, 1.1 x 10(9) and 0.35 x 10(9); estradiol, 0.60 x 10(9) and 0.22 x 10(9). TeBG is a glycoprotein having a molecular weight of 94000 and both the amino acid and carbohydrate content are presented along with other physical properties.

A Further Study of a Testosterone-binding Component of Human Pregnancy Serum

Article

Full-text available

Apr 1969

Equilibrium constants of association were determined by a technique based on the principle of equilibrium dialysis but utilizing Sephadex G-25 for the strong binding exhibited by human pregnancy serum (or by the material precipitated from late pregnancy serum by ammonium sulfate at 50% saturation) for: (a) testosterone-1,2-³H, (b) radioinert 17β-estradiol (in competition with testosterone-1,2-³H), and (c) 17β-estradiol-6,7-³H. The respective values for the intrinsic association constant, k, were all quite high: (a) 4.5 × 10⁸M⁻¹, (b) 1.35 × 10⁸M⁻¹, and (c) 0.4 × 10⁸M⁻¹. These findings are in accord with the view that the testosterone-binding component of pregnancy serum also binds 17β-estradiol but not as strongly. The binding of 17β-estradiol by bovine serum albumin, measured by the same technique, gave nk = 9 × 10⁴M⁻¹. Reagents which react with —SH groups, and other reagents which reduce the disulfide bonds, depressed in striking fashion the testosterone-binding activity of pregnancy serum. It is suggested that the testosterone-binding component contains both cysteine and cystine, and that their maintenance intact is important for steroid-binding activity.

Steroid-Protein Interaction with Particular Reference to Testosterone Binding by Human Serum

Article

Full-text available

Feb 1967

The binding affinity of serum protein for testosterone (and also of serum albumin as a reference protein) was determined by a technique based on the principle of equilibrium dialysis but with the use of the cross-linked dextran, Sephadex G-25, in a batchwise fashion on a semimicro scale. The binding parameters were shown to be dependent on the concentrations of both protein and steroid. The logarithm of the reciprocal of the protein concentration and the logarithm of the reciprocal of the bound steroid concentration (at 50% steroid binding) were in linear relationship. A sensitive and rapid method thus evolved for the detection and quantitative estimation of serum protein, or proteins, exhibiting a specific or high binding affinity for testosterone. This new technique, entailing a novel treatment of the experimental data, may also prove to be useful in the general study of steroid-protein interaction. Testosterone-binding levels in various human sera were determined in a comparative survey; markedly elevated levels were observed in advanced pregnancy.

The attractions of proteins for small molecules and ions

Article

G. Scatchard

Secretion rates of androgens in human subjects

Article

Jan 1969

A. Vermeulen

Multiple Equilibria in Proteins, Molecular Biology

Article

Jan 1969

A paper chromatographic saturation analysis method for measuring estradiol, testosterone and 5alpha-dihydrotestosterone from the same sample

Article

Jan 1976
J STEROID BIOCHEM

Protein-Steroid Interactions and Their Role in the Transport and Metabolism of Steroids

Chapter

Dec 1966

Steroid-protein interactions Complex formation between aj-acid glycoprotein and steroid hormones

Article

Jan 1968
BBA-GEN SUBJECTS

Applied Numerical Analysis

Article

Jan 1978

C.F. Gerald

Capacity of the Testosterone-Binding Globulin in Human Plasma and Influence of Specific Binding of Testosterone on Its Metabolic Clearance Rate

Article

Nov 1969

The binding capacity (TeBC) and binding index (BI) of the testosterone-binding globulin (TeBG) have been studied in several groups of patients. Before puberty, TeBC and BI are similar in both sexes and in the adult female range, but are higher in adult females than in adult males. Increased. TeBC and BI values were observed in male hypogonadism in hyperthyroidism, and in males with chronic asthmatic bronchitis or cirrhosis of the liver. During pregnancy increased TeBC and BI values were observed but at delivery low normal TeBC and BI values were found. Decreased TeBC and BI values were observed in hirsutism, in female obese patients, and in patients with the nephrotic syndrome. Progestogens do not increase TeBC, whereas estrogens (contraceptives) increase significantly the TeBC and BI values; decreased values were observed after testosterone treatment of females; corticoids decrease the TeBC values of patients with chronic asthmatic bronchitis. The metabolic clearance rate (MCR) of testosterone, ...

The Attraction of Proteins for Small Molecules and Ions

Article

Dec 2006
ANN NY ACAD SCI

George Scatchard

Calcium, Phosphate and Albumin in Serum

Article

Jan 1977

ABSTRACT Serum values for calcium, phosphate and albumin have been determined in a population study of 2 322 49–50-year-old men participating in a health examination survey. Calcium and albumin were significantly correlated (r=0.34) but adjustment for albumin only caused minor effects on the distribution of calcium. No inverse relationship was found between calcium and phosphate. Seasonal variations over the three years of the health survey could not be established for either calcium or phosphate, whereas there was a slight tendency for albumin to decline during summer. The prevalence of hyperparathyroidism (HPT) in this population of men up to the age of 50 was 0.3% and among those with recurrent renal stones 5.3%. All subjects with verified HPT had a history of recurrent renal stones. One man on thiazide treatment had a slight elevation of calcium which returned to normal after cessation of the drug. No other case of hypercalcemia besides those caused by HPT was found. Mean values and frequency distributions for calcium, phosphate and albumin were almost identical in renal stone formers and matched controls. Hence it seems likely that other factors than those which markedly affect serum levels of calcium and phosphate are of major importance in common renal stone formation.

Studies on the Protein Binding of Dihydrotestosterone in Human Plasma in Different Physiological Conditions and Effect of Medroxyprogesterone

Article

Feb 1972
STEROIDS

The binding of dihydrotestosterone (DHT) by plasma proteins has been studied by equilibrium dialysis. The effects of time, temperature, pH and dilution are given. The binding of DHT is higher than that of testosterone (T). It has a sex difference in adults, but not in children, and it is increased by estrogens.The apparent association constant (KDHT) of testosterone estradiol binding globulin (Te BG) was estimated, and found identical in children and females (K 37° C: 1.21 to 1.3 × 109 L/M). In contrast the capacity of children plasma was higher than that of adult females. The K 37° C for albumin was similar for human and bovine albumin (KA: 1.5 and 1.6 × 104 L/M).Medroxyprogesterone decreases significantly the percentages binding of T and DHT in girls.

Study of steroid-protein binding by means of competitive adsorption: Application to Cortisol binding in plasma

Article

Dec 1967
CLIN CHIM ACTA

The distribution of a steroid between a solution of steroid-binding proteins and a steroid-adsorbing solid added to this solution, depends not only on the properties of the adsorbent but also on the properties of the binding proteins and thus may be used for the study of steroid-protein interactions. Different types of distribution can be distinguished and were applied to the study of cortisol binding in plasma. 1.(1) Endogenous steroids were removed from plasma by incubation with a rather large amount of adsorbent.2.(2) The cortisol-binding capacity of plasma transcortin was measured after incubation with a balanced amount of adsorbent and cortisol.3.(3) A relative index of cortisol-protein binding proportional to the ratio of bound to unbound cortisol, was determined by incubation of charcoal-treated plasma with a trace of [1,2-3H]cortisol and appropriate amounts of adsorbent.4.(4) From this relative index of cortisol—protein binding in plasma an estimate of the cortisol-binding affinity of plasma transcortin was derived.

Applied Numerical Analysis

Book

Jan 1994

The fifth edition of this book continues teaching numerical analysis and techniques. Suitable for students with mathematics and engineering backgrounds, the breadth of topics (partial differential equations, systems of nonlinear equations, and matrix algebra), provide comprehensive and flexible coverage of numerical analysis.

Methods of multiple steroid radioimmunoassay

Article

Feb 1975

Modifications of partition column chromatography techniques have allowed the simultaneous elution of 7 plasma steroids using celite columns 5 cm. in length. Utilizing specific antisera, blood levels of estradiol17β (E2), progesterone, 17-hydroxy-progesterone, testosterone, androstenedione, dehydroepiandrosterone (DHA) and 5α-dihydrotestosterone (DHT), have been determined in normal men and normal and hirsute women. The results are in close accord to steroid levels found by various investigators using other methods of analysis. The method has considerable advantage over published methods in its versatility and the need for only small blood samples for multiple steroid determinations.

Steroids and the practical aspects of performing binding studies

Article

Jun 1976

Many cellular regulatory processes are described by ligand interactions with macromolecules. Steroid complexing with specific cytoplasmic receptor proteins and the subsequent binding of these complexes to nuclear constituents are two such processes which are fundamental to the understanding of steroid hormone action. These reactions are characterized by the binding parameters k, the equilibrium association constant, and M0, the binding site molarity. The current methods used to determine these two parameters are discussed in relation to the general theory of binding parameter measurement. A number of practical aspects of binding parameter measurement are considered. These include problems encountered by working at dilute non-uniform protein concentrations, non-specific binding, and the limitations of all such experimental systems. An exact solution to the non-linear Scatchard plot is presented for the case when only two non-interacting classes of binding sites need be considered. Finally, a set of specific conclusions is offered which should enable investigators to obtain the most accurate information possible whenever carrying out steroid hormone or receptor binding studies.

Relative Binding of Testosterone and Estradiol to Testosterone-Estradiol-Binding Globulin*

Article

Jan 1980

The binding of estradiol (E2) and testosterone (T) to testosterone-estradiol-binding globulin (TeBG) was studied in vivo at 37 C by three independent methods: equilibrium dialysis, steady state polyacrylamide gel electrophoresis, and TeBG-ligand dissociation kinetics. Equilibrium dialysis was performed at 37 C with the dialysate containing human serum albumin in amounts equivalent to that of the plasma dialysand. Scatchard analysis indicated that under these conditions E2 does not measurably bind to TeBG, while T has a Kd of 3.7 X 10(-10) M. Similarly, Scatchard-type analysis of E2 binding to TeBG in steady state polyacryalmide gel electrophoresis at 37 C revealed no high affinity saturable binding, while dihydrotestosterone was bound with a Kd of 2.7 X 10(-10) M. Examination of the dissociation kinetics of T and E2 ffrom TeBG revealed that the mean (+/-SD) T1/2 of dissociation of T from plasma at 37 C (10.8 +/- 2.4 min) was significantly shortened to 3.5 +/- 0.4 min by saturation of plasma with dihydrotestosterone (P less than 0.01), whereas that of E2 (8.9 +/- 1.4 min) was not changed (9.6 +/- 3.0 min). These data suggest that TeBG is not an important binder of plasma E2 at physiological temperatures and explain the observation that in diseases characterized by high TeBG levels, such as hyperthyroidism and liver disease, the MCR and free E2 levels have generally been normal.

Calcium, phosphate and albumin in serum. A population study with special reference to renal stone formers and the prevalence of hyperparathyroidism in middle aged men

Article

Feb 1977
Acta Med Scand

Serum valuse for calcium, phosphate and albumin have been determined in a population study of 2322 49-50-year-old men participating in a health examination survey. Calcium and albumin were significantly correlated (r = 0.34) but adjustment for albumin only caused minor effects on the distribution of calcium. No inverse relationship was found between calcium and phosphate. Seasonal variations over the three years of the health survey could not be established for either calcium or phosphate, whereas there was a slight tendency for albumin to decline during summer. The prevalence of hyperparathyroidism (HPT) in this population of men up to the age of 50 was 0.3% and among those with recurrent renal stones 5.3%. All subjects with verified HPT had a history of recurrent renal stones. One man on thiazide treatment had a slight elevation of calcium which returned to normal after cessation of the drug. No other case of hypercalcemia besides those caused by HPT was found. Mean values and frequency distributions for calcium, phosphate and albumin were almost identical in renal stone formers and matched controls. Hence it seems likely that other factors than those which markedly affect serum levels of calcium and phosphate are of major importance in common renal stone formation.

Free and Protein-Bound Plasma Estradiol17 During the Menstrual Cycle

Article

Sep 1976

Methods are described for the measurement of the estradiol-binding capacity of TeBG and of the free, TeBG-bound, and non-specifically protein-bound fractions of plasma estradiol. Each determination used undiluted plasma at 37 C, and a total volume of less than 2.0 ml of plasma was required to complete all the assays. The measurement of the per cent of free estradiol was affected by changes in plasma dilution. The measurement of the other fractions of estradiol was not influenced by changes in either the dilution or the volume of plasma. The distribution of plasma estradiol was determined daily throughout 5 individual menstrual cycles. The per cent of free, the per cent of TeBG-bound, and the TeBG binding capacity of estradiol remained constant throughout the cycle with mean values of 2.21 +/- 0.04% (SE), 38.4 +/- 0.7%, and 16.6 +/- 0.43 ng/ml, respectively. The mean association constant of TeBG for estradiol was 6.58 +/- 0.25 x 10(7)M-1. The concentration of the free and non-specifically protein-bound fractions of estradiol paralleled the total plasma concentration of estradiol. The results show that biologic events related to normal cyclic changes of plasma estradiol may be attributed to fluctuations in the free estradiol and to estradiol which is bound with low affinity to non-specific plasma proteins.

Concentration of estradiol, testosterone and progesterone in cerebrospinal fluid compared to plasma unbound and total concentrations

Article

Jun 1976

Estradiol, progesterone and testosterone are measured in plasma and CSF in 17 women and 11 men. The results show a transfer from plasma to CSF of about 4% for estradiol, 10% for progesterone and 2.5% for testosterone. There was found to be a clear correlation between the plasma and CSF levels of these steroids. A comparison is also made between the calculated levels of unbound estradiol and testosterone in plasma and the levels in the CSF. The results show approximately the same concentrations of these steroids in the CSF as the calculated levels of unbound steroids in the plasma.

An assay for sex hormone binding globulin based on affinity chromatography

Article

Jan 1977
CLIN CHIM ACTA

Plasma dihydrotestosterone in normal adult males and its relation to testosterone

Article

Jul 1975
Acta Endocrinol

A radioimmunoassay for dihydrotestosterone (DHT) in plasma was developed using an antiserum raised against testosterone-3-oxime-bovine-serum-albumin. After extraction of 1 ml male plasma with diethylether, DHT was separated from testosterone (T) by thin-layer chromatography. A dextran-charcoal-suspension was used for the separation of bound and free ligand. The inter-assay variability was 10.4 % (C. V.) and the detection limit 1.77 ng/100 ml. The accuracy of the method as determined by mass recoveries and the specificity were shown to be satisfactory. Normal values were obtained in 45 young to middle-aged (22–61 years) and 37 old (68–93 years) men. The median and the 95 percentiles were 20.5– 51.9 –76.3 (ng/100 ml) and 19.5– 50.9 –101.5 (ng/100 ml) respectively. While DHT did not change in old age T fell by 20.6%. DHT and T showed a significant correlation: r S = 0.426, P < 0.01 (young men), r S = 0.752, P < 0.001 (old men). After 3 daily im injections of 5000 IU human chorionic gonadotrophin (HCG), DHT increased 1.50 times (range: 1.15–2.09, n = 12), T 1.86 times (range: 1.20–2.91, n = 12). After 4 daily administrations of 40 mg fluoxymesterone DHT fell to 29.6% of the control level (range: 16.0–48.2%, n = 12). Blood samples were obtained from a 24 year old man every 15 min for 24 h. A close parallelism was observed between the concentrations of DHT and T in the plasma.

Elevated free testosterone in the plasma of early pregnant women bearing male fetuses and of hypersexual men

Article

Aug 1975
Endokrinologie

Significantly elevated free testosterone plasma values were found in early pregnant women (weeks 7 to 10 of pregnancy) bearing male fetuses, as compared wih those bearing female fetuses, and in hypersexual men as compared with normosexual men.

A paper chromatographic saturation analysis method for measuring estradiol, testosterone and 5α-dihydrotestosterone from the same sample

Article

Mar 1976

A new method permitting the estimation of estradiol, testosterone and 5α-dihydrotestosterone in the same plasma sample is presented. This is made possible by a 20 h overflow paper chromatography system used to purify the plasma extract prior to steroid analysis. Estradiol is well separated from estrone as is testosterone from 5α-dihydrotestosterone. The method has low blank values, good agreement between duplicates, acceptable recovery through the extraction and purification and a good recovery of steroids added to plasma prior to extraction. Plasma levels of steroids measured using this method agree well with the values obtained by other methods.

Androstenediol Levels in Human Peripheral Plasma 1 2

Article

Jan 1973

Unconjugated androstenediol has been identified and measured in the plasma of normal adults. Identification of the steroid in ether extracts of plasma was based upon its affinity for “testosterone binding globulin,” chromatographic mobility before and after derivative formation, and identity after acetylation with carrier androstenediol diacetate upon recrystallization. By means of competitive protein binding analysis, peripheral plasma androstenediol levels were determined to be 68.2 ± 24 (sd) ng/100 ml in normal women, 124 ± 45 ng/100 ml in normal men. The androstenediol concentration in men averages twenty percent of the testosterone level, that of women is nearly twice their testosterone level. Since available data indicates that androstenediol is moderately androgenic, this steroid appears to contribute significantly to total androgenicity in women and may play a role in certain hyperandrogenic states.

Sex-Hormone-Binding Globulin is an Oestrogen Amplifier

Article

Dec 1972

WE suggest a novel biological role for a specific plasma-binding protein in the regulation of oestrogen and androgen activity in man. The biological activity of oestradiol and testosterone, as with other steroids1, is probably exerted by the unbound fraction in plasma; this is only 1-3% of the total concentration. The plasma proteins that bind testosterone and oestradiol include sex-hormone-binding β globulin (SHBG)2, which has high affinity for both steroids; and albumin, which has low affinity but is present in three thousand times the concentration. Further, corticosteroid-binding globulin (CBG) binds testosterone3 though its main affinity is for cortisol and progesterone.

Binding of 5 -androstane-3,17 -diol to human plasma proteins

Article

Jun 1973

The binding of 5α androstane 3α,17β diol to human plasma proteins was studied by equilibrium dialysis. The mean value of 96.6% for men was significantly less than that of 97.5% for women. These values are higher than those found for 5α dihydrotestosterone (95.0 and 97.3%, respectively) and for testosterone (92.4 and 95.3%, respectively). When the distribution of labeled steroid in the different protein fractions was studied by paper electrophoresis, male plasma showed a larger fraction of 5α androstane 3α,17β diol radioactivity in the albumin fraction and less in the β globulin area than did female plasma. Similar findings were made when 5α dihydrotestosterone was studied. No inter α globulin peak of radioactivity was found for 5α androstane 3α,17β diol and 5α dihydrotestosterone as occurs for testosterone. Albumin binds more 5α androstane 3α,17β diol than 5α dihydrotestosterone or testosterone when studied by equilibrium dialysis, and this is due to a higher apparent association constant between albumin and the dihydroxysteroid.

Studies on the binding of testosterone to human plasma

Article

Jun 1968
STEROIDS

Binding of testosterone by plasma proteins has been studied by equilibrium dialysis and Sephadex® filtration. Testosterone in human plasma is bound by albumin (K25°C = 2.38 × 104 liter per mole) and by a specific β globulin of limited capacity (capacity = 4 − 6 × 10−8 mole per liter) but high affinity (K25°C = 4 − 16 × 108). Binding capacity increases by estrogen treatment and pregnancy. The testosterone binding globulin is specific for steroids with a 17β hydroxylgroup; as a consequence it also binds oestradiol.

Testosterone, Androstenedione and Dehydroepiandrosterone in Plasma During Pregnancy and at Delivery: Concentration and Protein Binding

Article

Feb 1968

Pregnancy produces a significant (p <0.01) increase in the concentration of testosterone (T) in plasma (nonpregnant females 49 ±13; pregnant females 114 ±38 mμg/100 ml), a nonsignificant increase in the androstenedione (A) concentration (nonpregnant 181 ±59; pregnant 249 ±82 mμg/100 ml) and a nonsignificant decrease in the dehydroepiandrosterone (D) concentration (nonpregnant 502 ±88; pregnant 363 ±233 mμg/100 ml). There was no correlation between fetal sex and maternal concentration of T and D. Mothers bearing a male fetus tended to have Δ values higher than those of mothers bearing a female fetus; the difference, however, was not significant. At delivery, the plasma concentrations of Δ and D were significantly higher than those during pregnancy, while the plasma concentration of T was similar. In every instance, the concentrations of T, Δ and D in the plasma of cord vein were lower than those of the corresponding maternal plasma. There was no correlation between the sex of the newborn and the concentrations of the 3 androgens in the plasma of cord vein. Pregnancy significantly increased the percentage of T-binding and D-binding, but it did not change that of Δ-binding, when using equilibrium dialysis at 37 C, with diluted plasma samples.

Status of Estrogen-Androgen Balance in Hyperthyroid Men with Graves' Disease

Article

Mar 1974

The authors studied the serum concentrations of total testosterone (T), unbound T, dihydrotestosterone (DHT), total estradiol 17β (E2), unbound E2 and luteinizing hormone (LH) in 15 hyperthyroid men with Graves' disease, 4 of whom had gynecomastia. The mean serum T concentration of 1895 ng per 100 ml in hyperthyroid patients was significantly higher than the mean value of 621 in normal men. It could be explained by an increase in serum concentration of sex hormone binding globulin (SHBG) in hyperthyroidism; the mean serum unbound T, 21.9 ng per 100 ml, in hyperthyroid patients was not statistically different from the corresponding value of 17.3 in normal men. Serum DHT concentration was also elevated in hyperthyroid patients. Similarly, the mean serum E2, 10.8 ng per 100 ml, in hyperthyroid men, was significantly greater than the corresponding mean value of 2.7 in normal men. However, it could not be explained entirely by elevation of serum SHBG in hyperthyroidism. The average unbound E2 concentration, 135 pg per 100 ml, in patients under study, was also higher than the corresponding value of 55.6 in normal men; it was comparable to the mean value of 144 in normal women. The ratio of serum total E2 to (E2/T x 100) averaged 0.57 in hyperthyroid men, which did not differ significantly from the mean ratio of 0.43 in normal men. The mean ratio of unbound E2 and unbound T of 0.65 in hyperthyroid men was, however, significantly higher than that of 0.34 in normal men. The mean serum LH concentration was also elevated in hyperthyroid patients. The values of serum T, DHT and unbound T in presence of gynecomastia were not different from those in its absence. However, serum E2, unbound E2, unbound E2/T and LH were significantly higher in patients with gynecomastia than in those without it. It is proposed that alterations in balance between circulating unbound estrogen and unbound androgen may have a significant role in genesis of gynecomastia in hyperthyroidism, and that the combination of the findings of supranormal serum LH, elevated total E2, unbound E2, total T and a normal serum unbound T in hyperthyroid men may be a result of supranormal setting of hypothalamo hypophyseal gonadal axis, presumably due to enhanced production or effectiveness of hypothalamic luteinizing hormone releasing hormone (LHRH) in hyperthyroidism. Normal serum unbound T under these circumstances would suggest some limitation in testicular secretion of T in response to LH in patients with hyperthyroidism.

Plasma concentrations of free and non-TeBG bound T in women on oral contraceptives

Article

Jan 1975
CONTRACEPTION

PIP Differential precipitation of plasma proteins after equilibration of the plasma with tracer amounts of testosterone (T) was used to measure free and not-T-estradiol binding globulin (TeBG)-bound T in 20 women and 10 men. Tritiated T was the tracer used. Comparison of this method with the equilibration dialysis method produced a good agreement in accuracy. The method is described as simple and reproducible, allowing routine assay of 20 plasma samples in duplicate by 1 technician. Normal values for men were 497 ng/100 ml (total T), 42 ng/100 ml(free T), 137 ng/100 ml (non-TeBG bound), and .5 mcg/100 ml (TeBG). Women's values were 52 ng/100 ml (Total T), 2.6 ng/100 ml (free T), 5 ng/100 ml (nonTeBG) and .9 mcg/100 ml (TeBG). Significant increases in total (p less than .05), free (p less than .01), non-TeBG-bound (p less than .05), and TeBG-T (p less than .01) were found for women taking norethindrone and mestranol. Women taking norgestrel-ethinyl estradiol had significant increase (p less than .01) in non-TeBG-bound T. It is concluded that estrogens increase the binding capacity of TeBG, and this is inhibited by norgestrel.

Further Studies on Leydig Cell Function in Old Age

Article

Aug 1974

Pathophysiological mechanisms leading to a decreased Leydig cell function in old males were studied. Increased basal plasma LH and FSH levels, an increased pituitary reaction to LHRH 200 μg iv, and a decreased responsiveness of the Leydig cells to hCG (chorionic gonadotrophin) stimulation, lead to the conclusion that the decreased Leydig cell function in old age has a primary testicular origin. The plasma estrone and estradiol levels are slightly but significantly increased in elderly males; the free estradiol concentration is however unchanged. There exists a highly significant correlation between the (log transformed) apparent free testosterone concentration and LH and FSH levels, suggesting that the feedback of the gonadotropin secretion is regulated via the free rather than via total testosterone levels.

Kinetics of [3H]-testosterone metabolism in normal young men: Effects of medroxyprogesterone acetate (provera) administration

Article

Oct 1972

We studied the effects of oral medroxyprogesterone acetate (provera) administration on the kinetics of testosterone metabolism in normal young men. We investigated changes in the metabolic clearance rate, transport and metabolic rate constants, volumes of distribution, plasma levels, blood production rates and levels of binding to plasma proteins. In all subjects the plasma level and blood production rate for testosterone decreased during provera administration. When provera was administered for 5 days the metabolic clearance rate and volumes of distribution decreased. After 10 days of administration, the changes in the metabolic clearance rate were variable. In the 5 day studies, the levels of binding of testosterone to plasma proteins increased; they showed variable changes after 10 days.

Further studies on the temperature dependence of the binding of testosterone to human pregnancy plasma proteins

Article

Apr 1973
STEROIDS

The binding of testosterone by pregnancy plasma proteins has been studied by a new equilibrium dialysis system. The temperature dependence on the association constant has been investigated and the enthalpy change ΔH and entropy change ΔS have been calculated.By a computer optimization program, the binding constant of the high affinity testosterone binding protein has been estimated from Scatchard plots. The binding reactions were carried out at 5°, 25° and 37° C. The corresponding values were 3.1.10 1.2.109 and 7.2.108 liter/mole. The resulting enthalpy and entropy changes were −2.0 kcal/mole and 35.0 cal/(mole.degree) respectively.It can be concluded that the binding of testosterone to the specific binding protein is an exothermic reaction and is stabilized by hydrophobic binding forces.

The measurement of sex steroid binding globulin by differential ammonium sulphate precipitation

Article

Aug 1973

The binding parameters of the sex steroid binding globulin (SSBG) for testosterone and estradiol have been measured by a method using differential precipitation of plasma proteins by ammonium sulphate. The method is relatively simple and can be applied in a routine manner for the analysis of large numbers of plasma samples. The values for the binding capacity and association constant are similar to those reported for other methods. The method also enables the calculation of the circulating plasma levels of unbound steroids.

A New Method for the Determination of the Binding Capacity of Testosterone-Estradiol-Binding Globulin in Human Plasma

Article

Oct 1973

A new method for the quantitative determination of the testosterone-estradiol-binding-globulin, TeBG, in human plasma is described. The concentration of the globulin is measured in terms of the specific binding capacity in plasma for 5α-dihydrotestosterone, DHT. The method is based on equilibrium partition in an aqueous two-phase system containing 10% (w/w) dextran (Mw = 4 × 105), 7% (w/w) poly-(ethylene glycol) (Mn = 6 × 103), 0.1M KSCN in 0.005 M phosphate buffer. In this two-phase system more than 99% of the total plasma proteins partition into the lower phase and the partition coefficients for DHT and testosterone are 1.66 and 1.73 respectively. The concentration of the bound and unbound DHT or testosterone in equilibrium with the plasma proteins was determined from the concentration of the steroid in the upper phase. The method is rapid and simple and requires only small quantities of plasma. In contrast to those for testosterone, the results for the binding of DHT are not affected by the presence of transcortin and endogenous steroids in plasma. The intrinsic association constant for the binding of DHT and testosterone to TeBG and the apparent association constant for the binding to albumin were determined from Scatchard-type binding plots. The constants for DHT were 2.2 × 109 L mol−1 for TeBG and 8.6 × 104 L mol−1 for albumin. The affinity of TeBG for DHT was found to be about 2.4 times that for testosterone. The specific binding capacity values obtained, expressed as μg DHT bound/100 ml plasma, were: men, 1.76, women: 3.00; pregnant women, 12.7.

3α-Androstanediol in Human Peripheral Plasma

Article

Mar 1974

A radioimmunoassay for 3alpha androstanediol (3alpha diol) in human peripheral plasma is described. The antigen was prepared by reacting androsterone with succinic anhydride forming androsterone 3alpha succinate and then reducing the 17 ketone to 3alpha diol with sodium borohydride. This was then conjugated with bovine thyroglobulin using the mixed anhydride reaction. Antibody generated in rabbits had high affinity for 3alpha diol and dihydrotestosterone and a lower order of cross reaction with testosterone and 3beta diol. Plasma with 3H indicator is extracted with solvent and purified on a paper chromatogram. Separation of bound from free steroid is affected by ammonium sulfate precipitation. Studies indicate good precision and accuracy. Nonspecific blank values are 8 + or - 8 (SD) pg per sample and sensitivity is about 20 pg. Male values are 13.7 + or - 4 (SD) ng and female values are only 2.0 + or - 0.6 ng per 100 ml with a significant sex difference. Male and female prepubertal values are very low, <2 ng per 100 ml. In a few pathological states, 3alpha diol levels generally paralleled testosterone values.

Alterations in Circulating Estradiol-17?? in Male Patients with Graves's Disease

Article

Feb 1972

Serum concentrations of estradiol-17β (E2), gonadotropins and long acting thyroid stimulator were studied in 10 consecutive male patients with active Graves's disease. Serum E2 was elevated in all patients before therapy. In two men with gynecomastia the concentrations were as high as those observed in normal women. The per cent dialyzable E2 was significantly reduced in hyperthyroid males as compared to normal males and was similar to that seen in eugonadal women; but the absolute concentration of unbound E2, evaluated in one prepubertal and five adult patients without gynecomastia, was elevated in four of the five adults. The mean serum concentrations of luteinizing and follicle-stimulating hormones were also higher in the hyperthyroid men than in normal men. Serum E2 fell gradually and consistently during effective treatment of hyperthyroidism with propylthiouracil. Neither the occurrence of gynecomastia nor the serum concentration of E2 correlated with serum concentration of long acting thyro...

Calculation of free and bound fractions of testosterone and estradiol-17?? to human plasma proteins at body temperature

Abstract

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