[Show abstract][Hide abstract] ABSTRACT: Objective:
To investigate whether pegvisomant treatment in acromegaly induces gradual elevations in endogenous serum growth hormone (GH) levels and whether serum pegvisomant levels predict the therapeutic outcome.
Patients and methods:
Seventeen patients (6 women), mean age 46·3 years (range: 23·2-76·2), were studied. For each patient, four hospital visits were identified including 'active disease' (no treatment) and last follow-up. At each visit, 12 blood samples were drawn during 3 h including an oral glucose tolerance test (OGTT). Eight patients received a somatostatin analogue in addition to pegvisomant on the last visit.
Median (range) pegvisomant doses (mg/day) were 10 (10-10), 15 (10-15) and 15 (10-15) at visits 2, 3 and 4, respectively, and the mean duration of pegvisomant treatment was 17·5 ± 3·2 (SEM) months. Serum IGF-I changed significantly during the treatment period with the highest level at baseline and lowest levels at visits 3 and 4. GH levels increased in a dose-dependent manner during pegvisomant treatment and decreased at visit 4. Changes in IGF-I levels correlated negatively with changes in serum pegvisomant levels between visits. Serum pegvisomant at each visit correlated with baseline growth hormone levels, whereas no associations between serum pegvisomant and either dose, gender, age or body weight were found.
(1) Serum GH levels increased initially, but remained stable during prolonged pegvisomant treatment in patients with acromegaly, (2) serum pegvisomant levels predicted the reduction in serum IGF-I during treatment and (3) the interindividual variation in serum pegvisomant levels seems not predicted by either age, gender or body composition.
Full-text · Article · May 2013 · Clinical Endocrinology
[Show abstract][Hide abstract] ABSTRACT: Cotreatment of acromegaly with pegvisomant and a somatostatin analog (SA) has proven feasible. Previous studies in the field have focused on patients with an insufficient response to SA monotherapy in whom pegvisomant was added without changing the SA dose.
The objective of the study was to study whether patients sufficiently controlled on SA monotherapy can be transferred to combination therapy with low-dose pegvisomant and a reduced SA dose.
Eighteen acromegalic patients well controlled on SA monotherapy, mean ± se aged 54 ± 3 yr, were randomized in a parallel study over 24 wk to unchanged SA monotherapy or cotreatment with pegvisomant (15-30 mg twice a week) and SA (half the usual dosage).
This was an investigator-initiated study in a single tertiary referral center.
Glucose tolerance, substrate metabolism, insulin sensitivity, body composition, and quality of life were measured.
Median pegvisomant dose was 52.5 mg/wk (range 30-60). IGF-I (micrograms per liter) was comparable both at baseline (P = 0.88) and after 24 wk of treatment (P = 0.48). The change in IGF-I between baseline and wk 24 also did not differ between groups (P = 0.15). Apart from increased peak insulin levels during the oral glucose tolerance test in the cotreatment group, no substantial differences between the two groups were detected. Moderately elevated liver enzymes were found in 17% of the patients on pegvisomant therapy.
Acromegalic patients well controlled on SA monotherapy can maintain safe IGF-I levels during 24 wk of cotreatment with low-dose pegvisomant and a 50% reduced SA dose. This treatment modality, however, does not seem to provide significant benefits for the patients.
No preview · Article · Jun 2011 · The Journal of Clinical Endocrinology and Metabolism
[Show abstract][Hide abstract] ABSTRACT: High-dose recombinant human growth hormone (rhGH) (2-6 mg/day) regimes may facilitate T-cell restoration in patients infected with human immunodeficiency virus (HIV) on highly active antiretroviral therapy (HAART). However, high-dose rhGH regimens increase insulin-like growth factor-I (IGF-I) to supra-physiological levels associated with severe side effects. The present study investigated whether lower doses of rhGH may improve T-cell restoration in patients infected with HIV following an expedient response of total and bioactive (i.e., free) IGF-I. A previous 16-week pilot-study included six HIV-infected patients on stable HAART to receive rhGH 0.7 mg/day, which increased total (+117%, P < 0.01) and free (+155%, P < 0.01) IGF-I levels. The study was extended to examine whether continuous use of low-dose rhGH (0.7 mg/day until week 60; 0.4 mg/day from week 60 to week 140) would maintain expedient IGF-I levels and improve CD4 T-cell response. Total and free IGF-I increased at week 36 (+97%, P < 0.01 and +125%, P < 0.01, respectively) and week 60 (+77%, P = 0.01 and +125%, P < 0.01) compared to baseline levels (161 +/- 15 and 0.75 +/- 0.11 microg/L). CD4 T-cell number increased at week 36 (+15%, P < 0.05) and week 60 (+31%, P = 0.01) compared to baseline levels (456 +/- 55 cells/microL). Following rhGH dose reduction, total IGF-I and CD4 T-cell number remained increased at week 88 (+44%, P = 0.01 and +33%, P < 0.01) and week 140 (+46%, P = 0.07 and +36%, P = 0.02) compared to baseline levels. These data support the notion that low-dose rhGH regimens may increase expediently total and bioactive IGF-I and improve T-cell restoration in patients infected with HIV on HAART.
No preview · Article · Feb 2010 · Journal of Medical Virology
[Show abstract][Hide abstract] ABSTRACT: The influence of growth hormone on bone formation, mechanical strength, and composition has been investigated in femur middiaphyseal cortical bone from 2-year-old male rats. The rats were given biosynthetic human growth hormone (bhGH) at 2.7 mg/kg/day in two daily injections for 20, 40, or 80 days, and all animals were killed 80 days after the start of bhGH administration. Control animals were given saline. All animals were labeled with tetracycline on days 41 and 69. Only in the bhGH-80-day group was subperiosteal tetracycline double labeling seen all around the femur diaphysis, and this pattern was found in all animals of the group. Double labeling subperiosteally at the posteromedial aspect was found in all animals of the experiment, but compared with the control group, a 400% and an 800% increase in mineral apposition rate was seen in the bhGH-40-day and bhGH-80-day groups, respectively. Light microscopy and polarization microscopy showed that this newly deposited bone was organized in the same concentric lammellae and had the same direction of the collagen fibers when compared with the surrounding bone formed before the start of bhGH injections. The cortical bone cross-sectional area was increased in the bhGH-40-day and bhGH-80-day groups. At the endosteum, scattered labeling was found in animals from all groups, and no differences in medullary cross-sectional areas were seen. The mechanical analysis revealed an increased mechanical strength of the whole diaphyseal bone after bhGH administration. When the data were corrected for dimensions of the diaphyseal bone, no differences in intrinsic mechanical properties of the bone tissue were found. No differences in apparent density of dry defatted bone, ash, and collagen were seen, whereas apparent density of dry defatted bone minus ash was decreased in all groups given bhGH. Correspondingly, a slight increase in ash concentrations of the bhGH-injected animals was seen. bhGH administration also increased the body weight, muscle mass, and total serum IGF-I and thyroxine concentrations.
No preview · Article · Jul 2009 · Journal of Bone and Mineral Research
[Show abstract][Hide abstract] ABSTRACT: Cardiac function was studied by echocardiography in 12 patients with active acromegaly and in 12 age- and sex-matched healthy control subjects. None of the patients had cardiovascular diseases or other endocrine diseases than acromegaly. The patients had a mean age of 39±5 years and were short-term acromegalic with a mean duration of disease of 6±3 years. Mean left ventricular mass was 163±43 g/m2 in the acromegalic group versus 120±24 g/m2 in the control group. Preload (the diastolic diameter of the left ventricle) was within normal limits, while afterload (end-systolic meridional wall stress) was significantly decreased in the acromegalic group. Myocardial contractility assessed as fractional shortening of the left ventricle was 39.9±3.6% in the acromegalic group versus 32.9±5.1% in the control group, and cardiac output was increased by 52% in the acromegalic group because of increased heart rate and stroke volume. We suggest that augmented peripheral blood flow is responsible for the condition of cardiac hyperkinesia in short-term acromegaly and involved in the development of hypertension, which is a frequent complication of long-term acromegaly.
No preview · Article · Apr 2009 · Journal of Internal Medicine
[Show abstract][Hide abstract] ABSTRACT: Alterations in circulating iodothyronines were studied in 15 juvenile type diabetic patients during the development of metabolic derangement after withdrawal of insulin. By means of measurements of circulating C peptide, one group of patients with and one without residual β-cell function had been selected. In both groups there was a gradual decrease in serum T3 during the 12-hour period studied after withdrawal of insulin, while an increase in serum rT3 was observed after 4–6 hours. The alterations in serum T3 and the metabolic derangement were significantly more pronounced in patients without than with residual β-cell function.
No preview · Article · Apr 2009 · Journal of Internal Medicine
[Show abstract][Hide abstract] ABSTRACT: Growth hormone (GH) reduces the catabolic side effects of steroid treatment via effects on the amino-nitrogen metabolism. Ipamorelin is a synthetic peptide with GH releasing properties. We wished to study the metabolic effects of Ipamorelin and GH on selected hepatic measures of alpha-amino-nitrogen conversion during steroid-induced catabolism.
Five groups of rats were included: (1) free-fed controls (2) pair-fed controls (3) prednisolone (delcortol, 4 mg x kg(-1) x day(-1)) (4) prednisolone and GH (1 mg x kg(-1) x day(-1)) (5) prednisolone and Ipamorelin (0.5 mg x kg(-1) x day(-1)). After seven days the hepatic capacity of urea-N synthesis (CUNS) was determined in parallel with measurements of liver mRNA levels of urea cycle enzymes, whole-body N-balance, and N-contents of various organs.
Compared to pair-fed controls, prednisolone increased CUNS (p<0.01) as well as the expression of urea cycle genes (p<0.01), and decreased N-balance (p<0.01) as well as organ N-contents (p<0.05). Compared to prednisolone treated animals, co-administration of GH reduced CUNS by 33% (p<0.01), normalized urea cycle gene expression, improved N-balance 2.5-fold, and normalized or improved organ N-contents. In prednisolone treated rats Ipamorelin reduced CUNS by 20% (p<0.05), decreased the expression of urea cycle enzymes, neutralised N-balance, and normalized or improved organ N-contents.
Accelerated nitrogen wasting in the liver and other organs caused by prednisolone treatment was counteracted by treatment with either GH or its secretagogue Ipamorelin, though at the doses given less efficiently by the latter. This functional study of animals confirms that the GH secretagogue exerts GH related metabolic effects and may be useful in the treatment of steroid-induced catabolism.
Full-text · Article · Mar 2009 · Growth hormone & IGF research: official journal of the Growth Hormone Research Society and the International IGF Research Society
[Show abstract][Hide abstract] ABSTRACT: In 27 patients with multiple sclerosis (MS), and in 10 control subjects of comparable age, percent ideal body weight and sex ratio, the cerebrospinal fluid (CSF) content of somatostatin was measured by radioimmunoassay.
The results showed that the group of patients in relapse (n = 16) had significantly lower somatostatin content in CSF (95 ± 4.1 (SEM) pg/ml) than both the control group (142 ± 8.4 pg/ml) and the group of MS patients (n =11), who had been in a clinical stable phase for more than 6 months (131 ± 3.2 pg/ml). Duration of the disease and degree of neurological impairment were apparently without relation to the reduction of somatostatin content in the CSF. There was no relationship between CSF content of somatostatin and the content of total protein or IgG, neither of which showed any relationship to the activity of the disease.
No preview · Article · Jan 2009 · Acta Neurologica Scandinavica
[Show abstract][Hide abstract] ABSTRACT: Epidemiological studies imply an association between circulating IGF1 and breast cancer, whereas the role of IGF2, which also acts on the IGF1 receptor, is less settled. This study investigates the association between IGF2 and breast cancer in patients with localized disease.
The participants were women with well-characterized, early stage, localized breast cancer (n=43) and matched healthy women (n=38), from whom fasting serum levels of IGF-related peptides were measured.
In patients, mean free IGF2 was increased (+57%, P<0.001), in spite of reduced total IGF2 levels (-12%, P=0.003) when compared with controls. Similar changes were seen in free IGF1 (+28%, P=0.004) and total IGF1 (-16% P=NS). Pro-IGF2 and IGF-binding protein 1 (IGFBP1) were unchanged. IGFBP2 was reduced by 22% in the patients (P=0.004). The patients showed reduced IGFBP3 protease activity and accordingly increased levels of intact IGFBP3, whereas total IGFBP3 was unchanged.
Women with localized, early-stage breast cancer show elevated circulating free IGF1 and IGF2, reduced total IGF2 and alterations in IGFBPs. The changes observed despite minimal cancer disease suggest a role for the circulating IGF system in the progression of breast cancer in women.
Preview · Article · Sep 2008 · European Journal of Endocrinology
[Show abstract][Hide abstract] ABSTRACT: Fasting is characterized by increased whole body lipolysis and lipid oxidation, decreased glucose oxidation and insulin resistance. To identify the regional sources and underlying mechanisms, we studied 10 healthy male volunteers post-absorptively and after 72 h of fasting.
Each study comprised a 3-h basal period and a 3-h hyperinsulinaemic euglycaemic clamp and we used a combination of leg and forearm arteriovenous techniques, upper and lower body microdialysis and glucose and palmitate tracers.
In the basal state, plasma levels, fluxes and oxidation rates of free fatty acids all roughly doubled after fasting. Palmitate fluxes across the forearm and leg also increased by two to threefold and interstitial leg muscle glycerol concentrations doubled. Subcutaneous femoral glycerol concentrations and blood flows were unaltered, but abdominal subcutaneous blood flow increased by 50% in the presence of unchanged glycerol concentrations, indicating stimulated abdominal lipolysis. During the clamp, we observed whole body insulin resistance and glucose uptake across the leg and forearm decreased by 60%.
Our data show that fasting induces insulin resistance in upper and lower body muscles and suggest that increased lipolysis, is primarily due to the activation of lipolysis in muscle-associated fat (in the leg) and in upper body subcutaneous fat, whereas peripheral subcutaneous fat is spared.
Full-text · Article · Dec 2007 · Acta Physiologica
[Show abstract][Hide abstract] ABSTRACT: Growth hormone (GH) and the GH receptor blocker, pegvisomant are usually circulating in high concentration in pegvisomant treated acromegalic patients. This and the close similarity between the peptides make determination of either difficult. In the present methodological study, endogenous GH in serum is initially isolated and determined in a slightly modified commercial immunometric assay, whereafter the now GH free medium allows measurement of pegvisomant. Inter-individual steady state levels of serum pegvisomant vary remarkably in both acromegalic patients and healthy controls, while the intra-individual variations are negligible.
No preview · Article · Nov 2007 · Growth Hormone & IGF Research
[Show abstract][Hide abstract] ABSTRACT: Pegvisomant is a specific GH receptor antagonist that is able to normalize serum IGF-I concentrations in most patients with acromegaly. The impact of pegvisomant on insulin sensitivity and substrate metabolism is less well described.
We assessed basal and insulin-stimulated (euglycemic clamp) substrate metabolism in seven patients with active acromegaly before and after 4-wk pegvisomant treatment (15 mg/d) in an open design.
After pegvisomant, IGF-I decreased, whereas GH increased (IGF-I, 621 +/- 82 vs. 247 +/- 33 microg/liter, P = 0.02; GH, 5.3 +/- 1.5 vs. 10.8 +/- 3.3 microg/liter, P = 0.02). Basal serum insulin and plasma glucose levels decreased after treatment (insulin, 54 +/- 5.9 vs. 42 +/- 5.3 pmol/liter, P = 0.001; glucose, 5.7 +/- 0.1 vs. 5.3 +/- 0.0 mmol/liter, not significant), whereas palmitate kinetics were unaltered. During the clamp, the glucose infusion rate increased after pegvisomant (3.1 +/- 0.5 vs. 4.4 +/- 0.6 mg/kg.min, P = 0.02), whereas the suppression of endogenous glucose production tended to increase (0.7 +/- 0.0 vs. 0.5 +/- 0.1 mg/kg.min, not significant). Total resting energy expenditure decreased after pegvisomant treatment (1703 +/- 109 vs. 1563 +/- 101 kcal/24 h, P = 0.03), but the rate of lipid oxidation did not change significantly.
1) Pegvisomant treatment for 4 wk improves peripheral and hepatic insulin sensitivity in acromegaly. 2) This is associated with a decrease in resting energy expenditure, whereas free fatty acid metabolism is unaltered. 3) The data support the important direct effects of GH on glucose metabolism and add additional benefits to pegvisomant treatment for acromegaly.
Full-text · Article · Jun 2007 · Journal of Clinical Endocrinology & Metabolism
[Show abstract][Hide abstract] ABSTRACT: We tested the effect of co-treatment of acromegaly with a somatostatin analogue (SA) and a growth hormone receptor antagonist (GHA). Eleven patients underwent: 1) conventional treatment with SA, 2) discontinued treatment, 3) 6 weeks treatment with GHA (10 mg), 4) 6 weeks treatment with GHA (15 mg), 5) 3 months combined SA and GHA. Circulating IGF-I was lowered by GHA and more so with combined treatment. Treatment with GHA increased endogenous GH levels, which was partly reversed by combined treatment. Plasma glucose levels were highest during SA treatment and lowest with GHA. Co-treatment of acromegaly with SA and GHA is a promising concept.
No preview · Article · Apr 2007 · Ugeskrift for laeger
[Show abstract][Hide abstract] ABSTRACT: Low-dose growth hormone (GH) administration has been suggested as a treatment for HIV-lipodystrophy.
Postglucose GH-secretion, kinetics of insulin-like growth factors (IGFs), insulin, and glucose metabolism were examined in six male HIV-infected lipodystrophic patients (two normal-weight patients with normal glucose-tolerance (NGT), two normal-weight with impaired glucose-tolerance (IGT), and two obese patients with diabetes (DM)) during a 16 weeks open-labelled pilot-study of low-dose GH, 0.7 mg/day.
DM, compared to NGT and IGT, displayed an impaired rebound of GH during a 5h oral glucose-tolerance test. Near lower normal limits in all patients before GH-therapy, total and free IGF-I increased between 87 and 152% during the GH-therapy (P<0.001), approaching upper normal limits in all patients with the highest incremental percentages shown in DM. A slight and temporary reduction in insulin sensitivity was caused by a reduction in non-oxidative glucose metabolism (n=5). GH-administration reduced hepatic extraction of insulin alleviating the demand for insulin secretion (n=5). No adverse effects of GH were detected.
As judged from effects on circulating IGF-I, glucose metabolism, and insulin kinetics, 0.7 mg/day of GH may be expedient for treatment of HIV-infected males with lipodystrophy. Whether the patients' glucose metabolic status matters for the IGF-response to low-dose GH-therapy awaits further investigation.
No preview · Article · Jul 2006 · The Journal of infection
[Show abstract][Hide abstract] ABSTRACT: Intravenous infusion of basic amino acids is used experimentally and pharmacologically to prevent renal proximal tubular uptake of filtered proteins. Intravenously injected L-lysine is rapidly cleared from plasma and the effect on tubular protein reabsorption is transient. To obtain a more sustained effect, we developed a model of oral L-lysine administration and characterized this model by analyzing urinary protein excretion and proximal tubule uptake of filtered proteins. Rats placed in metabolic cages were treated with 20 mmol/kg/6 h of L-lysine, glycine, or water. Urines were analyzed for proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, immunoblotting, and radioimmunoassay. Proximal tubule uptake of proteins and expression of apical membrane receptors were investigated by immunocytochemistry. In vitro uptake and receptor expression were studied using a yolk sac cell line. L-lysine administration produced increased urinary excretion of a large number of proteins while the effect on tubular accumulation of selected proteins was variable. L-lysine treatment induced changes in the localization of two receptors responsible for tubular endocytosis of filtered proteins. In conclusion, oral L-lysine treatment induced proteinuria, in particular albuminuria, as efficiently as previous reports on intravenous infusion. The effect on tubular protein accumulation was variable suggesting differential effects on tubular reabsorption and degradation of filtered proteins. Changes in tubular protein handling were accompanied by changes in the localization of the endocytic receptors, megalin, and cubilin. In vitro experiments supported the in vivo observations. The findings suggest that L-lysine may affect receptor trafficking in addition to possible effects on the direct binding of ligands to the receptors.
Preview · Article · May 2006 · Kidney International
[Show abstract][Hide abstract] ABSTRACT: During pregnancy, placental growth hormone (PGH) is secreted into the maternal circulation, replacing pituitary GH. It is controversial whether PGH levels decline during vaginal birth. After placental expulsion, PGH is eliminated from the maternal blood. GH binding protein (GHBP) and body mass index (BMI) influence GH kinetics, but their impact on PGH kinetics is unknown. The present study was undertaken to define the kinetics of PGH during vaginal delivery and Caesarian section and to relate these kinetics to GHBP and BMI.
A short term, prospective cohort study.
Twelve women had repeated blood samples drawn during vaginal delivery. From 26 women undergoing planned Caesarian delivery (CS) repeated blood samples were withdrawn before, during and after the CS, allowing PGH half-life determination.
During vaginal delivery, median PGH values did not change before expulsion of the placenta, although individual fluctuations were seen. Clearance of PGH from the maternal circulation was best described by a two-compartment model. The initial half-life of serum PGH was (mean +/- s.d.) 5.8 +/- 2.4 min, and the late half-life was (median) 87.0 min (range: 25.1-679.6 min). The late half-life was correlated to the pre-gestational BMI (r = 0.39, P = 0.047), but not to the serum GHBP concentration.
Serum PGH did not decrease significantly during vaginal delivery. Elimination of PGH fitted a two-compartment model, with an estimated initial half-life of 5.8 min. The late phase serum half-life of PGH was related to BMI, suggesting a role for maternal fat mass in PGH metabolism.
No preview · Article · Apr 2006 · European Journal of Endocrinology
[Show abstract][Hide abstract] ABSTRACT: The present study was designed as a randomized, double-blind placebo (Plc)-controlled study to determine the effect of 2 wk of growth hormone administration (GH-adm.) on energy expenditure (EE) and substrate oxidation in healthy humans. Sixteen young healthy men were divided into two groups. The study consisted of two 24-h measurements (indirect calorimetry), separated by 2 wk of either Plc or GH injections (6 IU/day). At baseline, no significant differences were observed between the two groups in any of the measured anthropometric, hormonal, or metabolic parameters, neither did the parameters change over time in the Plc group. GH-adm. resulted in a 4.4% increase in 24-h EE (P < 0.05) and an increase in fat oxidation by 29% (P < 0.05). However, a decrease in the respiratory quotient was only observed in the postabsorptive phase after an overnight fast (0.84 +/- 0.1 to 0.79 +/- 0.1, P < 0.05). Furthermore, lean body mass (LBM) was increased by GH-adm. only [62.8 +/- 2.5 kg (baseline) vs. 64.7 +/- 2.4 kg (after), P < 0.001]. In conclusion, GH-adm. increases 24-h EE, which may be partly explained by increased LBM. Furthermore, GH-adm. stimulates fat combustion, especially in the postabsorptive state.
Full-text · Article · Dec 2005 · AJP Endocrinology and Metabolism