Effects of orchidectomy in selective biochemical analytes in Beagle dogs.
ABSTRACT The objective of this study was to evaluate the possible effects of orchidectomy and associate hormonal changes on circulating concentrations of acute-phase proteins (APPs) (CRP--C-reactive protein; Hp--haptoglobin; Cp--ceruloplasmin), adiponectin and IGF-1 in dogs. For this, a total of five adult Beagle dogs were subjected to orchidectomy. Blood samples were taken before neutering, during six consecutive days and on weeks 2, 4, 8 and 12 after surgery. Appropriate diet regime was maintained to keep stable body weight of the dogs. Concentrations of APPs significantly increased on days 2-3 for CRP and 2-7 for Hp and Cp. On days 3-4 after neutering, adiponectin levels were significantly lower than before surgery (p<0.05 and <0.01, respectively). After this initial change, adiponectin did not show any significant alteration during the 3 months. Serum IGF-1 concentrations were significantly decreased at days 2-5 after neutering. In addition, on weeks 8 and 12 serum IGF-1 levels were significantly lower (p<0.001 and <0.01 respectively) in comparison with those before surgery. In conclusion, orchidectomy induced a short-term inflammatory process that was associated with the increase in serum levels of APPs and decrease in IGF-1 and adiponectin levels. However, orchidectomy did not result in long-term changes of circulating concentrations of APPs or adiponectin. Although a decrease in IGF-1 levels was recorded 2 months after surgery, possibly as a consequence of associated decrease in androgen levels or food restriction.
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ABSTRACT: Because male sex is an independent risk factor for the severity of atherosclerosis, it is possible that androgens may be proatherogenic. There is evidence that sex hormones, particularly estrogens, regulate (or modulate) inflammation, a process integral to atherogenesis. Because levels of serum inflammatory markers predict cardiovascular outcomes, we prospectively assessed the effects of androgen therapy on these markers in older men. Levels of high-sensitivity C-reactive protein (CRP), soluble intracellular adhesion molecule-1 (sICAM-1), and soluble vascular cell adhesion molecule-1 (sVCAM-1) were measured from sera collected at baseline and at the end of 2 randomized double-blind placebo-controlled trials evaluating the effects of 3 months of androgen treatment with either dihydrotestosterone (DHT) or recombinant human chorionic gonadotropin (rhCG) in healthy men aged >60 years with partial androgen deficiency (serum testosterone levels <15 nmol/L). For the DHT study (70 mg transdermally daily), 33 men completed 3 months of treatment (16 men were treated with DHT, and there were 17 controls). For the rhCG (250 microg twice weekly) study, 20 men were treated with rhCG, and there were 20 controls. In both studies, groups were well matched for age and vascular risk factors. Androgen levels (DHT and testosterone) were consistently maintained at eugonadal levels throughout the trials, with estradiol markedly increased by rhCG but not DHT. Baseline CRP levels were 0.74 to 1.49 mg/L, sVCAM-1 levels were 847 to 950 ng/mL, and sICAM-1 levels were 256 to 292 ng/mL in all groups. Neither DHT nor rhCG resulted in significant changes in CRP, sVCAM-1, or sICAM-1 compared with placebo (P>0.3 in both studies). Exogenous androgen therapy with or without increased estradiol levels does not alter serum inflammatory markers in older men; this finding is in contrast to the effects of estrogens on inflammatory markers that have been found in postmenopausal women. These data provide a measure of reassurance concerning potential adverse cardiovascular effects of androgen therapy in older men.Arteriosclerosis Thrombosis and Vascular Biology 08/2002; 22(7):1136-41. · 6.34 Impact Factor
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ABSTRACT: Androgens and oestrogens have opposing effects on some adipocyte functions. Thus, the androgen to oestrogen balance may be as important as the individual hormones in determining the biological interaction between endogenous sex hormones and adipocyte-derived factors such as adiponectin and leptin. We tested this hypothesis by evaluating the sex-specific, cross-sectional association of sex hormones and androgen to oestrogen ratios with serum adiponectin and leptin in older men and postmenopausal women. Cross-sectional. A total of 1510 community dwelling men and postmenopausal women aged 50-92 years. Serum leptin, adiponectin and sex hormone levels. Adiponectin and leptin levels were higher in women than men (P < 0.001). In both sexes, adiponectin concentrations were lower, and leptin levels higher, with increasing BMI and waist girth (all P < 0.001). Although the ratio of total testosterone to total oestradiol was significantly associated with both adipocytokines in both sexes, the strongest and most consistent hormone-adipocytokine associations were observed when the androgen to oestrogen ratio was expressed as total testosterone to bioavailable oestradiol. In linear regressions, the testosterone to bioavailable oestradiol ratio was positively related to adiponectin and inversely related to leptin, with nearly identical standardized beta-coefficients for men and women (all P < 0.001). The strength of the hormone ratio-adipocytokine associations was reduced, but not eliminated, after adjustment for age, adiposity and cardiovascular disease risk factors, including insulin resistance. The striking similarity of the hormone ratio-adipocytokine associations for men and women, despite wide differences in sex hormone and adipocytokine levels, suggests these results reflect underlying physiological mechanisms common to both sexes.Clinical Endocrinology 11/2006; 65(4):506-13. · 3.40 Impact Factor
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ABSTRACT: Adiponectin is an adipocyte-specific secretory protein which exhibits antiatherogenic, anti-inflammatory and antidiabetic properties. We hypothesized that testosterone plays an important role in the regulation of its secretion in humans, as adiponectin concentrations are higher in women than in men and as testosterone administration is accompanied by a reduction in serum adiponectin in animals and by reduced protein secretion in cultured adipocytes. This study aimed to evaluate adiponectin levels in hypogonadal men prior to and during testosterone replacement therapy. In a retrospective study, adiponectin, total and free testosterone, oestradiol, SHBG, total cholesterol and triglyceride levels were evaluated in 31 hypogonadal men [HM; age, mean +/- SEM: 36.5 +/- 2.4 years; body mass index (BMI) 24.6 +/- 0.8 kg/m2] and 29 weight-matched eugonadal men (EM; age 30.8 +/- 1.5 years; BMI 23.4 +/- 0.6 kg/m2). In 13 HM (age 33.9 +/- 3.2 years; BMI 24.2 +/- 0.9 kg/m2) the same parameters were also evaluated after 6 months of testosterone replacement therapy. Correlation analysis between adiponectin and hormonal, biochemical and anthropometric parameters was performed in all subjects. Testosterone, free testosterone and oestradiol concentrations were significantly lower in HM than in EM (4.4 +/- 0.4 nmol/l, 78.4 +/- 10.9 pmol/l and 36.1 +/- 3.0 pmol/l, respectively, in HM vs. 21.9 +/- 0.7 nmol/l, 507.9 +/- 13.8 pmol/l and 65.2 +/- 1.8 pmol/l, respectively, in EM, P < 0.0001), while SHBG levels in HM were higher than in EM (54.4 +/- 7.5 vs. 30.9 +/- 2.2 nmol/l, P < 0.005). Serum adiponectin levels in HM were significantly higher than in EM (9.53 +/- 0.73 vs. 6.80 +/- 0.55 microg/ml, P < 0.01). Calculation of the Pearson coefficient showed that adiponectin levels in HM were not correlated with any of the anthropometric and hormonal parameters examined, but showed a significant negative correlation with serum triglycerides (r = -0.38, P < 0.05). Serum adiponectin levels were negatively correlated with body weight (r = -0.41, P < 0.05) in EM but not with other anthropometric, hormonal or biochemical parameters. Six months after initiation of testosterone replacement therapy, which increased testosterone and free testosterone levels to the normal range, adiponectin levels were significantly reduced in HM (6.37 +/- 0.93 vs. 9.26 +/- 1.01 microg/ml, P < 0.01) and similar to those recorded in EM. Compared to eugonadal subjects, hypogonadal men show higher adiponectin levels which are reduced by testosterone replacement therapy. This study indicates that testosterone exerts a regulatory role on adiponectin secretion in humans.Clinical Endocrinology 04/2004; 60(4):500-7. · 3.40 Impact Factor