OBJECTIVEThis study evaluated the effects of testosterone replacement therapy (TRT) on insulin resistance, cardiovascular risk factors, and symptoms in hypogonadal men with type 2 diabetes and/or metabolic syndrome (MetS).RESEARCH DESIGN AND METHODSThe efficacy, safety, and tolerability of a novel transdermal 2% testosterone gel was evaluated over 12 months in 220 hypogonadal men with type 2 diabetes and/or MetS in a multicenter, prospective, randomized, double-blind, placebo-controlled study. The primary outcome was mean change from baseline in homeostasis model assessment of insulin resistance (HOMA-IR). Secondary outcomes were measures of body composition, glycemic control, lipids, and sexual function. Efficacy results focused primarily on months 0−6 (phase 1; no changes in medication allowed). Medication changes were allowed in phase 2 (months 6−12).RESULTSTRT reduced HOMA-IR in the overall population by 15.2% at 6 months (P = 0.018) and 16.4% at 12 months (P = 0.006). In type 2 diabetic patients, glycemic control was significantly better in the TRT group than the placebo group at month 9 (HbA1c: treatment difference, −0.446%; P = 0.035). Improvements in total and LDL cholesterol, lipoprotein a (Lpa), body composition, libido, and sexual function occurred in selected patient groups. There were no significant differences between groups in the frequencies of adverse events (AEs) or serious AEs. The majority of AEs (>95%) were mild or moderate.CONCLUSIONSOver a 6-month period, transdermal TRT was associated with beneficial effects on insulin resistance, total and LDL-cholesterol, Lpa, and sexual health in hypogonadal men with type 2 diabetes and/or MetS.
Men with coronary artery disease have significantly lower levels of androgens than normal controls, challenging the preconception that physiologically high levels of androgens in men account for their increased relative risk for coronary artery disease.
SummaryIn this study, 126 patients (90 males, average age 56 years, range 39-80) were randomised to Wu Chian-Ch'uan style Tai Chi (38), aerobic exercise (41) or a non-exercise support group (47) following acute myocardial infarction. Patients attended twice weekly for three weeks then weekly for a further five weeks. Heart rate and blood pressure were recorded before and after each session. Over the 11 sessions of exercise there was a negative trend in diastolic blood pressure only in the Tai Chi group (Rs=0.79, p<0.01). Significant trends in systolic blood pressure occurred in both exercise groups (Rs=0.64 and 0.63, both p<0.05). Only four (8%) patients completed the support group eight-week programme which was less than the number completing Tai Chi (82%; p <0.001) and aerobic exercise groups (73%; p<0.001).
It is well recognised that oestrogens possess vasodilatory properties, and similar responses to testosterone have been demonstrated. However, vasomotor effects of other steroid hormones have not been well described. Direct comparisons of the relative vasoactivity of different steroid hormones in different vascular beds in male and female genders have not been made. Coronary and pulmonary arteries from adult Wistar rats were mounted in a wire myograph, loaded to 100 and 17 mmHg respectively, maximally pre-contracted with 1 x 10(-4) M prostaglandin-F-2-alpha, and dose response curves to 1 x 10(-6) to 1 x 10(-3) or 3 x 10(-3) M of 17 beta-oestradiol, testosterone, progesterone, and cortisol dissolved in water were constructed. Addition of each steroid hormone caused acute, dose dependent dilatation in coronary and pulmonary vessels. In coronary arteries the order of activity was testosterone > progesterone > 17 beta-oestradiol > cortisol, p < 0.001. In pulmonary arteries, the order of activity was progesterone > testosterone > cortisol > 17 beta-oestradiol, p < 0.001. Pulmonary arteries from male animals were more sensitive to the effects of testosterone than those from female animals, p = 0.003, whereas coronary arteries from female animals were more sensitive to the effects of 17 beta-oestradiol than those from male animals, p < 0.001. We have demonstrated significant differences in the in vitro vasomotor effects of different steroid hormones in two distinct vascular beds. Gender differences in vasomotor responses to steroid hormones may play a role in the aetiology of vasospastic diseases.
Objective: In the absence of widely available measures of determining free and/or bioavailable testosterone (BioT) physicians may use formulae such as the free androgen index (FAI) to estimate free testosterone. We compared the efficacy of calculated markers of androgen status in predicting serum BioT and hypogonadism. Design: Total testosterone (TT), sex hormone binding globulin (SHBG) and BioT were determined in a large cohort of men. Comparison of calculated androgen levels was performed following endocrine assessment. Methods: TT and SHBG were determined by ELISA, and BioT was determined by ammonium sulphate precipitation. From these data we calculated FAI and free testosterone using two other published formulae -FTnw (free testosterone as calculated by the method of Nanjeee and Wheeler) and FTv (free testosterone as calculated by the method of Vermeulen). A novel formula was derived to calculate BioT from given levels of TT and SHBG (BTcalculated). The ability of the methods (FAI, FTnw, FTv, BTcalc) to predict BioT were compared using regression analysis. The ability of these markers of androgen status to predict biochemical hypogonadism was compared using area under receiver operator curve (auROC). Results: The equation derived from our data was the best predictor of BioT (R 2 ¼ 0.73, P , 0.0001) although TT was also a good marker (R 2 ¼ 0.68, P ¼ 0.0001). In the determination of hypogonadism, of all currently available formulae none were better that the TT (
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