Background: Cross sectional studies in type 2 diabetic men have shown the 50% prevalence of hypogonadism. Testosterone deficiency worsens glycaemic control and accelerates the development of cardio-vascular disease. Therefore we investigated the effects of testosterone replacement therapy (TRT) on endothelial function in hypogonadal men with type 2 diabetes.
Patients and methods: Thirty-three hypogonadal patients with type 2 diabetes, aged 35 years or older with testosterone levels below 8 nmol/l, were put on TRT (Nebido 1000 mg i.m). Before and seven months after TRT the parameters of metabolic control (HbA1c, lipids) and body composition using Dual energy X-ray absorptiometry (DXA) were measured. The endothelial function was assessed by measuring the endothelium-dependent flow-mediated vasodilation (FMD) of the brachial artery using a high resolution ultrasound. Patients filled out the AMS questionnaire before and after TRT.
Results: Serum testosterone levels increased from 6.6±1.7 to 8.6±2.1 nmol/l (P=0.000) after 7 months of TRT. FMD increased from 4.2±4.5% to 7.4±4.8%, (P=0.009). An increase in lean body mass from 73.9±9.5 to 74.9±9.5 kg (P=0.045) and a decrease in total body fat mass from 23.2±5.2 to 22.2±5.6 kg (P=0.006) was observed. There were no significant changes in lipid and HbA1c levels. The AMS score improved significantly.
Conclusions: Our trial was the first to examine the influence of TRT on the endothelial function in hypogonadal men with type 2 diabetes. TRT significantly improved endothelial function, body composition and symptoms of late-onset hypogonadism without influencing parameters of metabolic control. The beneficial effects of TRT on the endothelium might be testosterone mediated directly or indirectly via aromatisation to estradiol.
Prague, Czech Republic
24 - 28 Apr 2010
European Society of Endocrinology