Endocrine Abstracts (2013) 32 P193 | DOI: 10.1530/endoabs.32.P193

HDL cholesterol subfractions and the effect of testosterone replacement in hypogonadism

Erol Bolu1, Alper Sonmez1, Serkan Tapan2, Abdullah Taslipinar1, Aydogan Aydogdu1, Coskun Meric1, Yalcin Basaran1, Gokhan Uckaya1, Muhittin A Serdar2, Ismail Kurt2 & Omer Azal1

1Department of Endocrinology and Metabolism, Gulhane Military Medical Academy, Ankara, Turkey; 2Department of Clinical Biochemistry, Gulhane Military Medical Academy, Ankara, Turkey.

Metabolic disorders and cardiovascular events are increased in hypogonadism. Serum HDL composition is a better cardiovascular predictor than the HDL counts. However, there is no information about the HDL subfractions in patients with hypogonadism. We designed a prospective study to investigate the HDL subfractions in treatment naïve subjects with hypogonadism and the effects of two different testosterone replacement regimens on the HDL subfractions. Seventy young male patients with congenital hypogonadotropic hypogonadism (CHH) and 70 age and BMI-matched healthy males were enrolled in the present study. The patients were assigned to receive intramuscular injections of testosterone esters 250 mg every 3 weeks and transdermal testosterone applications 50 mg daily. Biochemical investigations including HDL subfractions and insulin resistance were done. Patients with CHH had higher levels of insulin, HOMA-IR, WC, triglyceride, and diastolic blood pressure. Although, the HDL cholesterol concentrations were similar in both groups, hypogonadal patients had lower HDL2 and higher HDL3 levels. The total testosterone levels were independent determinants of the HDL2 subfractions. During the follow-up, a significant increase in the BMI and WC values and a significant decrease in the levels of total cholesterol, HDL cholesterol and HDL3 were observed. No difference was present between the two treatment arms. These results show that low testosterone levels in hypogonadism may be associated with unfavorable HDL subfractions. Nevertheless, neither metabolic disorders nor the unfavorable HDL subfractions were able to improve with testosterone replacement therapy. The implications of these findings for the cardiovascular health should be sought with prospective follow up studies.