Testicular function in hypercholesterolemic male patients during prolonged simvastatin treatment

Simvastatin is a very effective hypocholesterolemic drug which, reducing cholesterol biosynthesis, can affect normal steroid hormone production. Testes require a continuous cholesterol supply for testosterone synthesis and this can be derived from low density lipoprotein receptor-mediated uptake or from de novo local synthesis. The aim of the study was to see if prolonged simvastatin treatment compromised endocrine testicular function both in basal conditions and after stimulation by human Chorionic Gonadotropin (hCG) (Profasi 5,000 Ul, i.m. at 8 a.m.). Free testosterone (FT) levels were determined at baseline and after 3, 6 and 12 months of simvastatin treatment (20 mg/day) in eight hypercholesterolemic patients. At the same time we performed a hCG stimulation test to evaluate testicular reserve. A significant reduction of FT, both basal and hCG-stimulated, was observed in the 6th and the 12th month of the study. However, FT levels remained in the normal range and no patient complained of gonadal function related symptoms. No significant change was observed in estradiol response to hCG test. Lastly, there was no variation in LH, FSH, progesterone, 17-OH-progesterone, androstenedione or dehydroepiandrosterone-sulphate levels. Our study concluded that the drug causes a mild decline in FT secretion without any clinical sign of testicular dysfunction.