Effects of long-term simvastatin treatment on testicular and adrenal steroidogenesis in hypercholesterolemic patients.

Simvastatin is an inhibitor of 3-hydroxy-3-methyl glutaryl coenzyme A (HMG-CoA) reductase, the key enzyme in the synthesis of cholesterol, recently introduced in the therapy of hypercholesterolemic patients. Cholesterol is the precursor of the biosynthesis of steroid hormones; thus, a reduction of the availability of cholesterol in the adrenal and testicular cells may reduce the synthesis of corticosteroids and androgens. To establish whether chronic therapy with simvastatin interferes with the integrity of the hypothalamic-pituitary-adrenal axis and with the adrenal and testicular reserve, we administered simvastatin orally in a single-day 10 mg dose for 6 months in 8 mildly hypercholesterolemic male patients. At weeks 0, 6 and 24 of treatment we evaluated the lipids, the activity of the hypothalamic-pituitary-adrenal axis by means of the Corticotropin-Releasing Hormone (CRH) test, the adrenal reserve by means of the Corticotropin rapid test and, finally, the testicular reserve by means of the Human Chorionic Gonadotropin (HCG) test. Total cholesterol and LDL-cholesterol were significantly reduced by Simvastatin, while the HDL-cholesterol and triglycerides did not change significantly. The hormonal responses to CRH, ACTH and HCG tests at weeks 6 and 24 of treatment were comparable to those obtained in basal conditions. We conclude that Simvastatin, while effective in reducing total and LDL-cholesterol in hypercholesterolemic male patients, did not interfere with hypothalamic-pituitary-adrenal axis activity or with basal and stimulated adrenal and testicular steroidogenesis.