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.

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The aim of the present study was to test whether the serotoninergic system may be involved in the well known reduced growth hormone (GH) response to insulin-induced hypoglycaemia (IIH) in obese patients. Ten obese women and 10 normal-weight control women underwent three IIH tests, at 14-day intervals: the first in basal conditions, the other two after randomized administration of a serotoninergic drug, fenfluramine (FF, 120 mg/day for 7 days) and FF plus ritanserin (RIT, 30 mg/day for the first 2 days and 20 mg/day on the following days). Ritanserin is a new selective 5-HT2 blocker receptor agent. Both controls and obese patients showed similar normal basal GH levels before each test and insulin administration always effectively reduced glucose levels to values lower than 2-2 mmol/l. In the controls, the expected GH increase to IIH (peak value 56 f 13.4 mU/1, AUC 234.4 f 55 mU/min/ml) was unaffected by FF administration (peak value 43 f 11.4;AUC 216.8 f 34.8). In response to the first IIH, the obese patients showed a significantly lower GH increase than in the case of the controls (peak valut 2 1 -4 f 4.6 mU/1, P < 0.02; AUC 93.2 f 18.6, P < 0.02). However, in comparison with the basal test, FF administration significantly ( P < 0.00 1) enhanced GH response to insulin hypoglycaemia (peak value 33.4 f 4; AUC 150 f 14.6), reaching values not significantly different from those of the controls. This effect was completely antagonized by RIT administration (peak value 18 f 5; AUC 85.6 f 2 1). In conclusion, the reduced GH response to insulin hypoglycaemia in obese women has been confirmed in the present study. However, the restoration of the hormonal response obtained after FF administration in obese patients only, which is effectively antagonized by RIT, strongly suggests the involvement of the serotoninergic system in this impaired

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