RELATIONS BETWEEN FASTING SERUM-INSULIN, GLUCOSE, AND DIHYDROEPIANDROSTERONE-SULFATE CONCENTRATIONS IN OBESE PATIENTS WITH HYPERTENSION - SHORT-TERM EFFECTS OF ANTIHYPERTENSIVE DRUGS

A randomized, single-blind, placebo-controlled study was conducted in 82 obese patients with mild to moderate essential hypertension, to det ermine the incidence of hyperinsulinemia, the relations between fastin g insulin and dihydroepiandrosterone-sulfate (DHEA-S) levels, and the short-term effects of antihypertensives on DHEA-S and insulin serum co ncentrations. Increased insulin/glucose ratios (IGR) suggestive of ins ulin resistance were found in half of our patients. Hyperinsulinemic a nd normoinsulinemic obese patients with hypertension had comparable fa sting glucose and DHEA-S concentrations and comparable blood pressure (BP) levels. Thus no relations were found between fasting insulin and DHEA-S levels. Fasting hyperinsulinemia was found in only half of the obese subjects with hypertension, suggesting that not all obese patien ts with hypertension are at the same high cardiovascular risk. Short-t erm treatment with captopril, prazosin, verapamil, atenolol, or hydroc hlorothiazide (HCTZ) reduced BP; greater BP reduction was observed wit h drugs with vasodilatory effects. Captopril, prazosin, and verapamil reduced fasting insulin levels, whereas atenolol and hydrochlorothiazi de did not. The former drugs reduced fasting insulin levels that were either within normal limits or in the hyperinsulinemic range. None of the drug treatments produced significant increases in serum DHEA-S con centrations, although some of them considerably reduced fasting insuli n levels. No relations between insulin and DHEA-S levels were observed either at baseline or at the end of the antihypertensive treatment. T he BP reduction resulting from the peripheral vasodilation may explain the insulin-reducing action of captopril, verapamil, and prazosin. Th ese results further emphasize the large heterogeneity present in the p athophysiologic mechanisms operating in obesity and hypertension.