Insulin sensitivity and antiandrogenic therapy in women with polycystic ovary syndrome

Polycystic ovary (PCO) syndrome is strongly associated with insulin resistance and the accompanying adverse metabolic profile. To distinguish the mechanisms of this association, we determined the interactions of PCO with obesity and the influence of ameliorating direct androgenic actions via short-term treatment with the antiandrogen flutamide. Insulin sensitivity was determined by the hyperinsulinemic eugiycemic clamp in groups of lean and obese PCO women and weight-matched controls. Compared with control values, insulin-mediated glucose utilization in PCO women was significantly lower in lean (1.96 ± 0.17 v 1.24 ± 0.10, P < .01) and obese (1.23 ± 0.18 v 1.03 ± 0.09 mmol/m²/min, P < .01) subjects. ANOVA indicated that the effects of obesity and androgenicity are independent and additive. In both lean and obese PCO women, treatment with flutamide for 1 or 3 months markedly improved the clinical and biochemical androgenic features, but did not significantly influence the overall insulin sensitivity. A large disparity between individuals in the response to treatment correlated significantly with a simultaneous reduction in plasma levels of dehydroepiandrosterone sulfate (DHEA-S). Thus in women, PCO and obesity exert synergistic effects on insulin resistance. The decreased insulin sensitivity is mediated via indirect androgenic actions or nonandrogenic mechanisms. In some individuals, a direct effect of androgens might have been masked by a decrease in DHEA-S levels.