Insulin, C-peptide, androgens, and beta-endorphin response to oral glucose in patients with polycystic ovary syndrome.

We examined the effects of an oral glucose load on plasma insulin, androgens, and beta-endorphin (beta EP) concentrations in patients carefully selected as having polycystic ovary syndrome (PCOS) and normal glucose tolerance. Our aim was to verify whether insulin resistance is a common feature of PCOS and to differentiate the metabolic abnormalities related to PCOS from those associated with obesity. Plasma immunoreactive insulin (IRI), C-peptide (C-PR), testosterone, androstenedione, dehydroepiandrosterone sulfate, ACTH, and beta EP responses to a 3-h oral glucose tolerance test (OGTT) were evaluated in 10 obese (OB-PCOS) and 10 nonobese (NO-PCOS) patients with PCOS and in 7 obese and 7 nonobese ovulatory controls. OB-PCOS and NO-PCOS did not differ significantly from weight-matched controls in the IRI response, but had a significantly higher C-PR response in terms of mean postglucose load levels and mean incremental areas. During OGTT, mean plasma levels of testosterone, androstenedione, and dehydroepia...