Metabolic and Endocrine Consequences of Acute Suppression of FFAs by Acipimox in Polycystic Ovary Syndrome

To evaluate the effects of acute lowering of FFAs on glucose-induced insulin secretion and GH response to GHRH in polycystic ovary syndrome (PCOS), 27 PCOS subjects (11 lean and 16 obese) and 17 body mass index-matched controls (8 lean and 9 obese) were investigated. Patients underwent an oral glucose tolerance test and a GHRH test before and after administration of the antilipolytic drug acipimox (250 mg orally 3 h and 1 h before the starting of the tests). Blood samples were collected for 2 h after GHRH bolus and for 4 h after the oral glucose tolerance test. Serum concentrations of GH, insulin, glucose, and c-peptide were assayed in each sample, and the results were expressed as area under the curve (AUC). No significant differences were found as to glucose, insulin, and c-peptide AUC before and after acute FFA plasma reduction in any of the investigated groups. Basally, lower GH-AUC was found in lean PCOS compared with body mass index-matched controls and in obese vs. lean controls; no significant differences were found as to the same variable between the two obese groups. The acipimox induced FFA suppression elicited in the four groups a sustained increase in the GH response to its trophic hormone; indeed, the GH-AUC nearly doubled with respect to basal evaluation in all the studied groups. However, the antilipolytic drug was not able to abolish the differences found between lean groups in basal conditions. In conclusion, the presented data confirm that FFAs have a main role in regulating GH secretion at the pituitary level; however, it does not seem that they could explain the GH as well as insulin dysfunction of PCOS.