Effect of opioid blockade on insulin and growth hormone (GH) secretion in patients with polycystic ovary syndrome: the heterogeneity of impaired GH secretion is related to both obesity and hyperinsulinism

Objective: To investigate the involvement of opioid tone, obesity, and hype rinsulinemia in GH secretion in women with polycystic ovary syndrome (PCOS) . Design: Controlled clinical study. Setting: Catholic University of Sacred Heart School of Medicine in Pome, It aly. Patient(s): Twenty-two patients with PCOS and 14 healthy, normally ovulatin g volunteers, matched for age and body mass index. Intervention(s): Patients underwent a GH-releasing hormone (GHRH) test and an oral glucose tolerance test before and after 4-5 weeks of treatment with 50 mg/d of naltrexone. Main Outcome Measure(s): Serum concentrations of GH, insulin, glucose, ster oids, and gonadotropins, as well as the GH area under the curve (AUC-GH) an d the insulin area under the curve (AUC-I), were measured before and after naltrexone treatment. Result(s): In patients with PCOS, the administration of naltrexone increase d the GH response to the GHRH test without interfering with the insulin res ponse to the oral glucose tolerance test. However, the GH response to the G HRH test was improved significantly only in lean patients with PCOS, wherea s obese patients with PCOS did not show any improvement in GH secretion. In obese control subjects, the treatment reduced plasma basal insulin concent rations and increased the AUC-GH, whereas in lean control subjects, the tre atment reduced the GHRH-induced response. In normoinsulinemic patients with PCOS, the GH response to the GHRH test increased significantly after treat ment, whereas the AUG-I was not affected. In hyperinsulinemic patients with PCOS, treatment with naltrexone significantly reduced the AUG-I, whereas t he AUC-GH increased only in lean hyperinsulinemic patients with PCOS. Conclusion(s): Naltrexone treatment improves GHRH-induced GH secretion in p atients with PCOS. However, this GH response is heterogeneously represented in relation to both obesity and hyperinsulinism. (C) 1998 by American Soci ety for Reproductive Medicine.