Objective: To assess the effects of the administration of exogenous ghrelin, a peptide with potent GH-releasing activity and glucose-enhancing and insulin-lowering properties, in obese patients with polycystic ovary syndrome (PCOS).
Design: Prospective, controlled study.
Setting: Academic research environment.
Patient(s): Twenty obese women with PCOS, and 15 obese controls.
Intervention(s): Oral glucose tolerance test (OGTT) and ghrelin test (1 microg/kg i.v. bolus).
Main outcome measure(s): Basal hormonal assays, including ghrelin, were performed. Glucose, insulin, and C-peptide were assessed in a fasting condition and during the OGTT. Growth hormone, insulin, and glucose were measured basally and every 15 minutes for 90 minutes after the injection of ghrelin.
Result(s): Both groups showed an insulin response to the glucose load above the normal range. Significantly lower levels of ghrelin were detected in patients with PCOS compared to controls (108.96 +/- 27.65 Fmol/mL versus 162.47 +/- 42.23 Fmol/mL). Administration of ghrelin markedly enhanced GH levels in both groups (1,888.59 +/- 1,209.53 ng/mL and 1,639.95 +/- 631.79 ng/mL per 90 minutes as GH area under the curve, respectively), with a peak occurring 30 minutes after injection. Ghrelin also induced a trend toward an increase in plasma glucose levels, and a significant decrease in insulin concentrations in both groups.
Conclusion(s): The injection of ghrelin seems to override the GH secretion defect in obese women with PCOS, and to induce glucoinsulinemic changes in both controls and obese patients with PCOS.