Growth hormone secretion is impaired but not related to insulin sensitivity in non-obese patients with polycystic ovary syndrome

Background: The aim of the study was to elucidate the relationship between growth hormone (GH) secretion and insulin resistance in polycystic ovary syndrome (PCOS) patients. In order to exclude the influence of obesity on these parameters, only non-obese PCOS patients were studied. Methods: Eleven PCOS patients and 11 controls with a body mass index (BMI) less than or equal to25 kg/m(2) were studied. PCOS patients were studied on cycle day 14-15, controls on cycle day 5-9. GH secretion was determined by frequent sampling, from 20.00 h to 08.00 h. Insulin sensitivity was determined by a euglycaemic hyperinsulinaemic clamp and was expressed as the M-value. Insulin-like growth factor-1 (IGF-1) and IGF-binding protein-3 (IGFBP-3) levels were determined once. Results: Pooled GH levels were significantly lower in PCOS patients than controls, as was GH pulse amplitude. The number of GH pulses was not different between PCOS patients and controls. The M-value was significantly lower in PCOS patients, although a wide overlap between patients and controls was present. IGF-1 and IGFBP-3 levels were not different between the groups. There was no correlation between the M-value and pooled GH or IGF-1 and IGFBP-3 levels. Conclusion: Non-obese patients with PCOS have impaired GH secretion and some but not all have impaired insulin sensitivity. These findings indicate that these patients may also be at risk for cardiovascular diseases and/or diabetes mellitus.