An abnormality of the growth hormone/insulin-like growth factor-I axis in women with polycystic ovary syndrome.

Abstract

To investigate the GH/insulin-like growth factor-I (IGF-I) axis in women with polycystic ovary syndrome (PCO), we measured serum concentrations of GH over a 14-h period (0900-2300 h) in 10 women with this disorder using an ambulatory exfusion pump. The same study was carried out in 9 age- and weight-matched normal cycling women who served as controls. Mean (+/- SE) serum GH concentrations over the 14-h period were markedly lower in the subjects with PCO (0.6 +/- 0.2 vs. 1.8 +/- 0.3 micrograms/L; P less than 0.005). Eight of 10 subjects with PCO had mean serum GH concentrations below 1.2 micrograms/L, while only 1 of 9 control subjects had corresponding values below this concentration. In contrast, mean circulating serum concentrations of IGF-I were indistinguishable in the 2 groups. We conclude from these data that PCO is characterized by decreased serum GH concentrations in the face of normal serum IGF-I concentrations. The mechanisms underlying this alteration in the GH/IGF-I axis and its role in the pathogenesis of PCO remain to be clarified.