An abnormality of the growth hormone/insulin-like growth factor-I axis in women with polycystic ovary syndrome due to coexistent obesity

Abstract

In order to evaluate the GH/insulin-like growth factor-I (IGF-I) axis in the polycystic ovary syndrome (PCO), 21 women aged 18-38 yr were studied. The GH responses to the GH-releasing hormone (GHRH), and plasma concentrations of IGF-I were measured in seven obese women with PCO, seven obese healthy controls without PCO, and in seven nonobese subjects. Total GH secretion, as expressed by the integrated GH response to GHRH, in PCO obese women (617.4 +/- 150 micrograms/L.min) and in obese women without PCO (327.1 +/- 161.4 micrograms/L.min) were lower than that in nonobese healthy controls (3181.4 +/- 644.3 micrograms/L.min, P less than 0.001 and P less than 0.001, respectively). Plasma concentrations of IGF-I in obese PCO women (199.5 +/- 39.1 micrograms/L), and in obese women without PCO (192.4 +/- 36.8 micrograms/L) were similar to the IGF-I levels in nonobese controls (224.3 +/- 33.2 micrograms/L). In obese women with and without PCO, a negative correlation was found between the body mass index and the peak GH responses to GHRH (r = -0.639, P less than 0.02) and between age and IGF-I levels (r = -0.520, P less than 0.05). These findings suggest that an abnormality of the GH/IGF-I axis in PCO women may be due to coexistent obesity.