Different responses of insulin, C-peptide, and testosterone to an oral glucose tolerance test in two groups of women with polycystic ovarian syndrome

Background. To further investigate the relationship beta een inappropriate gonadotropin, hyperinsulinemia and androgen excess. Methods. We divided women with polycystic ovarian syndrome (PCOS) into two groups on the basis of LH/FSH (LH/FSH greater than or equal to 3, Group 1, n=30; LH/FSH<3. Group 2, n=25) and measured the responses of insulin, C-peptide (C-P), C-P/insulin (C-I) and testosterone concentrations to an oral glucose tolerance test (OGTT) in these patients and 15 control subjects. Results. Significant positive correlations were found between basal LH and T (r=0.58, p<0.05) in Group 1, and between Fasting serum insulin and T (r=0.48, p<0.05) in Group 2. Although these patients had higher, delayed insulin and C-P responses to OGTT than the control group, much greater insulin and C-P levels and lower C/I values were found in Group 2. T concentrations decreased mildly during OGTT in Group 1 and the control, while they increased slightly in Group 2. Conclusion. Our data suggest that hyperinsulinemia in PCOS is due to a enhanced beta-cell secretion and an impaired hepatic clearance of this hormone, hyperandrogenism may be LH-dependent in Group 1 and insulin-dependent in Group 2.