Objective: Polycystic ovary syndrome (PCOS) has been linked to a high risk of type 2 diabetes mellitus. Disturbances in the secretion of the incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) have been observed in states with impaired glucose regulation. This paper considers the secretion of GIP and GLP-1 after oral glucose load in a group of lean, glucose-tolerant PCOS women in comparison with age- and body mass index (BMI)-matched healthy women.
Design: Case control.
Methods: PCOS (n=21, 25.8+/-4.1 years, BMI 21.6+/-1.7 kg/m(2)) and control healthy women (CT, n=13, 28.5+/-7.2 years, BMI 20.3+/-2.5 kg/m(2)) underwent oral glucose tolerance test (OGTT) with blood sampling for glucose, insulin, C-peptide, total GIP, and active GLP-1. Insulin sensitivity was determined both at fasting and during the test.
Statistics: Repeated measures ANOVA.
Results: Glucose levels and insulin sensitivity did not differ between PCOS and CT. PCOS had significantly higher levels of C-peptide (P<0.05) and tended to have higher insulin levels. The levels of total GIP were significantly higher in PCOS than in CT (P<0.001). Active GLP-1 levels exhibited a significantly different time-dependent pattern in PCOS (P<0.002 for PCOS versus time interaction). GLP-1 concentrations were similar in PCOS and CT in the early phase of OGTT and then reached significantly lower levels in PCOS than in CT at 180 min (P<0.05).
Conclusions: Increased total GIP and lower late phase active GLP-1 concentrations during OGTT characterize PCOS women with higher C-peptide secretion in comparison with healthy controls, and may be the early markers of a pre-diabetic state.