Abstract
Objective: Glucose dependent insulinotropic peptide (GIP) belongs to the incretins which are
responsible for 70% of the insulin release after oral glucose intake. Its impaired
secretion was noted in several conditions involving insulin resistance, including
polycystic ovary syndrome (PCOS), known as the state with increased testosterone level.
This paper considers a possible relationship between the free androgen index (FAI)
and basal as well as meal stimulated level of GIP in lean women affected by PCOS.
To our knowledge, no previous study has evaluated the matter so far.
Design: cross-sectional study
Methods: 50 age-matched lean women (BMI=20.76±1.83) were enrolled to the study and divided
into 2 groups. Patients with phenotype with FAI<5 were classified as group 1, PCOS
patients with FAI>5 formed group 2. All subjects underwent standard meal test. Serum
GIP concentration was determined both at fasting and at 60 min of the test. Calculations
were carried out using Statistica 10.
Results: Mann-Whitney test indicated a statistically significant difference in medians values
of GIP plasma levels between groups on fasting (36.4 pg/ml vs. 59.6 pg/ml; p=0.0007) and at 60 min after meal test (50.1 pg/ml vs. 72.5 pg/ml; p=0.006). Spearman test indicated significant positive correlation between
FAI and GIP levels at 0’ and 60’ in total study population (0’:R=0.37;p=0.008; 60’:R=0.28;
p=0.049).
Conclusion: Excess androgen activity might be a factor contributing to alter secretion of incretins
in lean PCOS women. However it could not be ruled out that it is also possible that
increased GIP levels might induce hyperandrogenemia in PCOS. An increased GIP levels
may induce hyperinsulinemia and play an additive to insulin resistance role in progression
to diabetes mellitus type 2 (DMT2).
Key words
hyperandrogenemia - incretin - polycystic ovary syndrome - insulin resistance - diabetes
mellitus type 2
