HPA axis function in obese women with PCOS
Ivana Bozic, Djuro Macut, Bojana Popovic, Tatjana Isailovic, Tamara Bogavac, Milan Petakov, Sanja Ognjanovic & Svetozar Damjanovic
Objectives: Besides well known increased adrenal androgen production, an enhanced peripheral cortisol metabolism was also observed in polycystic ovary syndrome (PCOS). This could induce a compensatory rise of ACTH secretion, tending to maintain normal plasma cortisol concentration at the expense of adrenal androgen excess. On the other hand, obesity is associated with a hyperactivity of the hypothalamicpituitaryadrenal (HPA) axis and impaired androgen balance. In this study we examined HPA axis sensitivity in obese women with PCOS.
Methods: Thirty-eight obese women with PCOS (age: 26.0±5.8 years, BMI: 32.3±4.7 kg/m2) and sixteen age and BMI matched obese healthy controls were examined. PCOS was diagnosed using ESHRE/ASRM criteria. In all subjects serum concentrations of glucose, insulin (with HOMA-IR calculation), C-peptide, testosterone, SHBG (with FAI calculation), DHEAS, leptin, adiponectin and basal cortisol were determined. Overnight dexamethasone supression test (0.5 mg) was performed in all women: 0.5 mg of dexamethasone was taken orally at 2300 h and blood samples for determination of cortisol were obtained at 0800 h the following day.
Results: There was no difference in glucose (P=0.95), insulin (P=0.30), HOMA-IR (P=0.45), C-peptide (P=0.23), leptin (P=0.40), adiponectin (P=0.09) and DHEAS (P=0.06) concentrations between groups. SHBG concentration (P=0.005) was significantly lower and testosterone (P=0.001), FAI (P<0.001) and androstenedion (P=0.046) concentrations were significantly higher in obese PCOS women than in obese controls. Obese PCOS had significantly higher basal cortisol concentrations then obese controls (452.8±151.5 vs 347.5±107.1 nmol/l; P=0.01). The percentage of cortisol suppression in response to 0.5 mg of dexamethasone was similar between obese PCOS and obese controls (81 vs 83%; P=0.31). Only in PCOS group, there was modest but statistically significant correlation between testosterone and cortisol concentrations (ρ=0.33, P=0.04).
Conclusion: Our results showed an increased basal cortisol concentration in obese PCOS in comparison to controls, and a possible alteration in the sensitivity of the adrenal glands to ACTH in obese woman with PCOS.