24-hour serum cortisol profiles in women with polycystic ovary syndrome

We studied the 24-h blood profiles of cortisol in obese and non-obese women with polycystic ovary syndrome (PCOS), for comparison with the levels in healthy women (controls). The levels of other hormones, such as androgens, which are known to be disturbed in PCOS, were also compared. Luteinizing hormone (LH) and androgen (testosterone, androstenedione and dehydroepiandrosterone sulfate (DHEAS)) concentrations were significantly (p < 0.005) raised in patients with PCOS, compared to those in control women. Sex hormone binding globulin (SHBG) concentration was significantly lower in women with PCOS, particularly in those who were overweight. There was a significant negative correlation between body mass index (BMI) and SHBG concentrations (r = -0.59; p = 0.006). Mean 24-h cortisol concentrations were similar in women with PCOS and controls, as well as in the obese and non-obese PCOS patients. However, the 24-h blood cortisol profile pattern was significantly different in women with PCOS as compared to the controls (p = 0.0039). Significantly lower cortisol levels were observed during the night (levels were determined between 20.00 and 04.00 and are expressed as the area under the curve) in subjects with PCOS, compared to the control women (p = 0.02). These changes were most marked in the non-obese women with PCOS who had lower blood cortisol levels during the night than either the controls or the obese PCOS subjects. Our finding of significantly lower cortisol concentrations during the night could reflect a subtle abnormality of adrenal steroid secretion in women with PCOS.