Influence of body mass on the hypothalamic-pituitary-adrenal-axis response to naloxone in patients with polycystic ovary syndrome

Objective: To evaluate the influence of body mass on the hypothalamic- pituitary-adrenal (HPA)-axis response to naloxone in polycystic ovary syndrome (PCOS). Design: Controlled clinical study. Setting: Academic research environment. Patient(s): Ten lean and 10 obese women with PCOS compared with 7 lean and 8 obese control subjects matched for body mass index. Intervention(s): Each patient received an IV bolus of naloxone at a dosage of 125 μg/kg. Main Outcome Measure(s): Samples were collected 30 minutes before and 0, 15, 30, 60, 90, and 120 minutes after injection: ACTH and cortisol levels were measured in all plasma samples. Result(s): No significant differences were found in the ACTH and cortisol responses to opioid blockade between lean women with PCOS and lean as well as obese control subjects; conversely, obese patients with PCOS showed a higher ACTH and cortisol responses to naloxone compared with all other groups. Conclusion(s): Hypothalamic-pituitary-adrenal-axis abnormalities of PCOS may be central in origin and abdominal obesity seems to play a key role in the HPA-axis hyperactivity of women with PCOS when naloxone is administered.