Sex-specific differences in cortisol production rates in humans

Abstract

Production rates of cortisol were determined in healthy men (n = 7) and in healthy women during the follicular phase of their menstrual cycle (n = 7) using the stable-isotope dilution technique and analysis by gas chromatography/mass spectrometry (GC/MS). 1α,2α- d-Cortisol was infused for 10 hours (116 ± 6μg/h; 8 am to 6 pm). Blood samples obtained at 20-minute intervals during the last 4 hours (2 pm to 6 pm) were pooled and used for analysis. Estimated production rates of cortisol were 0.94 ± 0.15 mg/h and 0.38 ± 0.14 mg/h in healthy men and women, respectively. Even when corrected for body-surface area, production rates of cortisol in men (0.48 ± 0.09 mg/m 2 · h) were higher ( P < .001) than in women (0.22 ± 0.08 mg/m 2 · h). An increased production rate of cortisol was seen in 12 patients with Cushing's syndrome, although in four of nine female patients, it was within the range considered normal for healthy men. It is concluded that women have a lower production of cortisol than men and that this sex-specific difference is of clinical relevance in patients with endogenous hypercortisolism.