Differential male and female adrenal cortical steroid hormone and cortisol responses to interleukin-6 in humans

: Evidence from experimental animal studies show that sex hormones influence the glucocorticoid response to a variety of inflammatory and noninflammatory stimuli. In this study we assessed gender differences in the response of ACTH and cortisol in normal young male and female humans following intravenous infusion of human IL-6 in various dosages. Males presented a significantly stronger ACTH production in response to IL-6 than females. Peak cortisol response, however, was similar in males and females. Cortisol/ACTH ratios were significantly higher in females than in males, both at baseline and after each of the IL-6 dosages. These results suggest that an effective glucocorticoid response requires similar levels of IL-6 in males and females. However, they also suggest that the adrenals of males and females have different sensitivities to ACTH (higher in females) and possibly also to direct IL-6 stimulation.