The purpose of the present study was to gain a better insight in the mechanism of naloxone underlying the regulation of adrenal cortisol secretion in humans in vivo; therefore, the stimulatory effect of naloxone on cortisol secretion was assessed in a group of patients with hypothalamo-pituitary disconnection. Patients with hypothalamo-pituitary disconnection because of various pathologies (craniopharingioma, cordoma, suprasellar meningioma, or pituitary macroadenoma) participated in the study.
Results: Circulating cortisol, but not adrenocorticotropin (ACTH) levels were significantly higher after naloxone administration than after saline.
Conclusion: Besides the well-known hypothalamo-pituitary stimulatory action on ACTH release in normal humans, the results of the present study suggest that naloxone exerts direct effects on cortisol secretion at the adrenal gland level; another possibility is that naloxone stimulation of cortisol secretion is mediated by other factor than ACTH.
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