Effect of naloxone on oxytocin-induced cortisol decrease in normal men

V. Coiro, P. Chiodera, G. Rossi, R. Volpi, M. Salvi, L. Camellini, E. Roti

Research output: Contribution to journalArticlepeer-review


Iv administration of oxytocin decreases plasma ACTH-cortisol levels in normal men. In contrast, naloxone, a specific opioid antagonist, stimulates cortisol release, suggesting that opioid peptides exert an inhibitory control on ACTH-cortisol secretion. The present study was carried out in an attempt to determine whether an opioid pathway mediates oxytocin action; therefore, we evaluated the effect of naloxone on the decrease of cortisol induced by oxytocin. Six normal men were treated iv with oxytocin (2 IU as a bolus), naloxone (4 mg as a bolus plus 10 mg infused for 2 h) or a combination of the 2 drugs. Plasma cortisol levels were determined in samples taken before and 2 h after drug treatment. As expected, administration of oxytocin significantly decreased cortisol secretion, while naloxone had a stimulatory effect on plasma cortisol levels. When oxytocin injection was followed by administration of naloxone, cortisol levels remained unchanged; thus, naloxone abolished a cortisol decrement in response to oxytocin. These findings show that in man oxytocin requires an active opioid system in order to produce its inhibitory action on ACTH-cortisol secretion, suggesting that this effect of oxytocin could be mediated by an opioid pathway.

Original languageEnglish
Pages (from-to)261-265
Number of pages5
JournalActa Endocrinologica
Issue number2
Publication statusPublished - 1985

ASJC Scopus subject areas

  • Endocrinology


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