Opioid-receptor blockade blunts growth hormone (GH) secretion induced by GH-releasing hormone in the human male.
OBJECTIVE
To investigate the existence of an opioid stimulatory tone on growth hormone (GH) secretion in the human male.


METHODS
Seven healthy male volunteers, aged 19-30, were studied in the Endocrine Unit of the University of Sassari. GH-releasing hormone (GHRH), 100 micrograms as an intravenous (IV) bolus, as administered with and without preadministration of IV naloxone, 2 mg as a bolus followed by a constant infusion of 2 mg/h. Blood samples were taken for 120 minutes after GHRH administration.


RESULTS
Naloxone significantly blunted the GH response to GHRH, measured either as mean peak value (at times 30 to 90) or as integrated concentrations.


CONCLUSIONS
Naloxone is able to decrease the effect of a maximal dose of GHRH, thus suggesting the existence of an opioid stimulatory tone on GH secretion.
Tomasi
P A
PA
Istituto di Ematologia e di Endocrinologia, Universitá di Sassari, Italy.
Fanciulli
G
G
Palermo
M
M
Pala
A
A
Demontis
M A
MA
Delitala
G
G
D000328:Adult; D013007:Growth Hormone-Releasing Hormone / Q000494:pharmacology*; D019382:Human Growth Hormone / Q000097:blood*; D006801:Humans; D008297:Male; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology
D009292:Narcotic Antagonists; D019382:Human Growth Hormone; D009270:Naloxone; D013007:Growth Hormone-Releasing Hormone