Naloxone potentiation of 2-Br-alpha-ergocryptine (CB 154) effects on GH secretion in man

The effect of the combined administration of either CB 154 (2.5 mg/osM) or L-DOPA (500 mg/osM) and naloxone have been studied in six normal male volunteers. Naloxone cause a clear-cut potentiation of CB 154 effects on human growth hormone (hGH) secretion and only a slight, statistically non-significant, potentiation of L-DOPA effects on hGH secretion. These results have been discussed in the light of morphofunctional findings showing possible interactions between dopamine (DA) systems and somatostatin-positive and enkephalin-positive nerve terminals.