Evidence for the participation of endogenous opioids in the sympathoadrenal response to hypoglycaemia in man.

The effects of the long acting met-enkephalin analogue D-Ala2-MePhe4-met-enkephalin-O-ol (DAMME) and the opiate antagonist naloxone on the plasma catecholamine responses to insulin-induced hypoglycaemia have been investigated in two separate studies. DAMME depressed basal noradrenaline and adrenaline at 15 min, and blunted both the noradrenaline and adrenaline responses to hypoglycaemia. Naloxone did not alter basal plasma catecholamines, but caused a significant enhancement of the adrenaline response to hypoglycaemia. Neither DAMME nor naloxone altered the blood glucose response to insulin-induced hypoglycaemia. These data are consistent with an inhibitory modulation of endogenous opioids in the sympathoadrenal response to insulin-induced hypoglycaemia in man