Beta-endorphin and islet hormone release in type-2 diabetes mellitus the effects of normoglycemia, enkephalin, naloxone and somatostatin.
The present study was aimed at characterizing the effects of beta-endorphin on plasma glucose, insulin and glucagon plasma levels in subjects with type-2 diabetes mellitus. Infusion of 0.5 mg/h human beta-endorphin produced significant and simultaneous increments in both insulin and glucagon concentrations and decreased plasma glucose levels (-18 +/- 4 mg/dl, 60 min level, p less than 0.01). When the same diabetics were rendered euglycemic by an insulin infusion (1 mU/kg/min), beta-endorphin did not produce the expected decrease in plasma glucose concentrations nor raise plasma insulin levels; only the response of glucagon was preserved. Normal subjects were rendered hyperglycemic by an intravenous glucose infusion to match the plasma glucose levels of diabetic subjects. In this condition, beta-endorphin produced a significant increase of insulin concentrations, whereas glucagon remained suppressed. The intravenous administration of the long-acting met-enkephalin analogue DAMME (0.25 mg) blunted the hormonal responses to the subsequent beta-endorphin infusion in diabetic patients, although the inhibition was short-lived (30-40 min). Naloxone (5 mg), an opiate antagonist, did not produce any significant change in the insulin and glucagon responses to beta-endorphin, while somatostatin (0.25 mg/h) completely abolished the hormonal responses to the opioid.(ABSTRACT TRUNCATED AT 250 WORDS)
D001786:Blood Glucose / Q000378:metabolism; D005405:D-Ala(2),MePhe(4),Met(0)-ol-enkephalin / Q000494:pharmacology; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology*; D005260:Female; D005934:Glucagon / Q000378:metabolism*; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D009270:Naloxone / Q000494:pharmacology; D013004:Somatostatin / Q000494:pharmacology; D001615:beta-Endorphin / Q000494:pharmacology*
D001786:Blood Glucose; D007328:Insulin; D009270:Naloxone; D013004:Somatostatin; D001615:beta-Endorphin; D005405:D-Ala(2),MePhe(4),Met(0)-ol-enkephalin; D005934:Glucagon