Central effects of beta-endorphins on glucose homeostasis in the conscious dog.
The effects of centrally administered beta-endorphins on glucose homeostasis in the conscious dog were studied. Intracerebroventricular administration of beta-endorphin (0.2 mg/h) caused a 70% increase in plasma glucose. The mechanism of the hyperglycemia was twofold: there was an early increase in glucose production and a late inhibition of glucose clearance. These changes are explained by marked increases in plasma epinephrine (30-fold) and norepinephrine (6-fold) that occurred during infusion of beta-endorphin. Central administration of beta-endorphin also resulted in increased levels of adrenocorticotropic hormone and cortisol. In addition there was an increase in plasma insulin but no increase in plasma glucagon. Intravenous administration of beta-endorphin did not alter glucose homeostasis. Intracerebroventricular administration of acetylated beta-endorphin did not perturb glucose kinetics or any of the hormones that changed during infusion of the unacetylated peptide. We conclude that beta-endorphin acts centrally to cause hyperglycemia by stimulating sympathetic outflow and the pituitary-adrenal axis. Acetylation of beta-endorphin abolishes the in vivo activity of the peptide.
Radosevich
P M
PM
Department of Surgery, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
Lacy
D B
DB
Brown
L L
LL
Williams
P E
PE
Abumrad
N N
NN
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002552:Cerebral Ventricles / Q000187:drug effects / Q000502:physiology*; D004285:Dogs; D004837:Epinephrine / Q000097:blood; D005260:Female; D005934:Glucagon / Q000097:blood; D005947:Glucose / Q000378:metabolism*; D006706:Homeostasis / Q000187:drug effects; D007276:Injections, Intraventricular; D007328:Insulin / Q000097:blood; D007700:Kinetics; D008297:Male; D008954:Models, Biological; D009638:Norepinephrine / Q000097:blood; D012016:Reference Values; D014316:Tritium; D001615:beta-Endorphin / Q000008:administration & dosage / Q000494:pharmacology*
D001786:Blood Glucose; D007328:Insulin; D014316:Tritium; D001615:beta-Endorphin; D005934:Glucagon; D005947:Glucose; D009638:Norepinephrine; D004837:Epinephrine