Lack of effect of beta-endorphin on basal or glucagon-stimulated hepatic glucose production in vitro.
beta-Endorphin appears to have effects on hepatic glucose production in vivo. In order to determine whether beta-endorphin modulates glucose production directly, the effects of beta-endorphin on isolated rat hepatocytes were investigated. This permitted isolation of the effects of beta-endorphin from hormonal and/or neuronal influences. A significant dose-related stimulatory effect of glucagon (10(-10) to 10(-6) mol/L) on both hepatic glucose production and glycogen phosphorylase a activity was demonstrated. No effect of either physiologic (10(-11) to 10(-9) mol/L) or supraphysiologic (10(-6) mol/L) concentrations of beta-endorphin on these parameters, under basal or glucagon-stimulated conditions, could be detected. These results suggest that reported in vivo effects of beta-endorphin to inhibit hepatic glucose production were either indirect or centrally mediated.
D000818:Animals; D004723:Endorphins / Q000494:pharmacology*; D005934:Glucagon / Q000494:pharmacology*; D005947:Glucose / Q000096:biosynthesis*; D066298:In Vitro Techniques; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D010762:Phosphorylase a / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D001615:beta-Endorphin
D004723:Endorphins; D001615:beta-Endorphin; D005934:Glucagon; D010762:Phosphorylase a; D005947:Glucose