Beta-endorphin-induced hyperglycemia in rabbits: effects of a glucose or arginine challenge.
The effects of beta-endorphin on glucose, insulin, and glucagon levels were studied in normal fasted adult male rabbits. An intravenous bolus of glucose (0.7 g/kg body wt) produced a hyperglycemic state (peak plasma glucose 306 +/- 22 mg/dl; means +/- SE) that lasted approximately 90 min. beta-Endorphin (31 micrograms/g body wt; iv) administered immediately prior to the glucose challenge resulted in plasma glucose levels that were significantly higher from 10 to 90 min after the glucose challenge (P less than 0.001-0.05). From 10 to 30 min, plasma insulin levels were significantly lower in the beta-endorphin group (P less than 0.001-0.05), peaking at one-half the control group levels. Glucagon levels were unchanged by the glucose bolus in either the control or beta-endorphin-treated group (means +/- SE = 102.8 +/- 4 pg/ml). In another experiment, a 30-min infusion of L-arginine (13 mg-1 X kg body wt-1 X min iv) in normal fasted rabbits produced a rapid (10 min) increase in plasma insulin and glucagon and a return to base-line levels 60 min after withdrawing the arginine stimulus. Plasma glucose levels were not altered by arginine (mean +/- SE = 94.5 +/- 1 mg/dl). Administration of beta-endorphin (31 micrograms/kg body wt iv) at the start of the arginine infusion resulted in a rapid (10 min) and long-lasting (up to 60 min) hyperglycemic effect associated with a significant decrease in insulin levels (10-20 min; P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
D000818:Animals; D001120:Arginine / Q000494:pharmacology*; D001786:Blood Glucose / Q000378:metabolism*; D004723:Endorphins / Q000494:pharmacology*; D005934:Glucagon / Q000097:blood; D005947:Glucose / Q000494:pharmacology*; D007328:Insulin / Q000097:blood; D007700:Kinetics; D008297:Male; D011817:Rabbits; D001615:beta-Endorphin
D001786:Blood Glucose; D004723:Endorphins; D007328:Insulin; D001615:beta-Endorphin; D005934:Glucagon; D001120:Arginine; D005947:Glucose