AJP - Endocrinology and Metabolism, Vol 252, Issue 2 E255-E259, Copyright © 1987 by American Physiological Society
Beta-endorphin-induced hyperglycemia in rabbits: effects of a glucose or arginine challenge
R. L. Schleicher, R. K. Chawla, P. A. Coan, D. Martino-Saltzman and D. C. Collins
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)
