AJP - Endocrinology and Metabolism, Vol 246, Issue 3 232-E236, Copyright © 1984 by American Physiological Society
Chronic norepinephrine infusion and insulin and glucagon secretion in the dog
W. J. Raum, R. S. Swerdloff, D. Garner, H. Laks and M. M. Laks
The effect of epinephrine on glucose homeostasis has been studied
extensively in many species, but there is little data on the effects of
another catecholamine, norepinephrine. This study was designed to examine
the alterations that occur in insulin and glucagon secretion during a
chronic low-dose infusion of norepinephrine in free-roaming dogs. A total
of four intravenous glucose tolerance tests and insulin-induced
hypoglycemia tests were performed on each of five dogs infused with
norepinephrine (1.4 g/min) for 3 mo and on each of eight control dogs. The
infusion resulted in a threefold increase in plasma norepinephrine without
a significant effect on blood pressure. Fasting serum glucose was elevated
significantly in the norepinephrine-infused dogs [102.4 +/- 2.1 vs. 92.8
+/- 1.7 (SE) mg/100 ml]. Fasting plasma glucagon was elevated by the
norepinephrine infusion (58.4 +/- 7.6 vs. 31.3 +/- 3.1 pg/ml), whereas
fasting serum insulin was inhibited (12.3 +/- 1.3 vs 16.8 +/- 1.7 U/ml).
Glucagon secretion in response to hypoglycemia was markedly enhanced in the
infused dogs compared with controls. It has been reported that the infusion
of norepinephrine in humans will inhibit insulin secretion and increase
serum glucose concentrations but have no effect on serum glucagon
concentrations. The stimulation of glucagon by norepinephrine has been
demonstrated in the isolated, perfused canine pancreas but has not been
reported previously in the free-roaming dog.
