AJP - Endocrinology and Metabolism, Vol 248, Issue 3 327-E332, Copyright © 1985 by American Physiological Society
Glucose turnover during insulin-induced hypoglycemia in liver-denervated rats
K. J. Mikines, B. Sonne, E. A. Richter, N. J. Christensen and H. Galbo
The role of hepatic autonomic nerves in glucose production during
hypoglycemia was studied. Selective, surgical denervation of the liver was
performed in rats, which reduced hepatic norepinephrine concentrations by
96%. Hypoglycemia was induced by 250 mU of insulin intra-arterially in
anesthetized as well as in chronically catheterized, awake rats. Half of
the anesthetized denervated or sham-operated rats had previously been
adrenodemedullated. Glucose turnover was measured by primed, constant
intravenous infusion of [3-3H]glucose. Before as well as during
hypoglycemia the arterial glucose concentration and rates of production and
utilization of glucose were similar in denervated rats and control rats.
Also hepatic glycogen depletion was similar in the groups. The lack of
effect of denervation could not be ascribed to compensating changes in
hormone or substrate levels. In adrenodemedullated rats lack of glucose
recovery from hypoglycemia was accompanied by delayed normalization of
glucose clearance. In fed rats, activity in hepatic autonomic nerves is not
a primary mechanism increasing glucose production during acute
hypoglycemia. Epinephrine enhances glucose recovery by decreasing glucose
clearance rather than by increasing glucose production, at least when
glucagon is present.
