AJP - Endocrinology and Metabolism, Vol 250, Issue 4 393-E401, Copyright © 1986 by American Physiological Society
Glucoregulatory role of cortisol and epinephrine interactions studied in adrenalectomized dogs
C. Gauthier, K. el-Tayeb, M. Vranic and H. L. Lickley
The importance of basal cortisol (H) and epinephrine (E) levels on
glucoregulation, and the effects of E, given to simulate moderate to severe
stress (5 times basal rate of infusion), were examined in seven conscious
adrenalectomized dogs. Although plasma glucagon (IRG) increased by 47%,
insulin (IRI) decreased by 36%, norepinephrine (NE) increased by 103%, and
FFA decreased by 26%, glucose concentration and kinetics remained normal
after adrenalectomy. A 4-h infusion of H reestablished basal cortisol
levels and returned IRG to its basal preadrenalectomy level with no change
in IRI, NE, and FFA levels. Glucose production and metabolic clearance
decreased concomitantly by 20%, maintaining euglycemia. A 90-min infusion
of basal E caused only a transient increase in IRG. The simultaneous
infusion of H with E prevented this increase in IRG and returned IRI to
preadrenalectomy levels in the absence of any change in NE or glucose. A
subsequent infusion of five times basal E, alone, raised circulating E
levels and caused a transient decrease in plasma NE, but no change in IRI.
There was a similar hyperglycemic response, as seen previously in normal
dogs. The simultaneous infusion of H and E prevented the decrease in NE,
but did not change the IRI and FFA responses. There was an 80% greater
plasma glucose response than seen during infusion of E alone. In
conclusion, what E and H lack after adrenalectomy is compensated for by an
increase in IRG and a decrease in IRI, and normal glucose concentrations
and kinetics are maintained. It appeared that normoglucagonemia required
basal H release, whereas normoinsulinemia required both basal H and E
secretion.(ABSTRACT TRUNCATED AT 250 WORDS)
