AJP - Endocrinology and Metabolism, Vol 246, Issue 2 181-E186, Copyright © 1984 by American Physiological Society
Inhibitory effect of plasma free fatty acids on glucose production in the conscious dog
R. R. Wolfe and J. H. Shaw
We have previously reported that, in conscious, unrestrained dogs in which
insulin and glucagon levels were clamped pharmacologically, combined alpha-
and beta-adrenergic blockade resulted simultaneously in a fall in plasma
free fatty acid (FFA) levels and an increase in glucose production. In this
study we have tested the hypothesis that the increase in glucose production
observed in the previous study was due to the fall in plasma FFA
concentration. Glucose production was measured by means of the
primed-constant infusion of [6-3H]- and/or [U-14C]glucose, and insulin and
glucagon were clamped at constant levels by means of the infusion of
somatostatin, insulin, and glucagon. When no attempt was made to control
the FFA levels, combined alpha- and beta-adrenergic blockade significantly
decreased plasma FFA levels, and this was associated with a significant
increase in the rate of glucose production. However, the glucose production
response to adrenergic blockade was entirely prevented by the clamping of
FFA levels at a high, constant value by the infusion of a 10% lipid
emulsion (Liposyn) and heparin. We conclude that basal adrenergic activity
is important in the mobilization of fat but does not directly influence
glucose production. Further, there is an inhibitory effect of FFA on
glucose production that is unmasked during hormonal control and alpha- and
beta-adrenergic blockade.
