AJP - Endocrinology and Metabolism, Vol 252, Issue 5 E660-E666, Copyright © 1987 by American Physiological Society
Non-insulin-mediated glucose uptake predominates in postabsorptive dogs
M. Lavelle-Jones, M. H. Scott, O. Kolterman, A. R. Moossa and J. M. Olefsky
Overall glucose uptake represents the sum of insulin-mediated glucose
uptake (IMGU) and non-insulin-mediated glucose uptake (NIMGU). In this
study, we compared the rate of NIMGU in conscious and anesthetized dogs.
Rates of glucose disposal were compared in the basal state and during
severe insulinopenia after endogenous insulin suppression by high-dose
somatostatin (SRIF) infusion. Steady-state NIMGU rates were calculated 2 h
after commencing SRIF infusion. Three groups of studies were performed: 1)
SRIF in conscious dogs; 2) SRIF in anesthetized dogs; and 3) SRIF plus
glucagon, also in anesthetized dogs. In all three groups, serum insulin
levels were reduced to below assay sensitivity after SRIF infusion. The
basal metabolic clearance rate of glucose (MCRg) for each group was 3.8 +/-
0.4, 3.6 +/- 0.3, and 3.6 +/- 0.3 ml X kg-1 X min-1, respectively (P = NS,
all groups). Steady-state NIMGU rates were 2.4 +/- 0.2 (conscious), 2.5 +/-
0.1 (anesthetized, SRIF only), and 2.4 +/- 0.1 ml/kg/min (anesthetized,
SRIF plus glucagon). Thus, absolute rates of NIMGU expressed as MCRg in
conscious and anesthetized animals do not differ and in the three groups
studied comprise approximately the same proportion of the basal glucose
uptake (approximately 64, approximately 69, and approximately 66%,
respectively). We conclude that approximately 66% of basal postabsorptive
glucose uptake occurs via NIMGU mechanisms and that this pathway is
unaffected by anesthesia and surgery.
