AJP - Gastrointestinal and Liver Physiology, Vol 251, Issue 3 341-G348, Copyright © 1986 by American Physiological Society
Effects of glucose-insulin-potassium on intestinal hemodynamics and substrate utilization during endotoxemia
C. H. Lang and R. J. Alteveer
This study examined the effects of endotoxin on small intestinal
hemodynamics and metabolism with and without an infusion of
glucose-insulin-potassium (GIK). Glucose uptake and lactate release were
determined by arteriovenous differences across a segment of canine ileum,
which was vascularly isolated in vivo, and by the direct measurement of
intestinal blood flow. Free fatty acid (FFA) utilization by intestinal
tissue was assessed by the constant infusion of albumin-bound
[14C]palmitate and [3H]oleate. Endotoxemic dogs showed a sustained
reduction of mean arterial blood pressure (MABP) and intestinal blood flow.
In contrast, endotoxemic dogs infused with GIK demonstrated a decreased
intestinal vascular resistance and an increased blood flow (two-fold),
whereas MABP was transiently improved. Intestinal glucose uptake was not
different from control values in endotoxemic animals; however, a sixfold
increase was seen in shocked dogs treated with GIK. The endotoxin-induced
increase in the plasma lactate concentration and intestinal lactate release
was similar between dogs infused with saline or GIK. After endotoxin, the
arterial FFA concentration remained unchanged and whole-body FFA turnover
was decreased. FFA uptake by the gut was reduced, but FFA oxidation was not
altered. Similar changes in FFA metabolism were seen in endotoxemic animals
infused with GIK. The metabolic pattern after endotoxin suggests an
elevated rate of aerobic glycolysis by the gut that increases the
availability of lactate to the liver. Compared with saline-infused
endotoxemic animals, GIK produced an elevation in glucose uptake without a
further increase in lactate output, suggesting an increased storage of
glucose by this tissue.
