AJP - Renal Physiology, Vol 252, Issue 1 138-F145, Copyright © 1987 by American Physiological Society
Glucose metabolism in muscle of sedentary and exercised rats with azotemia
T. A. Davis, S. Klahr and I. E. Karl
Insulin resistance has been demonstrated in chronic renal failure patients
and may be improved by exercise training, but the mechanisms have not been
identified. In this study, the response of glucose uptake, glycogen
synthesis, and glucose utilization via glycolysis (glycolytic utilization)
to stimulation by insulin and/or acute exercise were determined in isolated
muscles from rats with moderate renal insufficiency that were exercise
trained or remained sedentary. Moderate renal insufficiency had no effect
on the basal rate, insulin sensitivity, or insulin responsiveness of
glucose uptake, glycogen synthesis, or glycolytic utilization in muscle.
The enhanced insulin responsiveness of both glycogen synthesis and glucose
uptake following acute exercise, noted in control animals, was less in rats
with moderate renal insufficiency, but the enhanced basal rate and insulin
sensitivity after exercise were unaffected by moderate renal insufficiency.
Exercise training increased the insulin sensitivity and responsiveness of
muscle glucose uptake and glycolytic utilization in rats with moderate
renal insufficiency and in controls. The effects of acute exercise and
exercise training on insulin responsiveness of glucose uptake were additive
in controls but not in animals with moderate renal insufficiency. These
findings are compatible with the concept that moderate renal insufficiency
is associated with a postreceptor defect in insulin's action in muscle,
detectable only following maximal stimulation of glucose transport by
insulin and exercise, and partially correctable by exercise training.
