AJP - Endocrinology and Metabolism, Vol 250, Issue 6 607-E614, Copyright © 1986 by American Physiological Society
Synergistic improvement of glucose tolerance by sucrose feeding and exercise training
A. L. Vallerand, J. Lupien and L. J. Bukowiecki
The interactive effects of exercise training (5-7 wk) and sucrose
consumption (ad libitum feeding of a 32% sucrose solution and Purina chow)
on intravenous glucose tolerance and plasma insulin levels were
investigated using a 2 X 2 experimental design. Rats were divided in
Purina-sedentary, Purina-trained, sucrose-sedentary, and sucrose-trained
groups. Sucrose feeding of sedentary animals significantly increased basal
and glucose-stimulated insulin levels and improved basal glycemia and
glucose tolerance. On the other hand, exercise training of Purina-fed
animals significantly reduced basal as well as glucose-stimulated
insulinemia without altering basal glycemia or glucose tolerance. Such a
sparing effect of exercise training on insulin requirements was not as
evident in rats consuming sucrose. These animals displayed a reduced basal
glycemia (P less than 0.01) with normal basal insulin levels. Their glucose
tolerance was markedly improved (P less than 0.01) but their insulin
response during intravenous glucose tolerance test remained as high as in
sucrose-sedentary animals. Results from these studies indicate that sucrose
feeding of sedentary animals leads to hyperinsulinemia without compensatory
insulin resistance, resulting in an improvement of glucose tolerance,
exercise training increases the sensitivity of peripheral tissues to
insulin, and the marked improvement of glucose tolerance observed in
sucrose-trained animals results from a synergistic combination of the above
two factors, i.e., increased insulinemia (induced by diet) and enhanced
insulin sensitivity (induced by training).
