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Effect of increased blood glucose availability on glucose kinetics during exercise

journal contribution
posted on 1998-04-01, 00:00 authored by Kirsten HowlettKirsten Howlett, D Angus, J Proietto, Mark Hargreaves
This study examined the effect of increased blood glucose availability on glucose kinetics during exercise. Five trained men cycled for 40 min at 77 ± 1% peak oxygen uptake on two occasions. During the second trial (Glu), glucose was infused at a rate equal to the average hepatic glucose production (HGP) measured during exercise in the control trial (Con). Glucose kinetics were measured by a primed continuous infusion ofd-[3-3H]glucose. Plasma glucose increased during exercise in both trials and was significantly higher in Glu. HGP was similar at rest (Con, 11.4 ± 1.2; Glu, 10.6 ± 0.6 μmol ⋅ kg−1 ⋅ min−1). After 40 min of exercise, HGP reached a peak of 40.2 ± 5.5 μmol ⋅ kg−1 ⋅ min−1in Con; however, in Glu, there was complete inhibition of the increase in HGP during exercise that never rose above the preexercise level. The rate of glucose disappearance was greater (P < 0.05) during the last 15 min of exercise in Glu. These results indicate that an increase in glucose availability inhibits the rise in HGP during exercise, suggesting that metabolic feedback signals can override feed-forward activation of HGP during strenuous exercise.

History

Journal

Journal of applied physiology

Volume

84

Issue

4

Pagination

1413 - 1417

Publisher

American Physiological Society

Location

Bethesda, Md.

ISSN

8750-7587

eISSN

1522-1601

Language

eng

Publication classification

C1.1 Refereed article in a scholarly journal

Copyright notice

1998, American Physiological Society