Glucose production during strenuous exercise in humans: Role of epinephrine

Kirsten Howlett, Mark Febbraio, Mark Hargreaves

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Abstract

The increase in hepatic glucose production (HGP) that occurs during intense exercise is accompanied by a simultaneous increase in epinephrine, which suggests that epinephrine may be important in regulating HGP. To further investigate this, six trained men were studied twice. The first trial [control (Con)] consisted of 20 min of cycling at 40 0± 1% peak oxygen uptake (V̇O(2 peak)) followed by 20 min at 80 ± 2% V̇O(2peak). During the second trial [epinephrine (Epi)], subjects exercised for 40 min at 41 ± 2% V̇O(2peak). Epinephrine was infused during the latter 20 min of exercise and resulted in plasma levels similar to those measured during intense exercise in Con. Glucose kinetics were measured using a primed, continuous infusion of [3-3H]glucose. HGP was similar at rest (Con, 11.0 ± 0.5 and Epi, 11.1 ± 0.5 μmol · kg-1 · min-1). In Con, HGP increased (P < 0.05) during exercise to 41.0 ± 5.2 μmol · kg-1 · min-1 at 40 min. In Epi, HGP was similar to Con during the first 20 min of exercise. Epinephrine infusion increased (P < 0.05) HGP to 24.0 ± 2.5 μmol · kg-1 · min-1 at 40 min, although this was less (P < 0.05) than the value in Con. The results suggest that epinephrine can increase HGP during exercise in trained men; however, epinephrine during intense exercise cannot fully account for the rise in HGP. Other glucoregulatory factors must contribute to the increase in HGP during intense exercise.

Original languageEnglish
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Volume276
Issue number6 39-6
Publication statusPublished - 1 Jun 1999
Externally publishedYes

Keywords

  • Catecholamines
  • Glucose kinetics
  • Liver

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