Effect of epinephrine on net lactate uptake by contracting skeletal muscle

J Appl Physiol (1985). 2001 Dec;91(6):2635-41. doi: 10.1152/jappl.2001.91.6.2635.

Abstract

The purpose of this study was to determine the effect of epinephrine on net lactate (La(-)) uptake at constant elevated blood La(-) concentration and steady level metabolic rate (O(2) uptake) in the canine gastrocnemius-plantaris muscle in situ. Infusion of La(-)/lactic acid (pH 3.5) established a mean arterial blood La(-) concentration of ~10 mM while normal blood-gas and pH status were maintained as the gastrocnemius-plantaris was stimulated with tetanic trains at a rate of one contraction every 4 s. After steady-state control measures, epinephrine was infused for 35 min at rates that produced a high physiological concentration with (Pro; n = 6) and without (Epi; n = 6) beta-adrenergic-receptor blockade via propranolol. Net La(-) uptake values during the control conditions were not significantly different between trials (Epi: 0.756 +/- 0.043; Pro: 0.703 +/- 0.061 mmol. kg(-1). min(-1)). Steady level O(2) uptake averaged approximately 69.5 ml. kg(-1). min(-1) for both control conditions and did not significantly change over the course of the experiments in either set of trials. Epi experiments resulted in a significantly reduced net La(-) uptake (0.346 +/- 0.088 mmol. kg(-1). min(-1) after 5 min of infusion) compared with control value at all sample times measured. However, net La(-) uptake was not significantly different from control at any time during Pro (0.609 +/- 0.052 mmol. kg(-1). min(-1) after 5 min of infusion). When the change from the respective control values for net La(-) uptake was compared across time for both series of experiments, Epi resulted in a significantly greater change from control than did Pro. This study suggests that epinephrine can have a profound effect on net La(-) uptake by contracting muscle and that these effects are elicited through beta-adrenergic-receptor stimulation.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adrenergic alpha-Agonists / pharmacology*
  • Adrenergic beta-Antagonists / pharmacology
  • Animals
  • Dogs
  • Electric Stimulation
  • Epinephrine / pharmacology*
  • Female
  • Homeostasis
  • Lactic Acid / blood
  • Lactic Acid / pharmacokinetics*
  • Male
  • Muscle Contraction / physiology*
  • Muscle, Skeletal / drug effects
  • Muscle, Skeletal / physiology*
  • Oxygen Consumption
  • Propranolol / pharmacology

Substances

  • Adrenergic alpha-Agonists
  • Adrenergic beta-Antagonists
  • Lactic Acid
  • Propranolol
  • Epinephrine