Sympathoadrenal influence on glucose, FFA, and insulin levels in exercising rats

A.J.W. Scheurink, A.B. Steffens, H. Bouritius, G.H. Dreteler, R. Bruntink, R. Remie, J. Zaagsma

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Abstract

The effects of sympathoadrenal manipulations on the exercise-induced alterations in blood glucose, plasma free fatty acids (FFA), and insulin were investigated in intact and adrenodemedullated rats. Exercise consisted of strenuous swimming against a countercurrent for 15 min. Before, during, and after swimming, blood samples were taken through a permanent heart catheter. Adrenodemedullation (Adm) markedly reduced the exercise-induced increase in both glucose and FFA. This effect was counteracted by intravenous infusion of epinephrine (E, 20 ng/min). Intravenous infusion of 50 ng E/min into Adm rats caused an exaggerated increase in glucose. In two additional experiments 1) specific adrenoceptor agonists and antagonists were administered to exercising intact and Adm rats, and 2) E or norepinephrine (NE; 20 ng/min) was infused into intact resting rats. The results suggest that E from the adrenal medulla directly affects glucose and insulin but not FFA concentrations in the blood. NE released from peripheral sympathetic nerve endings probably acts in two different ways: as neurotransmitter on liver and pancreas and as a hormone on adipose tissue.
Original languageEnglish
Pages (from-to)R161-R168
JournalThe American Journal of Physiology - Regulatory, Integrative and Comparative Physiology
Volume256
Publication statusPublished - 1989

Keywords

  • adrenergic agonists and antagonists
  • adrenal medulla, sympathetic nerve endings
  • exercise

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