AJP - Regulatory, Integrative and Comparative Physiology, Vol 255, Issue 4 547-R556, Copyright © 1988 by American Physiological Society

ARTICLES

Central and peripheral adrenoceptors affect glucose, free fatty acids, and insulin in exercising rats

A. J. Scheurink, A. B. Steffens and L. Benthem
Department of Animal Physiology, State University of Groningen, Haren, The Netherlands.

The effects of intravenously and intrahypothalamically administered alpha- and beta-adrenoceptor antagonists on exercise-induced alterations in blood glucose, plasma free fatty acids (FFA), and insulin were investigated in rats. Exercise consisted of strenuous swimming against a counter current for 15 min. Before, during, and after swimming, blood samples were withdrawn through a permanent heart catheter. Intravenous administration of the alpha-blocker phentolamine led to a reduction in glucose and a substantial increase in insulin levels. Infusion of phentolamine through permanent bilateral cannulas into either the ventromedial or lateral area of the hypothalamus (VMH and LHA, respectively) completely prevented the increase in glucose while the decline in insulin was unaffected. Infusion of phentolamine into the VMH caused much higher plasma FFA levels than in controls. The beta-blocker timolol given intravenously caused a delayed increase in glucose and prevented the increase in FFA. Infusion of timolol into either VMH or LHA caused a delay in the increase in both glucose and FFA. The results suggest that 1) both peripheral and hypothalamic adrenoceptors are involved in energy metabolism during exercise and 2) FFA, glucose, and insulin concentrations in blood are independently regulated by VMH and LHA.

This article has been cited by other articles:

				T. Shibakusa, W. Mizunoya, Y. Okabe, S. Matsumura, Y. Iwaki, A. Okuno, K. Shibata, K. Inoue, and T. Fushiki Transforming growth factor-beta in the brain is activated by exercise and increases mobilization of fat-related energy substrates in rats Am J Physiol Regulatory Integrative Comp Physiol, May 1, 2007; 292(5): R1851 - R1861. [Abstract] [Full Text] [PDF]

				J. L. Beverly, M. G. De Vries, S. D. Bouman, and L. M. Arseneau Noradrenergic and GABAergic systems in the medial hypothalamus are activated during hypoglycemia Am J Physiol Regulatory Integrative Comp Physiol, February 1, 2001; 280(2): R563 - R569. [Abstract] [Full Text] [PDF]

				A. Takahashi, E. Kishi, H. Ishimaru, Y. Ikarashi, and Y. Maruyama Stimulation of rat hypothalamus by microdialysis with K+: increase of ACh release elevates plasma glucose Am J Physiol Regulatory Integrative Comp Physiol, November 1, 1998; 275(5): R1647 - R1653. [Abstract] [Full Text] [PDF]

				L. Mantha and Y. Deshaies beta -Adrenergic modulation of triglyceridemia under increased energy expenditure Am J Physiol Regulatory Integrative Comp Physiol, June 1, 1998; 274(6): R1769 - R1776. [Abstract] [Full Text] [PDF]