AJP - Endocrinology and Metabolism, Vol 265, Issue 5 E777-E782, Copyright © 1993 by American Physiological Society

ARTICLES

Differential effect of metabolic fuels on the energy state and Na(+)-K(+)-ATPase in isolated cerebral microvessels

I. Sussman, V. Schultz, S. Gupta, C. Grady, N. B. Ruderman and K. Tornheim
Evans Department of Medicine, Boston University School of Medicine, Massachusetts 02118.

Isolated bovine cerebral microvessels (ICMV) were incubated with different metabolic fuels to determine their ability to support microvessel Na(+)-K(+)-ATPase (quantitated as ouabain-sensitive 86Rb+ uptake) and the ATP/ADP ratio. In comparison with ICMV incubated with glucose, Na(+)-K(+)-ATPase activity was reduced by 55% after a 3-h incubation in fuel-free medium and by 30-40% after incubation with beta-hydroxybutyrate, acetoacetate, or glutamate. However, Na(+)-K(+)-ATPase activity was not significantly decreased in ICMV incubated with pyruvate or oleate plus carnitine. In contrast, only glucose was able to maintain the ATP/ADP ratio. To evaluate the effect of endogenous fatty acid metabolism on these parameters, ICMV were incubated with bromostearate, an inhibitor of fatty acid oxidation. Bromostearate decreased both Na(+)-K(+)-ATPase activity and the ATP/ADP ratio, even in the presence of glucose. These results indicate that the varying effects of different fuels on Na(+)-K(+)-ATPase in ICMV cannot be explained solely by their effects on the ATP/ADP ratio or on glycolytic ATP generation. They suggest that other fuel-modulated factors play a key role in regulating this enzyme.

This article has been cited by other articles:

				J. R. Sowers Insulin and Insulin-Like Growth Factor in Normal and Pathological Cardiovascular Physiology Hypertension, March 1, 1997; 29(3): 691 - 699. [Full Text]

				Z. Dagher, N. Ruderman, K. Tornheim, and Y. Ido Acute Regulation of Fatty Acid Oxidation and AMP-Activated Protein Kinase in Human Umbilical Vein Endothelial Cells Circ. Res., June 22, 2001; 88(12): 1276 - 1282. [Abstract] [Full Text] [PDF]