Pyruvate and hepatic pyruvate dehydrogenase levels in rat strains
sensitive and resistant to dietary obesity.
Nagase, H., G. A. Bray, and D. A. York.
Pennington Biomedical Research Center, 6400 Perkins Road, Baton
Rouge, LA 70808
APStracts 2:0271R, 1995.
This study compared the effects of exogenous pyruvate and lactate on
the serum levels of pyruvate, lactate, glucose, alanine and insulin
as well as the activity of hepatic pyruvate dehydrogenase (PDH) in
strains of rat that were either sensitive(Osborne-Mendel - OM) or
resistant (S5B/Pl) to high-fat dietary-induced obesity. Serum
pyruvate and lactate were significantly higher and glucose lower in
ad libitum fed OM rats, but these differences disappeared after an 18
hr fast. The increase in pyruvate and lactate after exogenous
pyruvate administration was significantly greater in S5B/Pl rats than
OM rats. There were no differences in serum alanine with strain or
diet. The total PDH activity was similar across strains and diets but
the proportion of PDH in its activated form (PDHa) was decreased in
ad lib fed S5B/Pl rats. Pyruvate injection increased insulin and
hepatic PDHa activity in OM rats fed both high fat and low fat diets,
but these responses were greatly attenuated or absent in S5B/Pl rats.
The data are consistent with the hypothesis that modulation of
carbohydrate oxidation by PDH may be related to susceptibility to
obesity when rats are fed a high fat diet.
Received 14 June 1995; accepted in final form 26 September 1995.
APS Manuscript Number R359-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 14 November 95