Gene expression of sarcoplasmic reticulum calcium atpase and
mitochondrial cytochrome oxidase are increased in the hearts of
exercised trained old rats.
Tate, Charlotte A., Thorunn Helgason, Michael F. Hyek, R. Perley
McBride, Minhui Chen, Michelle A. Richardson, and George E. Taffet.
Department of Pharmacological & Pharmaceutical Sciences,
University of Houston, Houston, Texas 77204-5515; Sections of
Cardiovascular Sciences and Geriatrics, Department of Medicine,
Baylor College of Medicine, Houston, Texas 77030
APStracts 2:0527H, 1995.
Aging of rats results in slower activities of calcium transport by
cardiac calcium ATPase of the sarcoplasmic reticulum (SR) and
mitochondrial cytochrome oxidase (COX). These enzyme activities are
faster after exercise training of previously sedentary old rats. Our
purpose was to determine if the expression of the genes encoding SR
calcium ATPase (SERCA2a) or COX is altered by exercise training. Old
male F344 rats (24-months) were assigned to SO (sedentary old) or EO
(exercised old) and compared to younger sedentary rats 12-months of
age (SM). EO rats were trained on a treadmill for 8-10 weeks. SERCA2a
and COX mRNAs were lower (p<0.05) in SO compared to SM and EO
while GAPDH and cardiac [alpha]-actin mRNAs were similar across
groups. The immunoreactive protein contents of cardiac calcium
ATPase, cytochrome c, sarcomeric actin, and GAPDH followed the
changes, when observed, in mRNA contents. Thus, pretranslational
mechanisms may be modified in some genes during aging and exercise
training of previously sedentary old rats.
Received 14 February 1995; accepted in final form 9 November
1995.
APS Manuscript Number H136-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 8 December 95