Induction of heme oxygenase-1 (hsp 32) mrna in skeletal muscle
following contractions.
Essig, David A., Darrell R. Borger, and David A. Jackson.
Department of Exercise Science, Laboratory of Exercise Molecular
Biology, University of South Carolina, Columbia, SC
APStracts 3:0262C, 1996.
The capacity of pre-existing antioxidant pathways to handle oxidative
stress during exercise may be complemented by the synthesis of
inducible heat stress proteins (HSPs). Our purpose was to determine
if the amount of mRNA for HSP 32, a major oxidative stress protein,
was increased in muscle following repetitive contractions. RT-PCR
analysis showed that HSP 32 mRNA (normalized to [alpha]-actin mRNA)
was increased 7- and 4-fold (p < 0.05) immediately following 1 h
of exhaustive running or 3h of muscle contractions (10 Hz nerve
stimulation), respectively. Northern blot analysis revealed that HSP
70 mRNAs were 3.5- to 15.5-fold above control value (p<0.05)
while the content of another oxidative stress protein mRNA (MSP 23)
was unchanged 0h after contractions. The relative increase in HSP 32
mRNA was found to be dependent upon active tension generation;
passive tension did not increase the HSP 32/actin mRNA ratio.
Increases in HSP 32 mRNA may underlie an inducible antioxidant
pathway in muscle responsive to metabolic stresses associated with
repeated muscle contractions.
Received 14 February 1996; accepted in final form 28 June 1996.
APS Manuscript Number C83-6.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 21 August 1996