Expression of the Na(+)/H(+) exchanger isoform NHE1 in rat skeletal muscle and effect of training.
The expression of the Na(+)/H(+) exchanger isoform NHE1 was quantified in homogenates of various rat skeletal muscles by means of immunoblotting, and the effect of 3 weeks of treadmill training on NHE1 expression was determined in a red (oxidative) as well as a white (glycolytic)-muscle preparation. The NHE1 antibodies recognized a glycosylated protein at 101-111 kDa. There was a positive correlation between the NHE1 expression in the muscle and percent type IIB fibres and percent type IID/X fibres, whereas the NHE1 expressions were negatively correlated to percent type I fibres and percent type I + IIA fibres. Thus the highest NHE1 expression was evident in the most glycolytic fibres. Treadmill training increased (P < 0.05) the NHE1 content by 29 and 36% in oxidative and glycolytic fibres, respectively, suggesting that training enhanced the NHE1 content of all muscle-fibre types. Therefore training may improve the capacity for pH regulation in skeletal muscle.
Juel
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Copenhagen Muscle Research Centre, August Krogh Institute, University of Copenhagen, Denmark.
D000818:Animals; D018485:Muscle Fibers, Skeletal / Q000378:metabolism*; D005082:Physical Exertion / Q000502:physiology*; D020033:Protein Isoforms / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism*
D020033:Protein Isoforms; D017923:Sodium-Hydrogen Exchangers; C069139:growth factor-activatable Na-H exchanger NHE-1