Intense exercise up-regulates Na+, K+ -ATPase isoform mRNA, but not protein expression in human skeletal muscle


Autoria(s): Murphy, K.T.; Snow, Rod; Petersen, A.; Murphy, R.; Mollica, J.; Lee, J.; Garnham, Andrew; Aughey, R.; Leppik, J.; Medved, I.; Cameron-Smith, David; McKenna, M.
Data(s)

01/01/2004

Resumo

Characterization of expression of, and consequently also the acute exercise effects on, Na+,K+-ATPase isoforms in human skeletal muscle remains incomplete and was therefore investigated. Fifteen healthy subjects (eight males, seven females) performed fatiguing, knee extensor exercise at 40% of their maximal work output per contraction. A vastus lateralis muscle biopsy was taken at rest, fatigue and 3 and 24 h postexercise, and analysed for Na+,K+-ATPase 1, 2, 3, ß1, ß2 and ß3 mRNA and crude homogenate protein expression, using Real-Time RT-PCR and immunoblotting, respectively. Each individual expressed gene transcripts and protein bands for each Na+,K+-ATPase isoform. Each isoform was also expressed in a primary human skeletal muscle cell culture. Intense exercise (352 ± 69 s; mean ±S.E.M.) immediately increased 3 and ß2 mRNA by 2.4- and 1.7-fold, respectively (P < 0.05), whilst 1 and 2 mRNA were increased by 2.5- and 3.5-fold at 24 h and 3 h postexercise, respectively (P < 0.05). No significant change occurred for ß1 and ß3 mRNA, reflecting variable time-dependent responses. When the average postexercise value was contrasted to rest, mRNA increased for 1, 2, 3, ß1, ß2 and ß3 isoforms, by 1.4-, 2.2-, 1.4-, 1.1-, 1.0- and 1.0-fold, respectively (P < 0.05). However, exercise did not alter the protein abundance of the 1–3 and ß1–ß3 isoforms. Thus, human skeletal muscle expresses each of the Na+,K+-ATPase 1, 2, 3, ß1, ß2 and ß3 isoforms, evidenced at both transcription and protein levels. Whilst brief exercise increased Na+,K+-ATPase isoform mRNA expression, there was no effect on isoform protein expression, suggesting that the exercise challenge was insufficient for muscle Na+,K+-ATPase up-regulation. <br /><br />

Identificador

http://hdl.handle.net/10536/DRO/DU:30008683

Idioma(s)

eng

Publicador

Cambridge University Press

Relação

http://dro.deakin.edu.au/eserv/DU:30008683/n20040299.pdf

http://dx.doi.org/10.1113/jphysiol.2003.054981

Direitos

2004, The Physiological Society

Tipo

Journal Article