Resistance training upregulates skeletal muscle Na+, K+-ATPase content, with elevations in both α1 and α2, but not β isoforms

Purpose The Na + , K + -ATPase (NKA) is important in regulating trans-membrane ion gradients, cellular excitability and muscle function. We investigated the effects of resistance training in healthy young adults on the adaptability of NKA content and of the specific α and β isoforms in human skeletal muscle. Methods Twenty-one healthy young males (22.9 ± 4.6 year; 1.80 ± 0.70 m, 85.1 ± 17.8 kg, mean ± SD) underwent 7 weeks of resistance training, training three times per week (RT, n = 16) or control (CON, n = 5). The training program was effective with a 39% gain in leg press muscle strength ( p = 0.001). A resting vastus lateralis muscle biopsy was taken before and following RT or CON and assayed for NKA content ([ 3 H]ouabain binding site content) and NKA isoform (α 1 , α 2 , β 1, β 2 ) abundances. Results After RT, each of NKA content (12%, 311 ± 76 vs 349 ± 76 pmol g wet weight −1 , p = 0.01), NKA α 1 (32%, p = 0.01) and α 2 (10%, p