Malleability of human skeletal muscle Na(+)-K(+)-ATPase pump with short-term training.
To investigate the hypothesis that short-term submaximal training would result in changes in Na(+)-K(+)-ATPase content, activity, and isoform distribution in skeletal muscle, seven healthy, untrained men [peak aerobic power (peak oxygen consumption; Vo(2 peak)) = 45.6 ml x kg(-1) x min(-1) (SE 5.4)] cycled for 2 h/day at 60-65% Vo(2 peak) for 6 days. Muscle tissue, sampled from the vastus lateralis before training (0 days) and after 3 and 6 days of training and analyzed for Na(+)-K(+)-ATPase content, as assessed by the vanadate facilitated [(3)H]ouabain-binding technique, was increased (P < 0.05) at 3 days (294 +/- 8.6 pmol/g wet wt) and 6 days (308 +/- 15 pmol/g wet wt) of training compared with 0 days (272 +/- 9.7 pmol/g wet wt). Maximal Na(+)-K(+)-ATPase activity as evaluated by the 3-O-methylfluorescein phosphatase assay was increased (P < 0.05) by 6 days (53.4 +/- 5.9 nmol x h(-1) x mg protein(-1)) but not by 3 days (35.9 +/- 4.5 nmol x h(-1) x mg protein(-1)) compared with 0 days (37.8 +/- 3.7 nmol x h(-1) x mg protein(-1)) of training. Relative isoform distribution, measured by Western blot techniques, indicated increases (P < 0.05) in alpha(2)-content by 3 days and beta(1)-content by 6 days of training. These results indicate that prolonged aerobic exercise represents a potent stimulus for the rapid adaptation of Na(+)-K(+)-ATPase content, isoform, and activity characteristics.
Green
H J
HJ
Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada N2L 3G1. green@healthy.uwaterloo.ca
Barr
D J
DJ
Fowles
J R
JR
Sandiford
S D
SD
Ouyang
J
J
D000328:Adult; D015308:Anaerobic Threshold / Q000502:physiology; D001642:Bicycling / Q000502:physiology; D015444:Exercise / Q000502:physiology; D005452:Fluoresceins; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism; D008163:Luminescent Measurements; D008297:Male; D018482:Muscle, Skeletal / Q000201:enzymology* / Q000502:physiology*; D010042:Ouabain / Q000378:metabolism; D010100:Oxygen / Q000097:blood; D010809:Physical Fitness / Q000502:physiology*; D000254:Sodium-Potassium-Exchanging ATPase / Q000096:biosynthesis / Q000378:metabolism*
C032079:3-O-methylfluorescein phosphate; D005452:Fluoresceins; D007527:Isoenzymes; D010042:Ouabain; D000254:Sodium-Potassium-Exchanging ATPase; D010100:Oxygen