Effect of high-intensity exercise training on lactate/H1 transport capacity in human skeletal muscle

Pilegaard, Henriette, Kristian Domino, Thomas Noland, Carsten Juel, Ylva Hellsten, Andrew P. Halestrap, and Jens Bangsbo. Effect of high-intensity exercise training on lactate/H1 transport capacity in human skeletal muscle. Am. J. Physiol. 276 (Endocrinol. Metab. 39): E255– E261, 1999.—The present study examined the effect of highintensity exercise training on muscle sarcolemmal lactate/H1 transport and the monocarboxylate transporters (MCT1 and MCT4) as well as lactate and H1 release during intense exercise in humans. One-legged knee-extensor exercise training was performed for 8 wk, and biopsies were obtained from untrained and trained vastus lateralis muscle. The rate of lactate/H1 transport determined in sarcolemmal giant vesicles was 12% higher (P , 0.05) in the trained than in untrained muscle (n 5 7). The content of MCT1 and MCT4 protein was also higher (76 and 32%, respectively; n 5 4) in trained muscle. Release of lactate and H1 from the quadriceps muscle at the end of intense exhaustive knee-extensor exercise was similar in the trained and untrained leg, although the estimated muscle intracellular-to-interstitial gradients of lactate and H1 were lower (P , 0.05) in the trained than in the untrained muscle. The present data show that intense exercise training can increase lactate/H1 transport capacity in human skeletal muscle as well as improve the ability of the muscle to release lactate and H1 during contractions.