TY - JOUR

T1 - Kinetics of lactate and pyruvate transport in cultured rat myotubes

AU - von Grumbckow, Lena

AU - Elsner, Peter

AU - Hellsten, Ylva

AU - Quistorff, Bjørn

AU - Juel, Carsten

N1 - Keywords: Animals; Biological Transport; Carrier Proteins; Cell Differentiation; Cells, Cultured; Creatine Kinase; Fluoresceins; Fluorescent Dyes; Kinetics; Lactic Acid; Monocarboxylic Acid Transporters; Muscle, Skeletal; Protein Isoforms; Pyruvic Acid; Rats; Rats, Wistar

PY - 1999

Y1 - 1999

N2 - Skeletal muscle transport of lactate and pyruvate was studied in primary cultures of rat myotubes, applying the pH-sensitive fluorescent indicator 2', 7'-bis(carboxyethyl)-5(6)-carboxyfluorescein. The initial rate of decrease in intracellular pH (pHi) upon lactate or pyruvate incubation was used to determine total transport (carrier mediated and diffusion). Both lactate and pyruvate transport could be inhibited by a combination of 0.5 mM 4,4'-diisothiocyanostilbene-2, 2'-disulfonic acid, 5 mM mersalyl and 10 mM alpha-cyano-4-hydroxycinnamate. The kinetic parameters, Km and Vmax, for carrier-mediated transport of lactate were 9.9+/-1.1 mM and 0. 69+/-0.02 mmol l-1 s-1, respectively. For pyruvate, Km and Vmax were 4.4+/-1.3 mM and 0.30+/-0.05 mmol l-1 s-1, respectively. The diffusion component of the total transport was 0.0040+/-0.0005[S] (n=4) and 0.0048+/-0.0003[S] (n=4) for lactate and pyruvate, respectively. Furthermore, it was observed that the two monocarboxylate transporter isoforms present in mature skeletal muscles, MCT1 and MCT4 (formerly called MCT3 (M.C. Wilson, V.N. Jackson, C. Heddle, N.T. Price, H. Pilegaard, C. Juel, A. Bonen, I. Montgomery, O.F. Hutter, A.P. Halestrap, Lactic acid efflux from white skeletal muscle is catalyzed by the monocarboxylate transporter isoform MCT3, J. Biol. Chem. 273 (1998) 15920-15926)), were also expressed in primary culture of myotubes.

AB - Skeletal muscle transport of lactate and pyruvate was studied in primary cultures of rat myotubes, applying the pH-sensitive fluorescent indicator 2', 7'-bis(carboxyethyl)-5(6)-carboxyfluorescein. The initial rate of decrease in intracellular pH (pHi) upon lactate or pyruvate incubation was used to determine total transport (carrier mediated and diffusion). Both lactate and pyruvate transport could be inhibited by a combination of 0.5 mM 4,4'-diisothiocyanostilbene-2, 2'-disulfonic acid, 5 mM mersalyl and 10 mM alpha-cyano-4-hydroxycinnamate. The kinetic parameters, Km and Vmax, for carrier-mediated transport of lactate were 9.9+/-1.1 mM and 0. 69+/-0.02 mmol l-1 s-1, respectively. For pyruvate, Km and Vmax were 4.4+/-1.3 mM and 0.30+/-0.05 mmol l-1 s-1, respectively. The diffusion component of the total transport was 0.0040+/-0.0005[S] (n=4) and 0.0048+/-0.0003[S] (n=4) for lactate and pyruvate, respectively. Furthermore, it was observed that the two monocarboxylate transporter isoforms present in mature skeletal muscles, MCT1 and MCT4 (formerly called MCT3 (M.C. Wilson, V.N. Jackson, C. Heddle, N.T. Price, H. Pilegaard, C. Juel, A. Bonen, I. Montgomery, O.F. Hutter, A.P. Halestrap, Lactic acid efflux from white skeletal muscle is catalyzed by the monocarboxylate transporter isoform MCT3, J. Biol. Chem. 273 (1998) 15920-15926)), were also expressed in primary culture of myotubes.

M3 - Journal article

C2 - 10082802

VL - 1417

SP - 267

EP - 275

JO - B B A - General Subjects

JF - B B A - General Subjects

SN - 0304-4165

IS - 2

ER -