The role of the lactate transporter (mct1) in skeletal muscles.
McCullagh, Karl J. A., Robert C. Poole, Andrew P. Halestrap, Moira
O'brien, Arend Bonen.
Department of Anatomy and Physiology, Trinity College Dublin,
Dublin 2, Ireland, Department of Biochemistry, University of Bristol,
Bristol, U.K., Department of Kinesiology, University of Waterloo,
Waterloo, Ontario, N2L 3G1
APStracts 3:0050E, 1996.
We used an antibody, constructed against the monocarboxylate
transporter 1 (MCT1) protein (Carpenter et al. 1995), to study the
expression and role of MCT1 in rat skeletal muscles. MCT1 was higher
in red than in white muscles (P<0.05) and was highly correlated
with the oxidative fiber content (%SO+%FOG) of skeletal muscles (r =
0.91). MCT1 was highly related to lactate uptake in skeletal muscles
(r = 0.90). Total LDH activity,an index of glycolysis, was negatively
correlated with MCT1 in rat muscles (r = - 0.80). MCT1 was also
strongly correlated with the Heart-type forms of LDH (LDH-1 vs MCT1,
r = 0.83; LDH-2 vs MCT1, r = 0.89). There was no relationship Between
MCT1 and the muscle form of LDH (LDH-5 ) (P>0.05). MCT1 was
highly correlated with citrate synthase activity, a marker of the
oxidative capacity of muscle (r = 0.82). Therefore, MCT1 may have
kinetics which favour the uptake of L-lactate into the muscle cell
for oxidative metabolism, and MCT1 may be coordinately expressed with
the Heart- forms of LDH and enzymes of oxidative metabolism.
Received 21 November 1995; accepted in final form 20 February
1996.
APS Manuscript Number E551-5.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 20 March 96