Kja. Mccullagh et al., ROLE OF THE LACTATE TRANSPORTER (MCT1) IN SKELETAL-MUSCLES, American journal of physiology: endocrinology and metabolism, 34(1), 1996, pp. 143-150
We used an antibody, constructed against the monocarboxylate transport
er 1 (MCT1) protein (L. Carpenter, R. C. Poole, and A. P. Halestrap. B
iochim. Biophys. Acta 1279: 157-165, 1996), to study the expression an
d 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 (%slow-twitch oxidative + %fast-twitch oxidative glycol
ytic) of skeletal muscles (r = 0.91). MCT1 was highly related to lacta
te uptake in skeletal muscles (r = 0.90). Total lactate dehydrogenase
(LDH) activity, an index of glycolysis, was negatively correlated with
MCT1 in rat muscles (r = -0.80). MCT1 was also strongly correlated wi
th the heart-type forms of LDH (LDH-1 vs. MCT1, r = 0.83; LDH-2 vs. MC
T1, r = 0.89). There was no relationship between MCT1 and the muscle f
orm 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 that favor the uptake of L-lac
tate into the muscle cell for oxidative metabolism, and MCT1 may be co
ordinately expressed with the heart forms of LDH and enzymes of oxidat
ive metabolism.