Training intensity-dependent and tissue-specific increases in lactate uptake and MCT-1

Bonen. Training intensity-dependent and tissue-specific in-creases in lactate uptake and MCT-1 in heart and muscle. J. Appl. Physiol. 84(3): 987–994, 1998.—We investigated the effects of 3 wk of moderate- (21 m/min, 8 % grade) and high-intensity treadmill training (31 m/min, 15 % grade) on 1) monocarboxylate transporter 1 (MCT-1) content in rat hind-limb muscles and the heart and 2) lactate uptake in isolated soleus (Sol) muscles and perfused hearts. In the moderately trained group MCT-1 was not increased in any of the muscles [Sol, extensor digitorum longus (EDL), and red (RG) and white gastrocnemius (WG)] (P. 0.05). Similarly, lactate uptake in Sol strips was also not increased (P. 0.05). In contrast, in the heart, MCT-1 (136%, P, 0.05) and lactate uptake (172%, P, 0.05) were increased with moderate training. In the highly trained group, MCT-1 (170%, P