N. Eydoux et al., Training does not protect against exhaustive exercise-induced lactate transport capacity alterations, AM J P-ENDO, 278(6), 2000, pp. E1045-E1052
Citations number
40
Categorie Soggetti
Endocrinology, Nutrition & Metabolism
Journal title
AMERICAN JOURNAL OF PHYSIOLOGY-ENDOCRINOLOGY AND METABOLISM
The effects of endurance training on lactate transport capacity remain cont
roversial. This study examined whether endurance training 1) alters lactate
transport capacity, 2) can protect against exhaustive exercise-induced lac
tate transport alteration, and 3) can modify heart and oxidative muscle mon
ocarboxylate transporter 1 (MCT1) content. Forty male Wistar rats were divi
ded into control (C), trained (T), exhaustively exercised (E), and trained
and exercised (TE) groups. Rats in the T and TE groups ran on a treadmill (
1 h/day, 5 days/wk at 25 m/min, 10% incline) for 5 wk; C and E were familia
rized with the exercise task for 5 min/day. Before being killed, E and TE r
ats underwent exhaustive exercise (25 m/min, 10% grade), which lasted 80 an
d 204 min, respectively (P < 0.05). Although lactate transport measurements
(zero-trans) did not differ between groups C and T, both E and TE groups p
resented an apparent loss of protein saturation properties. In the trained
groups, MCT1 content increased in soleus (+28% for T and +26% for TE; P < 0
.05) and heart muscle (+36% for T and +33% for TE; P < 0.05). Moreover, des
pite the metabolic adaptations typically observed after endurance training,
we also noted increased lipid peroxidation byproducts after exhaustive exe
rcise. We concluded that 1) endurance training does not alter lactate trans
port capacity, 2) exhaustive exercise-induced lactate transport alteration
is not prevented by training despite increased MCT1 content, and 3) exercis
e-induced oxidative stress may enhance the passive diffusion responsible fo
r the apparent loss of saturation properties, possibly masking lactate tran
sport regulation.