Dichloroacetate: effects on exercise endurance in untrained rats.

The effect of dichloroacetate (DCA), an activator of pyruvate dehydrogenase, on the performance of fed, untrained rats was evaluated while swimming for different durations. DCA-treated rats were able to swim almost 40% longer than controls (354 plus or minus 18 sec, p less than .001). This was associated with lower levels of blood and muscle lactate at rest and after 210 and 240 sec of swimming. At exhaustion, blood lactate was the same in the two groups even though the DCA rats had worked for an additional 99 sec (16.9 plus or minus 1.2 versus 15.8 plus or minus 1.2 mM/L NS). Pretreatment with DCA did not alter the usual exercise-induced decreases in muscle ATP and creatine phosphate or liver glycogen. After 210 sec of exercise, plasma FFA and blood glucose and acetoacetate were also the same in the two groups; however, beta-hydroxybutyrate was somewhat higher, and there was a small but significant sparing of muscle glycogen in te DCA group. The data indicate that DCA enhances the ability of rats to exercise at near maximal work loads. They are consistent with the notion that improved endurance is a consequence of a decreased rate of lactate accumulation; however, the possibility that it is secondary to some other action of DCA cannot be excluded.