Effect of dichloroacetate on plasma lactic acid in exercising dogs

Abstract

Dichloroacetate sodium (DCA) reduced circulating levels of lactic acid (LA) under a variety of experimental and clinical conditions. The effect of DCA on the lactacidemia of exercise in treadmill-exercised dogs was examined. One group of animals (n = 8) was tested at light, moderate and heavy exercise work loads. Plasma LA, 19 .+-. 2 mg/dl at rest, increased to 26 .+-. 4, 38 .+-. 5 and 52 .+-. 6 mg/dl during the 3 workloads, respectively. In the same animals, when identical treadmill tests were conducted after DCA (100 mg/kg, i.v.), the rise in LA was significantly attenuated. Lactic acid values were 11 .+-. 2 mg/dl at rest after DCA and 15 .+-. 2, 20 .+-. 4 and 23 .+-. 3 mg/dl for the light, moderate and heavy workloads, respectively. Another group of dogs (n = 6) performed prolonged moderate exercise. Under untreated conditions, LA increased from 24 .+-. 1 mg/dl at rest, to 41 .+-. 6 mg/dl at 10 min and 50 .+-. 5 mg/dl at 50 min. During repeat tests DCA was given at 12 min when LA was 30 .+-. 6 mg/dl. At 50 min LA was 18 .+-. 3 mg/dl or 60% lower than that observed during the untreated run. Because DCA increased pyruvate dehydrogenase enzyme activity, this enzyme may be an important factor in LA metabolism during exercise.