METABOLISM OF GLUCURONIC ACID IN FATIGUE DUE TO PHYSICAL EXERCISE

Abstract

Concerning the cause of fatigue, there have been many assumptions on the basis of energy accumulation of substances inducing fatigue. There have been a lot of studies (1, 2) on piling up of the so-called fatigue substances. In the book edited by Katsunuma and Asahina (3), it was reported that the so-called fatigue substances were found by Ueda, Weichart, Pieron, Knipping, Denisenko, Asahina, Ozawa, Vorobew, Pravdic and Neminsky. They assumed that these substances were the metabolites from degraded protein. As mentioned above, there are many reports concerning the cause of fatigue, but we cannot but conceive some questions for their chemical nature. In our investigation on the appearance of fatigue due to physical exercise, the fact that a certain kind of metabolic substance was produced and accumulated from the energy source consumed by the physical exercise. Our investigation was begun to study the relationship between the change of this metabolic product and the change of glucuronic acid metabolism due to physical exercise in the body. The first experiment was done by Tamura in participation in Abe's studies (4, 5) on agents relieving fatigue and increasing efficiency, in 1942. The summary of this study is as follows: the rat was made to run as long as possible on the rotating belt and the time being almost impossible to run was adopted as running time. The running was repeated three times after a short rest. This running test revealed that the central stimulants such as caffeine and amphetamine prolonged only the 1st running time, while glucose and glucuronic acid prolonged all of the 1st, the 2nd and the 3rd running time. In other words, the reducing agents such as glucose and glucuronic acid much more prevented the appearance of fatigue than the central stimulants.