Studies on the metabolism of pyruvic acid in normal and vitamin B1-deficient states

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Abstract
Light muscular work by vit. Bi-deficient human subjects is followed by an increase of blood pyruvate as measured by the 2,4-dinitrophenylhydrazone method. The rise of pyruvate may be maintained or still further increased at the end of half an hour''s rest after the exercise. After the intraven. adm. of pure vit. B1, light exercise may or may,not be followed by an immediate increase of blood pyruvate; following half an hour''s rest after the exercise "resting levels" are found. This restoration of the level may be accounted for on the grounds that less pyruvate has been formed in exercise or that it has been more rapidly removed. When the changes of blood pyruvate are inconsiderable, marked increase, accompanied by clinical manifestations resembling those of fulminating beri-beri, may follow heavier work. Still heavier work may be well tolerated by subjects adequately supplied with vit. B1, and be insufficient appreciably to raise the blood pyruvate. Values for blood pyruvate as high as those found in fulminating beri-beri may be attained after exercise of deficient subjects. Similar high values are reached by normal subjects when exercised to exhaustion. During rest after exercise, however, initial values are restored to normal subjects in less than 1 hr. In vit. Bi-deficient subjects there is delayed recovery after high values following exercise. In an expt. in which high levels of blood pyruvate were produced in a deficient subject it was found that maximal values were not attained until some time after the completion of the exercise. Bisulphite-binding substances (calculated as pyruvic acid) are increased when blood pyruvate is markedly increased, but to an extent greater than can be accounted for by the increase of pyruvic acid as estimated by the hydrazone method. "Pyruvic acid" is excreted in increased amts. after exercise. Circulatory changes accompanying accumulation of pyruvate occur after exercise of a deficient subject. Excessive muscular work is discussed as one of a number of factors which may be responsible for the development of vit. B1 deficiency. Exercise of the whole body combined with measurements of blood pyruvate may be used as a method for revealing latent vit. B1 deficiency.