The relationship of the blood pyruvic acid level to deficiency states in infancy and childhood.

Thiamin, acting in the form of its phosphoric ester co-carboxylase, is an enzyme necessary for the complete metabolism of glucose. In its absence glucose is broken down as far as pyruvic acid, which then accumulates until vitamin B1 is supplied. Peters and Thompson (1934) and Peters (1936) demonstrated that the respiration of avitaminotic pigeon brain was reduced as compared with that of normal birds when either glucose, lactic or pyruvic acid was used as a substrate. The addition of crystalline vitamin B1 raised the respiration to normal. It was shown that the vitamin acted on a three-carbon compound which was pyruvic acid. Thompson and Johnson (1935) found a raised pyruvic acid, measured as 'Bisulphite Binding Substance' (which includes all compounds with carbonyl groups), in the blood of avitaminotic animals. Shortly afterwards Platt and Lu (1936) reported its presence in the blood in cases of acute oriental beri-beri. The establishment of a direct method by Peters and Thompson (1934) and Platt and Lu (1936) for the estimation of pyruvic acid has enabled this stage of carbohydrate metabolism to be extensively studied. Figures for the normal resting blood pyruvic acid in man have been determined by several investigators (Table 1), who all give mean values of less than 1-0 mg. per 100 c.cm. of blood.