Lxxx. Blood Pyruvate in Vitamin B1 Deficiency

IN the course of recent work on the role of vitamin B, in the metabolism of brain, it was discovered [Peters and Sinclair, 1933] that lactate solutions in which avitaminous pigeon's brain cells had respired for 2 hours gave a positive nitroprusside reaction for pyruvic acid [Simon and Piaux, 1924]. This led to a quantitative investigation of the formation of pyruvic acid during the respiration of normal and avitaminous brain tissue in vitro [Peters and Thompson, 1934]. In the course of this work it was discovered that relatively large amounts of pyruvic acid appear during the respiration in lactate of the minced brain tissue from vitamin B,-deficient pigeons, whereas only a negligible amount (too little to be detected by the nitroprusside reaction) appears during the respiration under similar conditions of the brain tissue from normal pigeons. Further indirect evidence was thereby obtained in support of the recent Embden-Meyerhof scheme, which includes pyruvic acid as a normal intermediary in the metabolism of carbohydrate in the animal organism [see Embden et al., 1933; Meyerhof and Kiessling, 1933; Meyerhof, 1933]. But although it was shown that there was this marked difference in the rates of pyruvate formation during respiration in vitro, no significant difference between the contents of pyruvic acid of normal and avitaminous brains could be detected when the estimations were performed immediately after the death of the animal, that is to say, without any period of respiration in vitro. A possible explanation is that although avitaminous brain tissue does produce abnormally large amounts of pyruvic acid in vivo, this substance is not detectable owing to the fact that it largely diffuses out into the blood stream. The pyruvic acid in the blood of normal and avitaminous pigeons and rats was therefore investigated. Our results show that there is a marked accumulation of pyruvic acid in the blood of both these animals when in a state of avitaminosis B,. A preliminary account of this work has already been published [Thompson and Johnson, 1934].