II. BLOOD PYRUVATE LEVELS IN THE RAT, PIGEON, RABBIT AND MAN THE physiology and biochemistry of vitamin B1 bave been recently reviewed [Peters, 1938; Cowgill, 1938]. While the role of vitamin B1 in the mammalian organism remains undefined there is now much evidence in support of the view that the primary biochemical lesion in Bl-deficiency is the inability of the cell to metabolize pyruvic acid [Peters, 1936].The accumulation of pyruvic acid in the blood in vitamin B1-deficiency was first shown by Thompson & Johnson [1935] in England, using rats and pigeons, and byPlatt&Lu [1935] inChina on human beri-beri cases. The above-mentioned authors were able to relate the increase of bisulphite-binding substances (B.B.S.), expressed as pyruvic acid, to Bl-deficiency, by demonstrating that the raised
THE results of in vitro work have led to the postulation of several possible paths of pyruvate removal in animal tissues; namely (1) the scheme of Toenniessen & Brinkmann [1930] whereby 2 mol. of pyruvic acid are reduced to form 1 mol. of succinic acid, and the latter is then converted,successively into fumaric, malic, oxaloacetic and 1 mol. of pyruvic acid, (2) the scheme of Krebs & Johnson [1937] whereby the oxidation of pyruvate is preceded by an anaerobic change; 2 mol. of pyruvate interact to form 1 mol. each of lactic acid, acetic acid and C02, (3) the oxido-reduction between pyruvate and an aldehyde, such as triosephosphate, giving lactic acid and an acid such as phosphoglyceric acid, (4) a direct oxidation Jike that which exists in the brain [Peters, 1936; 1938; Ochoa & Peters, 1938]. It is also relevant that according to Weil-Malherbe [1937] pyruvic acid is removed more effectively from brain slices in the presence of glucose than in its absence. However, little is known about pyruvic acid metabolism in vivo. The object of the following experiments is to throw some light on these questions. Rabbits were used in most of the experiments. Instead of estimating the changes following administration of pyruvate in the blood, urine or excreta after some time, it was decided to load the rabbit suddenly with a definite amount of pyruvate by intravenous injection lasting for 1-2 min. and study the chemical changes resulting from this immediately after the injection, a few minutes later and in some instances 35 min. later, when the blood pyruvate level had returned to the pre-injection level. Experimental details All the rabbits were kept under resting conditions for at least 1 hr. before use, as previously described. Anaesthesia was begun by first giving a sedative dose of "Numal Roche" (1 ml. of 10 % solution per kg. body weight) and com
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.