Biochemical Factors Involved in the Anorexia of Thiamin Deficiency in Rats

Rats were made deficient in thiamin diphosphate by thiamin deprivation and by treatment with oxythiamin or pyrithiamin, and the pyruvate dehydrogenase and transketolase activities of the intestinal mucosa were measured at various stages of the development of the deficiency. Transketolase activity decreased sooner and more markedly than did pyruvate dehydrogenase activity, and the decrease in transketolase activity correlated most closely with the development of anorexia symptoms. It is suggested that the decrease in transketolase activity may be one of the biochemical lesions related to the development of anorexia, although other possibilities are not excluded by the data presented.