A Reinvestigation of Methylglyoxal Accumulation in Thiamine Deficiency

Abstract

Thiamine-deficient animals did not excrete large quantities of methylglyoxal, but their tissues accumulated the intermediate when incubated with fructose-diphosphate. D-Lactic acid was excreted by both normal and thiamine-deficient rats, but the ratio of D/L-lactic acid was significantly greater in deficient animals. The pyruvate/lactate ratio increased in deficient animals, especially the pyruvate/L-lactate ratio. Since glyoxalase and D-lactate oxidase were present in normal and deficient rats in significant amounts, it was proposed that most formed methylglyoxal was further metabolized to pyruvate and that this pathway is at least partially responsible for increased pyruvate/lactate ratios.