The effect of thiamine deficiency on the glucose oxidative pathway of rat erythrocytes.

Thiamine pyrophosphate has been demonstrated recently to be an essential cofactor for the transketolation of pentose to heptulose in the hexose monophosphate shunt in addition to its well known function in pyruvate utilization by animal tissues (l-4). The observation that the glucose oxidative pathway of mammalian erythrocytes may be studied in vitro in the absence of interfering oxidative phenomena by the addition of methylene blue (5) made it possible to determine the effect, if any, on the transketolase reaction by acute thiamine deficiency, in this tissue. The data to be presented demonstrate that rat erythrocyte transketolase activity is reduced by the removal of thiamine from the diet. This lends further support to the argument that methylene blue activates the glucose oxidative pathway in erythrocytes, and, in addition, furnishes an assay for evaluation of thiamine nutrition of animals.