Studies on the Physiological Functions of Thiamine

Rats made deficient by thiamine deprivation or by injections of the thiamine antagonists oxythiamine and pyrithiamine were divided into two groups, one being fed a basal diet and the other this diet containing 20% of sorbitol, in order to study the effects of sorbitol on growth and on α-keto acid metabolism in the three types of thiamine deficiency. In all cases where the deficiency caused a decrease in the growth or the oxidative decarboxylation of pyruvate or α-ketoglutarate in the tissues, the feeding of 20% of sorbitol in the diet reversed this effect and resulted in essentially normal levels in the tissues. On the other hand, the elevations in blood pyruvate associated with thiamine deprivation and OTh treatment were not decreased to normal by sorbitol feeding. The PTh treatment failed to affect the blood pyruvate either with or without sorbitol. The changes in total α-keto acids in blood paralleled those for pyruvate and were largely due to the changes in pyruvate.