抄録
An active transport of thiamine from chick intestine was proved by means of the in vitro tissue accumulation method. The intracellular to extracellular concentration ratio in the intestinal tissue was found to exceed unity with respect to free thiamine, indicating a transport against a concentration gradient. All of the other requirements for the concept of an active transport, that is, the saturation kinetics, the temperature dependency, the energy requirement and the competitive inhibition by structural analogues were also found to be filled for the thiamine transport. It was found that chloroethylthiamine has no inhibitory effect on the thiaminokinase activity, while inhibits the thiamine uptake competitively. These results suggest that there is a carrier system for thiamine transport which is not dependent upon the phosphorylation process. A possibility that the property of chloroethylthiamine to inhibit the active transport of thiamine competitively plays an important role in exerting its anticoccidium activity was pointed out.
