Abstract
It is well known that thiamine, when taken with food or as medicine, is first phosphorylated in vivo and then takes part in the metabolism. In order to find out what organs relate to thiamine phosphorylation, we observed the free and conjugated thiamine contents in the blood and tissues after administration of thiamine to hepatoectomied rabbits and frogs. When thiamine was injected to rabbits, of which the blood streams toward the liver and intestines were occluded, the thiamine in blood remained in free form for several hours. Compared with intact animals, a very small quantity of conjugated thiamine was observed in the blood, kidnies and muscles of hepatoectomied frogs and rabbits with Eck's fistula. When thiamine was injected to hepatoectomied rabbits, the greater part of it remained in free form without being phosphorylated for a long time. The blood conjugated thiamine level in vena hepatica was higher than in vena portae in intact animals, and administration of thiamine in aorta abdominalis immediately elevated the blood conjugated thiamine level in vena portae. In this case, too, the conjugated thiamine level in vena hepatica was much higher than in vena portae. These results suggest that the phosphorylation of thiamine takes place chiefly in the liver, though intestinal tissues also play a little role.
