Abstract
1. In the gastrointestinal tracts of thia-mine deficient rats about 5 μg. of thiamine is always found until their death, but it is assumed that this is not utilized by the rats.
2. When 2.5μg. of thiamine is administer-ed orally daily, the rats grow up to about 80-90g. and then stop growing. On the other hand, when 5 μg. is administered orally daily, they grow up to about 150g. and then stop growing. In both cases 5-6 μg. of thiamine can be found in the gastrointestinal tracts, and the amount of thiamine in the vital organs is almost the same as when no thia-mine is administered.
Daily administration of 2.5 μg. of thiamine maintains the health condition of the rats up to about 80g. of body weight, and daily ad-ministration of 5μg. thiamine maintains the helth condition up to about 150g.
3. The minimum amount of thiamine necessary for curative treatment of the rats in the fourth or fifth week of thiamine defi-ciency was found to be between 2.5μg. and 5μg.
The authors are deeply grateful for his encourage-ment to Prof. S. Tazaka, in whose Department this work was done. The authors are also grateful to Dr. T. Takagi for his helpful advice.
