抄録
1. Optical isomers of hydroxyethylthiamine (DL-, D- and L-HET), together with its two alkyl homologues, DL-hydroxypropylthiamine (DL-HPT) and DL-hydroxyisobutylthiamine (DL-HIBT), were examined for their vitamin B1 activity, using thiamine-deficient rats and rice-birds as test animals.
2. When orally administered, in a daily dose equivalent to 10μg of thiamine, to rats which had been maintained on a thiamine-deficient diet, all these compounds showed perfect thiamine activity, bringing about immediate increase of growth rate. Their effects were indistinguishable from that of thiamine and, unexpectedly, no difference was observed between the activity of D- and L-isomers of HET.
3. To rice-birds fed a thiamine-deficient diet, each compound was orally administered in a daily dose equivalent to 3μg of thiamine. While the control birds died on the 10th and 11th days with noticeable decrease in body weight, those receiving test compounds other than DL-HIBT, as well as thiamine, remained healthy through the experimental period of 20 days. The effect of DL-HIBT, however, was less marked and three out of five died within the period.
