Abstract
The daily dosis of 1mg of thiamine sulfuric acid ester (I) given intraperitonealy to albino rats on thiamine-deficient diet showed loss of their weights and even 10mg of (I) failed to promote their growth, while daily 10μg of thiamine-HCl in addition to 10mg of (I) showed the same growth curve as that responsible to 10μg of thiamine-HCl alone. The LD_<50> of (I) to mice was about 1mg/g weight and there was no difference between normal and thiamine-deficient groups. Thus no anti-thiamine activity of (I) to animals has been proved. One mg of (I) to 1μg of thiamine diphosphate showed no competitive inhibition to CO_2-evolution from pyruvate by yeast etiozymase, although (I) was proved to have a slight "Ochoa-effect"activity to etiozymase.
