Biotransformation of thiamine tetrahydrofurfuryldisulfide and its effect on potassium loss in isolated guinea-pig atria.

Abstract

In our previous paper, the authors had reported that the reduction in potassium content in isolated guinea-pig atria, kept in a potassium-free medium was prevented by thiamine tetrahydrofurfuryldisulfide (TTFD), added to the medium. In the present experiment, the attempt was to clarify whether or not this drug effect was caused by a biosynthetic thiamine originating from the TTFD. The effect of TTFD was observed in atria which had been treated once with TTFD, then washed out with Locke's solution, and finally subjected to a medium containing a low concentration of potassium ions without TTFD. As this effect seemed to be due to some biosynthetic compound originating from the TTFD, the amounts of thiamine in both the free and the bound forms were chemically estimated. A direct relation, however, could scarcely be found between the effect of TTFD and the amount of biosynthetic thiamine. The effect of TTFD was therefore assumed to be produced by the biotransformation of TTFD in the atria.