[Effect of S-propyl-mercapto-cysteine on lipid metabolism (author's transl)]

When intra tissue reduction of thiamine propyldisulfide (TPD) occurs the following changes take place : TPD+cysteine leads to thiamine+propyl-mercapto-cysteine (PMC). We have reports that PMC has an effect of blood cholesterol lowering or not. In the present paper experiments were conducted to determine whether the effect of TPD on blood cholesterol lowering lies in PMC or not. The following results were obtained. 1) It was shown that when PMC was added to liver homogenate, no change was seen in the biosynthesis of cholesterol where TPD inhibited the biosynthesis. 2) When administered to normal animals while PMC showed no change in the total blood cholesterol value, TPD produced a decrease. While no change in total liver cholesterol value was induced by both, total liver, fatty acid showed a decrease by both. The biosynthesis of liver cholesterol from acetate-1-14C showed a decrease by both PMC and TPD, while the uptake from mevalonic acid-2-14C showed no change by both. The uptake of total liver fatty acid from acetate-1-14C while showing no change by PMC, showed an increase by TPD. 3) In cholesterol fed animals, the increase of blood cholesterol and total liver cholesterol was inhibited by TPD but PMC showed no effect. The biosynthesis of liver cholesterol from acetate-1-14C, showed an inhibitory effect on the lowering of biosynthesis in cholesterol fed animals by both TPD and PMC. And it was shown that the effect of TPD was larger. The total fatty acid value and the lowering of the uptake of total liver fatty acid from acetate-1-14C was inhibited to a similar extent by both TPD and PMC. From the above results, it may be said that even when PMC, a degenerative product of TPD is administered, either no effect is seen on the cholesterol metabolism or even when there is an effect, it would be negligible. Therefore, it may be surmized that the total structure of TPD exerts its effect on cholesterol and while the effect on fatty acid metabolism shows the same degree as TPD no characteristic features are seen.