SH compounds and atherosclerosis.

Fatty acid peroxides have been found in the atherosclerotic human aorta. Glavind found a correlation between the extent of the atherosclerot ic changes and the content of lipid peroxides. These lipid peroxides are very toxic to the tissues. There are several compounds in the tissues to counteract the toxicity of peroxides in vivo, i.e. SH compounds, ascorbic acid, or tocopherol. · It may be inferred that an increase of peroxides and a decrease of SH compounds occur in the experimental atherosclerotic aorta and that the administra tion of such reducing substances as ascorbic acid or SH compounds reactivates the respiration of the aorta inhibited by peroxides and retards the atherogenesis. It may be also supposed t hat a decrease of SH compounds occurs in the human atherosclerotic aorta. From these considerations the pres ent invest igations were performed. In the rabbits fed cholesterol, a decrease of nonpr otein SH content and an increase of TEA reactive substances were observed in the aorta at the stag e when the r eduction of r espiratory activity was not revealed. Furth ermore, a decrease of total SH content was observed· in the serum, while total SH, nonprot ein SH contents and SDH activity were normal in the liver. In the rabbits fed cholesterol with concomitant administration of ascorbic acid or SH compounds, the grade of atherosclerosis and the abnormality of total cholesterol and total SH contents were improved. The development of atherosclerosis was r etarded as compared with the control, while the abnormality of lipids in quant ity and of fatty acid compos ition was not improved. Nonprot ein SH content in the human atheros clerotic abdominal aorta decrea sed as compared with the normal aorta. From these results, it may be concluded on atherogenesis that a damage of protein induced by nonenzymatic peroxidizing lipid-protein reaction exists in the serum and aorta.