1979 Volume 6 Issue 4 Pages 599-606
Lipid metabolism in the arterial wall plays an important role in the formation of atheroma (1). Glavind et al. reported that lipoperoxide increased in atheromatous lesion (2). Therefore the experiments were carried out to clarify the relationship between lipoperoxide and the changes of enzyme activities concerning lipid metabolism in the arterial wall of tocopherol deficient rats fed for 16 weeks. Lipoperoxide, which was estimated as thiobarbituric acid reactive substance (TBA-RS), increased in the brain, the lung, the liver and the arterial wall of tocopherol deficient rats compared with these of tocopherol supplement rats. Both acid cholesterol esterase and acid lipase which were present in lysosome as previously reported (3), were decreased significantly in the arterial wall extracts of tocopherol deficient rats compared with those of tocopherol supplement rats. These results suggest that lipoperoxide might cause a decrease in these lysosomal enzyme activities. These facts suggest that decreased cholesterol esterase in the arterial wall of tocopherol deficient rats might cause the accumulation of cholesterol ester in lysosome, because cholesterol ester was less hydrolysed.
Acyl-CoA synthetase, triglyceride synthesizing activity and cholesterol ester synthesizing activity, which were considered to be present in microsome (3), decreased and only cytidine diphosphatecholine 1, 2-diacylglycerol choline phosphotransferase activity increased in the arterial wall extracts of tocopherol deficient rats. The mechanism of decrease or increase in these enzyme activities in this experiment must be further investigated.
Ratio of synthesis to hydrolysis of cholesterol ester in microsome was decreased in tocopherol deficient rats compared with that of tocopherol supplement rats. This ratio decreased in high cholesterol diet rats (4). Therefore, these results suggest that the changes in these enzyme activities might not cause cholesterol ester deposition in microsome of the arterial wall in tocopherol deficient rats.
1. Chobanian, A. V.: J. Lipid, Res. 13: 201, 1972.
2. Glavind, J. et al.: Acta Path. Microb. Scand. 30: 1, 1952.
3. Shirai, K. et al.: Proc. J. C. B. L. 20: 121, 1978.
4. Matsuoka, N. et al.: J. Jap. Atheroscler. Soc. 6: 121, 1978.
