Inhibition of ACAT activity after 7-oxo-PGI2 treatment in cholesterol-fed rabbits

It has been supposed that prostacyclin (PGI2) and its analogues have important antiatherogenic effects. The aim of this work was to test the effect of PGI2 and 7-oxo-PGI2- (a stable analogue of PGI2) (6) treatment on the acyl CoA: cholesterol-acyltransferase (ACAT) activity in the aortic wall of rabbits. The rabbits had been previously fed with cholesterol and treated with PGI2 and 7-oxo-PGI2 intravenously. Cholesterol feeding increased ACAT activity compared to the control group which was not fed with cholesterol: 16.84 nmol/mg prot./h and 10.03 nmol/mg prot./h, respectively. PGI2 treatment of the cholesterol fed group did not cause a significant decrease, while 7-oxo-PGI2 treatment significantly decreased aortic ACAT activity compared to the cholesterol-fed control group; 14.31 nmol/mg prot./h; 11.53 nmol/mg prot./h and 16.84 nmol/mg prot./h, respectively. The decrease found in the ACAT activity after PGI2 and 7-oxo-PGI2 treatment are new data for the protective effect of these agents against atherosclerosis.