Estrogen administration early in life and the development of atherosclerosis

Effect of high doses of estrogen administration early in life on aortic atherosclerosis and cholesteryl ester metabolism was investigated in female atherosclerosis-susceptible (White Carneau) pigeons. Long-term estrogen (in doses of 0.25 mg/kg/day) administration significantly increased the severity of aortic atherosclerosis. Following short-term administration of estrogens, the concentration of aortic cholesterol was significantly higher in estrogen-treated pigeons with a marked increase in cholesteryl esters. Determination of activities of enzymes concerned with cholesteryl ester metabolism in aorta indicated an increase in cholesteryl ester synthetase, while no difference was noted in the three cholesteryl ester hydrolases located in various subcellular fractions of aorta. These results suggest that the increase in aortic cholesterol content following estrogen treatment may be partly responsible for the noted increase in atherosclerosis following long-term administration of estrogens to female pigeons.