血漿

Enzymatic esterification in vitro of cholesterol by plasma was compared at timed intervals with rats fed on diets containing corn oil or hydrogenated coconut oil with or without the combination of cholesterol and cholic acid. Feeding the completely saturated cocount oil resulted in slightly decreased levels of plasma cholesterol and higher levels of cholesterol esterifying activity than was present in rats fed corn oil. The combination of corn oil with cholesterol and cholic acid resulted in lower levels of plasma cholesterol and higher enzymatic activity than the combination of hydrogenated coconut oil and cholesterol and cholic acid. The nature of fatty acids transesterified during the incubation was remarkably different in each group. In rats fed corn oil and cholesterol and cholic acid more than 70% of the increase in fatty acids transfered were saturated and monounsaturated in contrast to a value of about 70% polyunsaturated acids for rats fed corn oil alone. Feeding hydrogenated coconut oil alone or with cholesterol and cholic acid resulted in remarkable increases in saturated and monounsaturated acids during the plasma incubation. The combination of cholesterol and cholic acid with corn oil or with hydrogenated coconut oil produced a remarkable decrease in plasma polyunsaturated acid esters. The fatty acid specificity of cholesterol esterification by rat plasma was significantly heterogeneous in every groups, and there were high specific activities of the polyunsaturated acid esters after incubation with cholesterol-4-C^14, It was suggested that plasma cholesterol esterifying activity itself as well as the liver functions would have a possible significance on the metabolism of plasma cholesterol esters. Discussions were made on factors influencing the plasma cholesterol esterifying activity in rat plasma.