Serum Cholesterol Esterification in Liver Disease

Abstract

Recent evidence indicates that the serum enzyme lecithin-cholesterol acyltransferase (LCAT) can esterify circulating cholesterol. The ability of serum to esterify ¹⁴C-cholesterol-labeled lipoproteins was used to assay LCAT acivity in 21 patients with liver disease, most of whom had disproportionately low levels of serum cholesterol esters. Activity was low in 14 patients, five having values under 5 μg of cholesterol esterified per ml per hour (control activities 20.4 to 34.1 μg per ml per hour, with a mean of 27.6). The defect was not due to circulating heat-stable inhibitors or to abnormal substrate lipoproteins in the patients' serum, but generally paralleled the severity of hepatic dysfunction. A direct relation existed between the patients' LCAT activities and the proportion of their serum cholesterol present as esters (r = 0.647, p less than 0.001).