Plasma apolipoprotein E levels in hypertriglyceridemia.

A specific, precise and sensitive double-antibody radioimmunoassay for the measurement of human apolipoprotein E (apo E) was developed. Antibody specific to apo E was raised in a rabbit. This antibody did not crossreact with plasma low density lipoproteins (d = 1.030-1.063) and apo-proteins such as pao CII, CIII, AI and AII. Mean plasma level with SD of apo E in 29 normalipidemic subjects was 9.5 +/- 1.8 mg/100 ml. Plasma apo E concentrations in 25 hypertriglyceridemic patients with plasma triglyceride concentrations ranging from 169 to 1190/mg/100 ml correlated positively with plasma triglyceride concentrations (r = 0.84, p less than 0.001). Among subjects with hypertriglyceridemia, there was a negative correlation between the apo E per mg triglyceride ratio and plasma triglyceride concentrations (r = 0.49, p less than 0.02). Plasma apo E levels did not show any correlation with plasma cholesterol concentrations. These results indicate that plasma apo E is closely associated with plasma triglyceride levels, which suggests a possible connection of this apoprotein with the metabolism of plasma triglyceride.