JL: Dietary fat clearance in normal subjects is regulated by genetic variation

Apolipoprotein E (apo E) plays an important role in receptor mediated clearance of lipoprotein particles from plasma. Com-mon genetic variation in apo E exists with three alleles coding for proteins called E2, E3, and E4. In in vitro receptor binding assays, E2 binds poorly, whereas E3 and E4 function normally. Recently, the apo E phenotype has been shown to have an effect on low density lipoprotein (LDL) cholesterol levels with levels in subjects with E2 lower and E4 higher than E3. We have examined the effect of the apo E polymorphism on dietary fat clearance using the vitamin A-fat loading test, which specif-ically labels intestinally derived lipoproteins with retinyl pal-mitate (RP). 27 normal subjects were studied, 10 with E3/3,