RÉSUMÉ
We investigated the effects of medium supplementation with increasing amounts of different fatty acids on HepG2 cell cholesterol biosynthesis and esterification. Up to 200 microM 16:0 led to an increase in cholesterol secretion/synthesis of 60%/40%; 18:1, 18:2, or 18:3 decreased secretion/synthesis by 35%/25%, 65%/65%, and 60%/60%; 80 microM 20:5 caused a reduction of 75%/50%. Compared to 200 microM 16:0, 18:2 led to a 50% reduced cellular cholesterol ester biosynthesis; the effect of 30 microM 20:5 was comparable to that of 18:2 while the addition of 200 microM 18:1 raised esterification. Supplementation of 18:2 reduced the cellular cholesterol ester content by 50%; 16:0 led to an increase of 80%. The effects of saturated and unsaturated fatty acids seem to be related to their number of double bonds and could be due to changes in membrane phospholipid fatty acid composition.