Subcellular changes associated with culture of Chinese hamster fibroblasts in hyperlipemic medium

Chinese hamster fibroblasts grown in hyperlipemic rabbit serum, enriched 20-fold in total cholesterol, show accumulation of cholesterol ester to 5-6 times the normal level, whereas free cholesterol levels show minimal changes. Changes with serum concentration and time show the uptake to be saturable. Concomitant with accumulation of cholesterol ester, the median density of lysosomes as observed on analytical sub-cellular fractionation decreased markedly, indicating a lysosomal localisation of accumulated sterol. These changes were freely and rapidly reversible on return to normal medium. The implications of these findings and the potential use of the system as a model for investigation of the subcellular consequences of lipid uptake is discussed.