Serum albumin enhances the uptake of [3H]cholesterol from phosphatidylcholine vesicles by cultured human fibroblasts.

Cultured human lung fibroblasts, incubated with cholesterol/phosphatidylcholine vesicles (cholesterol: phosphatidylcholine molar ratio 1:1) incorporated vesicle [3H]-cholesterol linearly for at least 48 h by an exchange process without gaining sterol mass. The incorporation of [3H]cholesterol by the cells was markedly enhanced in the presence of purified bovine serum albumin. A fraction of the incorporated vesicle [3H]cholesterol was esterified by the cells.