Acute and reversible fatty metamorphosis of cultured rat hepatocytes

Rat hepatocyte cell line M6 B347 and J525, among which only M6 is slightly deviated from diploidy, showed marked microvesicular fatty metamorphosls in response to treatment with Tweens at concentratlons of 0.05–0.025% In Eagle's minimum essentlal medium (MEY). Within 24h treated cells became fatty at 100% In frequency and filled with small lipld droplets, as revealed by fat stalning or at the ultrastructural level. Fatty hepatocytes, however, took again non‐fatty morphology 72 h after withdrawal of Tweens from the culture medium. Growth of the cell exhibited mlld retardation at the early phase of the treatment but almost simllar cell density to that of control cells was achleved 24 h after the treatment. Other detergents without fatty‐acld moiety, including NP‐40, triton X‐100, sodium deoxychollc acld and sodium cholic acld, were ineffective to induce fatty change. Oleate, a fatty‐acld molety of Tween 80 or 85, and linolate caused reversible fatty metarnorphosls of the cell llnes at concentratlons of 1.9X10‐4 mol/L or more and 3.8X10‐‐4 mol/L or more, respectively. Ethanol Induced mild steatosls of the cell lines and enhanced fatty change by linolate. Hepatic fatty acid‐binding proteln was not detected in the cell lines before or after the Induction of fatty change. These results Indicate that fatty acid Itself Is directiy Incorporated In cultured rat hepatocytes and expelled 3 days later without apparent cell degeneration.