Cholesterol and bile acid synthesis in Hep G2 cells. Metabolic effects of 26- and 7α-hydroxycholesterol

Abstract

Using a human hepatoma (Hep G2) cell line that continually synthesizes 3β-hydroxy-5-cholenoic acid, lithocholic acid, chenodeoxycholic acid and cholic acid we have determined the metabolism and biological effects of 26-hydroxycholesterol and 7α-hydroxycholesterol. Addition of 26-hydroxycholesterol to the medium (6 μM) downregulated cholesterol and chendodeoxycholic acid synthesis. The predominant metabolite of 26-hydroxycholesterol was 3β-hydroxy-5-cholenoic acid. Cholesterol synthesis was not affected by the addition of 7α-hydroxycholesterol (6 and 12 μM). The predominant metabolite of 7α-hydroxycholesterol was chenodeoxycholic acid. In Hep G2 cells 7α-hydroxylation of 26-hydroxycholesterol is not well expressed.