Expression of cholesterol 7alpha-hydroxylase and delta(4)-3-ketosteroid 5beta-reductase genes in rat pancreatic hepatocyte-like cells.

Hepatocyte-like cells have been observed in the pancreas of the rat. We examined the bile acid biosynthetic function of these cells to determine whether they were real hepatocytes. This study investigated the existence of two liver-specific enzymes involved in bile acid biosynthesis (cho- lesterol 7 a -hydroxylase and D 4 -3-ketosteroid 5 b -reductase) in the hepatocyte-like cells. We could demonstrate cholesterol 7 a -hydroxylase activity and its circadian rhythm in the hepa- tocyte-like cells. Northern blot analysis demonstrated the expression of messenger RNA for the 7 a -hydroxylase and D 4 -3-ketosteroid 5 b -reductase in the pancreatic hepatocyte- like cells. To measure the amount of the messenger RNA, we used the competitive polymerase chain reaction method for the 7 a -hydroxylase. This quantitation revealed the exist- ence of a circadian rhythm of cholesterol 7 a -hydroxylase messenger RNA in the hepatocyte-like cells. These results indicated that bile acid biosynthesis was performed in the pancreatic hepatocyte-like cells as noted as in the liver parenchymal cells. —Ando, Y., H. Ide, S. Kosai, R. Ka- mimura, Y. Maeda, S. Higashi, and T. Setoguchi. Expression of cholesterol 7 a -hydroxylase and D 4 -3-ketosteroid 5 b - reductase genes in rat pancreatic hepatocyte-like cells. J. Lipid Res. 1999. 40: 1793-1798.