“…Primary hepatocytes were obtained from the liver of a control rat (80-120 g) without any administration by using a collagenase perfusion method. 19) The isolated hepatocytes were resuspended in Dulbecco's modified Eagle's medium (DMEM; Nissui, Tokyo, Japan) supplemented with 20% (v/v) heat-inactivated fetal bovine serum (Biowest, Nuaille, France), 0.1 mM insulin and 1 mM dexamethasone, and cultured on type 1 collagen-coated 12-well plates (Asahi Glass Co., Tokyo, Japan) at a cell density of 2 Â 10 5 cells/mL. After 6 h of incubation at 37 C in a 5% CO 2 atmosphere, the medium was renewed to remove the unattached hepatocytes.…”