The effect on cholesterol synthesis of ligation of the common bile duct was studied in the rat. The bile ducts of rats were ligated; 24 to 48 hours later, estimates of the rate of cholesterol synthesis were made, either by injection of labelled water or acetate into the intact animal, or by incubation of slices or homogenates of the liver in the presence of 1-C14-acetate. These various criteria all indicated that cholesterol synthesis was increased following ligation of the bile duct. The average ratios of the rate of synthesis in the experimental animals to that in the controls were as follows:
1. Synthesis from C14-carboxyl-labelled acetate: (a) in the intact rat fed ad libitum, 19; (b) in liver slices from the fasted rat, 23; (c) in liver slices from the rat fed ad libitum, 4; (d) in cell-free homogenates from the fasted rat, >27; (e) in cell-free homogenates from the rat fed ad libitum, 17.
2. Synthesis from tritium-labelled water in the intact rat fed ad libitum, 4.