Although biliary secretion of phospholipids and cholesterol is principally dependent on bile-salt secretion, at low bile-salt output secretion of some lipids continues; also the amount of cholesterol secretion is more than that of phospholipid under these conditions, but the origin of this cholesterol is not known. Taurodehydrocholate was continuously infused in isolated perfused rat livers under recycling perfusion conditions and the biliary lysosomal output and lipid output measured. The rate of acid phosphatase and beta-glucuronidase output increased 30-60 and 60-90 min respectively after liver isolation under these conditions. The rate of output of cholesterol and phospholipid increased in all the samples collected from taurodehydrocholate-infused livers. The increase in cholesterol output was approximately twice that of phospholipid output, leading to an increase in the cholesterol/phospholipid ratio in the bile.
