Comparative effects of cimetidine on biliary lipid secretion in fasted and fed rats

The effect of cimetidine on biliary lipid secretion has been investigated in fasted and fed rats with biliary drainage for 4 h after a single intraperitoneal administration at a dose of 120 mg/kg body weight. Bile flow, bile acids, cholesterol and phospholipids in bile have been determined. In intact rats similarly treated, serum bile acids, cholesterol and phospholipids have been determined. Biochemical and morphological studies have been conducted on the liver tissue in both experiments. Bile flow and bile acid secretion were not affected by cimetidine in fasted rats, but, 15 min after administration of the drug, fed rats showed an increase of the molar percentage of cholic acid together with a decrease of deoxycholic acid, a decreased secretion of cholesterol and an increased secretion of phospholipids. The values of these biliary lipids were in the range observed in fasted animals, so that the drug appeared to 'mimic' the effect of fasting. These findings could be related to altered vascular properties of the gastro-intestinal wall induced by cimetidine, leading to interference with intestinal postprandial hyperaemia and capillary permeability, so that there appears to be a conversion of bile composition from a digestive to an interdigestive pattern.