Increased biliary cholesterol secretion in alloxan diabetic mice.

Plasma and liver cholesterol levels and biliary cholesterol, phospholipid and bile acid concentrations were examined in normal and alloxan diabetic mice fed ordinary and 0.5 per cent cholesterol diets. The plasma and liver cholesterol levels markedly increased in the diabetic mice, and the cholesterol diet further increased the liver cholesterol level but not that in the plasma. The gallbladder bile weight increased in the diabetic mice, but not after the cholesterol diet. The biliary lipid concentrations markedly increased in the diabetic mice, and the increases of the cholesterol and phospholipids exceeded that of the bile acids, resulting in increases of the cholesterol molar concentration ratio (mole percent) and the lithogenic index. The cholesterol diet increased the biliary cholesterol concentration and slightly the phospholipid, but not the bile acids. Therefore, the cholesterol mole percent and the lithogenic index increased. Among the biliary bile acid composition, cholic and deoxycholic acids increased and beta-muricholic acid decreased in the diabetic mice, whereas the cholesterol diet feeding decreased cholic acid and increased chenodeoxycholic and alpha-muricholic acids. These data suggest that the mechanism of the increase of biliary cholesterol secretion in diabetic mice is different from that after cholesterol diet.