Fig. 7.

Rates of HDL-CE clearance and uptake by the liver, bile acid pool size and composition, and rates of fecal sterol excretion. Rates of hepatic HDL clearance were measured (A, B) and, along with the concentration of cholesteryl esters in the HDL fraction of these two genotypes, were used to calculate the rates of HDL-CE uptake by the liver (C). The amount of bile acid present in the liver, biliary tract, and entire small bowel combined was measured and is presented as the bile acid pool size (D). The ratio of cholic acid to muricholic acid in this pool was also determined (E). The molar ratios of bile acid, phospholipid, and cholesterol in bile obtained from the gallbladder was quantitated (F). In a separate group of animals, feces were collected for determination of the daily output of both neutral and acidic sterols (G). The asterisk identifies those values that are significantly different (P < 0.05) from the corresponding values in the abca1^+/+ mice. Each column represents the mean ± 1 SEM of data in 6 to 10 animals in each group in the first set of data (A–C), five animals in the second set (D, E), four animals in the third (F), and 10 animals in the last set (G).