Bile acid synthesis and intracellular and extracellular cholesterol concentrations in isolated rat hepatocytes: the effect of dietary cholesterol.
Bile acid synthesis in isolated hepatocytes prepared from rats given 1% cholesterol in the diet and incubated for 1 h in suspension was not increased compared to that in cells from control rats. When the hepatocytes were maintained in monolayer culture for 24 h, however, increased production of bile acid (X2.5) was observed in the cholesterol-fed group. The amount of bile acid synthesised during incubation in suspension was significantly correlated with intracellular unesterified cholesterol levels, but showed no correlation with intracellular esterified or medium cholesterol concentrations after 1 h. Bile acid production in hepatocytes maintained in monolayer culture was also significantly correlated with the intracellular unesterified, but not esterified, cholesterol content. In addition, in this case, there was a significant correlation with the levels of both unesterified and esterified cholesterol found in the medium after 24 h. These results suggest that the amount of cholesterol available to liver cells from extracellular sources has a role in the regulation of bile acid synthesis in cholesterol-fed rats, while the concentrations of esterified cholesterol stored within the cells are not important in this process.
Sutton
C M
CM
Department of Veterinary Basic Sciences, Royal Veterinary College, London, U.K.
Botham
K M
KM
D000818:Animals; D001647:Bile Acids and Salts / Q000096:biosynthesis*; D002478:Cells, Cultured; D002784:Cholesterol / Q000378:metabolism*; D002791:Cholesterol, Dietary / Q000494:pharmacology*; D005260:Female; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains
D001647:Bile Acids and Salts; D002791:Cholesterol, Dietary; D002784:Cholesterol