Abstract
Cholesterol contents of four subcellular fractions of the rat liver and intestine and the distributions of radioactive cholesterol to them were estimated after an oral administrations of labeled cholesterol. The change of the distribution of labeled cholesterol to these hepatic subcellular fractions was also examined in the rats fed with a high cholesterol diet.
The ratios of cholesterol to protein contents in every four subcellular fractions of intestine were higher than those in the corresponding fractions of the liver. But the percentages of ester form to total cholesterol were almost the same in the corresponding fractions both in the liver and intestine.
Percent distribution of the ingested labeled cholesterol to the particle fractions was identical in both liver and intestine, though the distribution rate to the cytosol in the intestine was lesser than those in the liver. The ratio of ester form in labeled cholesterol was larger in cytosol fraction than in other particle fractions in both liver and intestine.
Percentage of distributed radioactive cholesterol to hepatic microsomes was decreased and that to cytosol was increased after the cholesterol administration. The ratio of ester fraction in labeled cholesterol was increased in the cytosol and decreased in the microsomal fraction.
In conclusion, the difference of negative feedback control between liver and intestine in cholesterol synthesis by oral administration of cholesterol can not be accounted by subcellular distribution of exogenous cholesterol, and the change of subcellular distribution in the liver after cholesterol feeding might be related to the metabolic changes of cholesterol.
