Cholesterol metabolism in the rat sensitive to high cholesterol diet
Takeuchi, N.; Ito, M.; Yamamura, Y.
Japanese Journal of Experimental Medicine 43(6): 451-461
1973
ISSN/ISBN: 0021-5031 PMID: 4361508 Document Number: 68320
Wistar rats of both sexes were fed on stock diets with 1.5% or 0.1% cholesterol. Rats in which serum cholesterol increased by more than 200% when on the high-cholesterol diet were described as showing a good response. Those in which the value increased by less than 30% were described as showing a poor response. There was no difference between these 2 groups in the rate at which orally administered cholesterol-4-14C was absorbed from the intestine, or in the rate at which acetate-1-14C was incorporated in vitro in hepatic cholesterol. However, the rate at which cholesterol-4-14C disappeared from the peripheral blood after it was injected into the tails of rats was slow in rats showing a good response, compared with those showing a poor response. Also, when cholesterol-4-14C was given to rats with bile fistulae, the recovery of radioactivity during 48 h was less in rats showing a good response. Hydroxylation in vitro at C-7 of cholesterol by the livers of the good-response group was impaired in comparison with that of the poor-response group. Other experiments showed that although serum triglyceride concentrations were similar in both groups in old age, the rise in serum cholesterol due to ageing was higher in rats showing a good response. It was concluded that sensitivity to dietary cholesterol which results in high serum cholesterol values is probably associated with impaired 7 alpha -hydroxylation of the compound. It appears that this metabolic defect is heritable.