Cholesterol metabolism in hamsters reared on diets with different effects on gallstone formation

Abstract

The incorporation of labeled acetate into cholesterol and the elimination of labeled cholesterol from the body was studied in three groups of hamsters reared on diets with known effects on gallstone formation in young individuals of this species. One group of hamsters received a diet producing abundant formation of cholesterol gallstones. This diet consisted of casein, 20%; glucose, 74.3%; plus salts, vitamins and choline chloride. A second group of hamsters received a diet which induced only a slight tendency to gallstone formation (or none at all). This diet differed from that of the first group by having rice starch instead of glucose as the carbohydrate component. The third group received a diet that has previously been found capable of bringing already-formed cholesterol gallstones into solution in the hamster. This (“curative”) diet differed from those given to the two other groups in that the 74.3% carbohydrate was replaced by 28.3% ground white rice, 36% dried yeast and 10% lard; further, the salt mixture contained added cupric sulfate. The per cent incorporation of intraperitoneally injected [1- 14C] acetate into cholesterol 70 ± 5 min after the injection was about 1.2% in the group given the glucose diet, about 0.15% in the group given the rice-starch diet, and about 0.4% in the group given the “curative” diet. The per cent incorporation remained higher in the group given the glucose diet than in the other two groups during the entire period during which measurements were made (up to 5 h). In the groups used for the incorporation study, the average contents of total cholesterol in the body, as mg per 100 g body weight, were 223 ± 13 for 8 animals in the group on the glucose diet, 166 ± 6 for 9 animals on the rice-starch diet, and 162 ± 6 for 8 animals on the “curative” diet. The rates of elimination of intraperitoneally injected [4- 14C]cholesterol in the three groups were compared by determination of the radioactivity of the total body cholesterol in animals killed 0, 2, 7 and 14 days after the injection. There was no significant difference between the three groups with respect to the time (10–12 days) required to bring the content of radioactive cholesterol down to 50% of the amount recovered immediately after the injection.