Bile acid excretion by the rat: Nutritional effects

Abstract

A modification of several published procedures for bile acid determinations has been developed, and this procedure has been applied to the 24-hr, biliary excretions of rats prepared for 15 days on a series of dietary regimens. It has been established that: 1. 1. Cholesterol supplementation of the basal synthetic diet or of Purina Chow resulted in significantly increased biliary bile acid and cholesterol excretion. 2. 2. The levels of vegetable fat did not influence the biliary excretion of bile acids and cholesterol. 3. 3. The feeding of a commercial diet (Purina Rat Chow) resulted in a much higher bile acid excretion with a higher proportion as cholic acid than did any synthetic diet tested. 4. 4. The substitution of egg albumin for casein in the synthetic diet resulted in an increased bile acid excretion; however, the addition of methionine, cystine, or taurine did not produce a significant increase. 5. 5. The addition of brewer's yeast or desiccated liver to the diet or the administration of parenteral vitamin B 12 was without significant effect. 6. 6. Fasting decreased the bile acid excretion of rats previously fed Purina Chow but increased the excretion of rats fed the basal (sucrosecontaining) diet. The substitution of starch for sucrose in the basal dict resulted in a larger biliary excretion of bile acids and a larger proportion as cholic acid. Dextrose substituted for sucrose was without effect. 7. 7. Increasing the levels of Cellu-flour in the basal diet also resulted in an increased biliary bile acid excretion. The conclusion was drawn that sucrose and dextrose are inhibitors of biliary bile acid excretion in the rat.