Effect of cholestyramine in early weaning on later response to serum and fecal steroid levels and cholesterol 7 alpha-hydroxylase activity to high-cholesterol diet in ExHC rats.

Male ExHC (exogenous hypercholesterolemic) rats were either prematurely weaned at 17 days of age or allowed to nurse until 35 days of age. The prematurely weaned rats were either fed a diet containing cholestyramine or cholestyramine-free diet until 35 days of age. Cholestyramine supplementation markedly increased fecal bile acid excretion and modified the composition. After giving a stock diet for 7 weeks, all rats received a cholesterol-enriched diet for 9 weeks. The serum cholesterol level in later time was not affected by early dietary manipulation. The activity of hepatic cholesterol 7 alpha-hydroxylase and fecal bile acid excretion at the end of the cholesterol challenge decreased in the cholestyramine-pretreated group, when compared to the normally weaned group. Fecal excretion and the ratio of the secondary (deoxycholic and lithocholic acids) to the primary (cholic and chenodeoxycholic acids) bile acids significantly decreased in the early cholestyramine-treated group. These results suggest that a modification of bile acid metabolism in early life may strongly influence the hepatic and possibly colonic bile acid metabolism in later life, when challenged with a high-cholesterol diet.