Role of bile and pancreatic juice in cholesterol absorption and esterification

Absence of bile and pancreatic juice in the intestinal tract totally abolished absorption of cholesterol-4-C14 into thoracic duct lymph. Similarly, intestinal cholesterol esterase activity approached zero in animals lacking both bile and pancreatic juice. Intestinal cholesterol esterase could still be demonstrated in animals deprived of pancreatic juice, but which received an infusion or intragastric administration of bile salts. Absorption of cholesterol was shown to occur even in the complete absence of pancreatic juice, provided bile salts were present in the intestinal tract. Some synthesis of cholesterol esterase by the intestinal or reactivation of residual cholesterol esterase in the presence of bile salts is postulated. Thus, pancreatic secretion is not absolutely required for cholesterol absorption, although it has a stimulating effect in the presence of bile salts. This effect is attributed to its cholesterol esterase content. In the presence of bile salts, the process of esterification is postulated to be a rate-limiting step during intestinal absorption of dietary cholesterol.