Dynamics of the Enterohepatic Circulation of Bile Acids: Postprandial Serum Concentrations of Conjugates of Cholic Acid in Health, Cholecystectomized Patients, and Patients with Bile Acid Malabsorption

The effect of three liquid meals on the serum level of conjugates of cholic acid was determined by radioimmunoassay. In eight healthy subjects, these bile acids peaked 90 to 120 minutes after each meal, and returned to base line by four hours. This pattern was meal related because the values remained at base line in four subjects undergoing a 22-hour fast. In five patients with cholecystectomy, conjugates of cholic acid increased to lower maxima after the first meal, and then remained elevated throughout the day, returning to base line 14 hours after the evening meal. In six patients with bile acid malabsorption (after ileal resection), the postprandial increase after the first meal was smaller than in health; an increase was barely detectable after the mid-day meal and occurred after the evening meal. In subjects with normal liver function, postprandial conjugates of cholic acid appear to indicate the dynamics of the enterohepatic circulation of bile acids; the level depends in part on intestinal absorption of these bile acids, which depends in turn on gallbladder contraction and efficient ileal absorption. (N Engl J Med 291:689–692, 1974), BILE acids are formed in the liver from cholesterol, stored and concentrated in the gallbladder, and secreted into the intestine after the ingestion of a meal. After facilitating the absorption of dietary lipids, bile acids are themselves absorbed by the small intestine, most efficiently in the ileum, and then carried in the portal blood to the liver, where resecretion into the bile occurs. The efficiency of the hepatic clearance from portal blood maintains serum bile acid concentrations at low levels.