INTESTINAL AND HEPATIC TRANSPORT OF CHOLATE AND ORGANIC DYES

The 3-hr cumulative biliary appearance of a bile salt and three representative organic dyes was studied in rats anesthetized with sodium pentobarbital. The substances were administered in one of the following locations: a branch of the portal vein, a 20-cm isolated loop of proximal jejunum, or a similar loop of distal ileum. Average biliary recoveries of 10 mg cholate, bromsulfonphthalein, diiodotetrachlorofluorescein (rose bengal) or phenolsulfonphthalein (phenol red) introduced slowly into the portal circulation were 97, 97, 68, and 23%, respectively. The respective recoveries of 30-mg quantities of these four substances placed in the intestinal loops were 43, 5, 2, and 1% proximally and 90, 5, 5, and 0.4% distally. These observations confirm the presence of a specific intestinal transport mechanism for cholate with maximal activity in the distal ileum. However, the three representative organic dyes are shown not to be carried by the intestinal bile salt transport mechanism and their movement from gut lumen to portal vein blood should be ascribed to a passive process.