Bile salt transport in intestinal lymph of the rat.

The concentrations of conjugated cholate and chenodeoxycholate have been measured in samples of rat thoracic duct lymph, portal and systemic blood. Both these bile salts were present in lymph. After administration of a corn oil meal the flux of both these bile salts in lymph increased significantly (P less than 0.001; Student's t test), the cholate flux rising from 0.9 +/- 0.6 nmol/h (mean +/- SD) to 3.5 +/- 1.1 nmol/h postprandially and the chenodeoxycholate flux rising from 2.5 +/- 0.8 to 4.6 +/- 1.6 nmol/h. This postprandial increase in bile salt flux was due to both an increase in bile salt concentration and an increased lymph flow which rose significantly (P=0.007) from 0.5 +/- 0.2 to 0.7 +/- 0.2 ml/h. Biliary drainage significantly (P less than 0.001) reduced the flux of cholate and chenodeoxycholate in lymph to 0.08 +/- 0.05 and 0.17 +/- 0.10 nmol/h respectively. These biliary drained animals produced no significant rise (P greater than 0.1) in bile salt flux when fed the corn oil meal. The ratio of the concentrations of conjugated cholate to chenodeoxycholate in systemic and portal blood was 1.9:1 and 3.3:1 respectively. In contrast, this bile salt ratio was only 0.44:1 in lymph. These studies show that bile salts, in particular chenodeoxycholate, can pass directly from the intestine into lymphatics thus establishing an enterolymphatic circulation of bile salts.