Bile fistula rats, ranging in weight from 200 to 300 g, were continuously injected into the intestine with 2.6, 5, 7.5, 10 and 15 mg sodium taurochenodesoxycholate (NaTCD) per hour. The excretion of cholic acid was determined, and it was found, that injection of 5–10 mg XaTCD per hour, depending on the weight of the rat, brought about a very appreciable decrease in the formation of cholic acid as compared to non‐injected bile fistula rats. In the case of rats weighing approx. 200 g, the values found are of the same order of magnitude as is calculated for the synthesis of cholic acid in the intact rat.

It is concluded, that the concentration of bile acids supplied to the liver via the portal blood, influences the rate of synthesis of bile acids in the liver.