Cholesterol-4-C 14 and Bile Acids in the Guinea Pig. ∗

Summary

In adult guinea pigs with biliary tract fistulae and stable enterohepatic bile acid pool, cholesterol-4-C¹⁴ was converted into 3 labeled bile acids (3a, 7a, 12a-trihydroxycholanic, 3a, 7a-dihydroxycholanic and 3a-hydroxy, 7-ketocholanic acid). This conversion occurred independently of enteric passage, 3a, 7a, 12a-trihydroxycholanic (cho-lic) acid appearing in relatively low but gradually increasing concentration during the first 9 hours of free flow and of continuous cycling. After one or more days of continuous enterohepatic cycling, 3a, 7a, 12a-trihy-droxycholanic acid was the predominant labeled bile acid, maintaining a relatively high level until termination of the experiment 18 days after injection of cholesterol-4-C^14.