On the Composition of the Bile Acid Fraction of Rabbit Feces and the Isolation of a New Bile Acid: 3a, 12a-Dihydroxy-5a-cholanic Acid BILE ACIDS AND STEROIDS 136*
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چکیده
The main primary bile acid formed from cholesterol in rabbit is cholic acid (2).r During the enterohepatic circulation of bile, cholic acid is extensively transformed into deoxycholic acid by the action of intestinal microorganisms, and deoxycholic acid is normally the predominant bile acid in rabbit bile (2). Small amounts of other bile acids have been isolated from rabbit bile. In 1936 Kishi (3) described the isolation of lithocholic acid and of two dihydroxylated cholanic acids, crand /3-lagodeoxycholic acids. The structures of the latter two acids were not established. Oxidation of cr-lagodeoxycholic acid with chromic anhydride gave 3,12-diketo-5/3-cholanic acid, but the oxidation product of /%lagodeoxycholic acid, a diketocholanic acid as judged from carbon-hydrogen analysis, could not be further identified. The melting point reported by Kishi (3) for the oxidation product of &lagodeoxycholic acid is the same as that of 3,12-diketodacholanic acid, which was prepared by Matumoto in 1944 (4, 5). Lithocholic acid has been shown to be a microbial metabolite of chenodeoxycholic acid in the rabbit as well as in other species (6-8). The presence of chenodeoxycholic acid in rabbit bile has not been conclusively demonstrated. However, Lindstedt2 has obtained evidence indicating that small amounts of chenodeoxycholic acid are formed from cholesterol in bile fistula rabbits. The mechanism of formation of crand &lagodeoxycholic acids is not known. The bile acids excreted in feces represent a complex mixture of microbial metabolites of the bilary bile acids. The nature of the fecal bile acids in rat and man has recently been studied in this laboratory (9,10) and by Heftmann et al. (11). Norman and Sjiivall(9) have shown that in rat the main microbial metabolites of cholic acid are 3a-hydroxy-12-keto-5&cholanic, deosycholic, and SLY, 12cr-dihydroxy-7-keto-5@cholanic acids. Lithocholic acid is the main product formed from chenodeoxycholic acid (7).
منابع مشابه
On the formation of hyodeoxycholic acid in the rat. Bile acids and steroids 154.
1. Lithocholic acid-24-l% was administered to rats and labeled hyodeoxycholic acid was isolated from feces and from bile collected after 3 days of intact enterohepatic circulation. Labeled 3a-hydroxy-6-keto-5P-cholanoic acid was isolated from feces. No labeled hyodeoxycholic acid was formed when lithocholic acid-24-l% was administered to bile fistula rats. One of the major metabolites in these ...
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