{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,6]],"date-time":"2026-10-06T12:14:49Z","timestamp":1791288889918,"version":"4.3.0"},"reference-count":38,"publisher":"BMJ","issue":"6","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Gut"],"accepted":{"date-parts":[[2001,3,15]]},"published-print":{"date-parts":[[2001,12,1]]},"abstract":"<jats:sec>\n                  <jats:title>BACKGROUND<\/jats:title>\n                  <jats:p>Deoxycholic acid (DCA), implicated in the pathogenesis of gall stones and colorectal cancer, is mainly formed by bacterial deconjugation (cholylglycine hydrolase (CGH)) and 7\u03b1-dehydroxylation (7\u03b1-dehydroxylase (7\u03b1-DH)) of conjugated cholic acid (CA) in the caecum\/proximal colon. Despite this, most previous studies of CGH and 7\u03b1-DH have been in faeces rather than in caecal contents. In bacteria, CA increases 7\u03b1-DH activity by substrate-enzyme induction but little is known about CA concentrations or CA\/7\u03b1-DH induction in the human colon.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>AIMS AND METHODS<\/jats:title>\n                  <jats:p>Therefore, in fresh \u201cfaeces\u201d, and in caecal aspirates obtained during colonoscopy from 20 patients, we: (i) compared the activities of CGH and 7\u03b1-DH, (ii) measured 7\u03b1-DH in patients with \u201clow\u201d and \u201chigh\u201d percentages of DCA in fasting serum (less than and greater than the median), (iii) studied CA concentrations in the right and left halves of the colon, and examined the relationships between (iv) 7\u03b1-DH activity and CA concentration in caecal samples (evidence of substrate-enzyme induction), and (v) 7\u03b1-DH and per cent DCA in serum.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>RESULTS<\/jats:title>\n                  <jats:p>Although mean CGH activity in the proximal colon (18.3 (SEM 4.40) \u00d710<jats:sup>\u22122<\/jats:sup> U\/mg protein) was comparable with that in \u201cfaeces\u201d (16.0 (4.10) \u00d710<jats:sup>\u2212 2<\/jats:sup> U\/mg protein) , mean 7\u03b1-DH in the caecum (8.54 (1.08) \u00d710<jats:sup>-4<\/jats:sup> U\/mg protein) was higher (p&lt;0.05) than that in the left colon (5.72 (0.85) \u00d710<jats:sup>-4<\/jats:sup> U\/mg protein). At both sites, 7\u03b1-DH was significantly greater in the \u201chigh\u201d than in the \u201clow\u201d serum DCA subgroups. CA concentrations in the right colon (0.94 (0.08) \u03bcmol\/ml) were higher than those in the left (0.09 (0.03) \u03bcmol\/ml; p&lt;0.001) while in the caecum (but not in the faeces) there was a weak (<jats:italic>r<\/jats:italic>=0.58) but significant (p&lt;0.005) linear relationship between 7\u03b1-DH and CA concentration. At both sites, 7\u03b1-DH was linearly related (p&lt;0.005) to per cent DCA in serum.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>INTERPRETATION\/SUMMARY<\/jats:title>\n                  <jats:p>These results: (i) confirm that there are marked regional differences in bile acid metabolism between the right and left halves of the colon, (ii) suggest that caecal and faecal 7\u03b1-DH influence per cent DCA in serum (and, by inference, in bile), and (iii) show that the substrate CA induces the enzyme 7\u03b1-DH in the caecum.<\/jats:p>\n               <\/jats:sec>","DOI":"10.1136\/gut.49.6.835","type":"journal-article","created":{"date-parts":[[2002,7,27]],"date-time":"2002-07-27T06:32:19Z","timestamp":1027751539000},"page":"835-842","source":"Crossref","is-referenced-by-count":67,"title":["Bile acid metabolism by fresh human colonic contents: a comparison of caecal versus faecal samples"],"prefix":"10.1136","volume":"49","author":[{"given":"L A","family":"Thomas","sequence":"first","affiliation":[{"name":"aGastroenterology Unit, Guy's Hospital Campus, UMDS, London, UK, \n\nbMicrobiology Department, St Thomas' Hospital Campus, UMDS, London, UK, \n\ncDepartments of Microbiology and Medicine, Virginia Commonwealth University, Richmond, Virginia, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"M J","family":"Veysey","sequence":"additional","affiliation":[{"name":"aGastroenterology Unit, Guy's Hospital Campus, UMDS, London, UK, \n\nbMicrobiology Department, St Thomas' Hospital Campus, UMDS, London, UK, \n\ncDepartments of Microbiology and Medicine, Virginia Commonwealth University, Richmond, Virginia, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"G","family":"French","sequence":"additional","affiliation":[{"name":"aGastroenterology Unit, Guy's Hospital Campus, UMDS, London, UK, \n\nbMicrobiology Department, St Thomas' Hospital Campus, UMDS, London, UK, \n\ncDepartments of Microbiology and Medicine, Virginia Commonwealth University, Richmond, Virginia, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"P B","family":"Hylemon","sequence":"additional","affiliation":[{"name":"aGastroenterology Unit, Guy's Hospital Campus, UMDS, London, UK, \n\nbMicrobiology Department, St Thomas' Hospital Campus, UMDS, London, UK, \n\ncDepartments of Microbiology and Medicine, Virginia Commonwealth University, Richmond, Virginia, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"G M","family":"Murphy","sequence":"additional","affiliation":[{"name":"aGastroenterology Unit, Guy's Hospital Campus, UMDS, London, UK, \n\nbMicrobiology Department, St Thomas' Hospital Campus, UMDS, London, UK, \n\ncDepartments of Microbiology and Medicine, Virginia Commonwealth University, Richmond, Virginia, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"R H","family":"Dowling","sequence":"additional","affiliation":[{"name":"aGastroenterology Unit, Guy's Hospital Campus, UMDS, London, UK, \n\nbMicrobiology Department, St Thomas' Hospital Campus, UMDS, London, UK, \n\ncDepartments of Microbiology and Medicine, Virginia Commonwealth University, Richmond, Virginia, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"239","published-online":{"date-parts":[[2001,12,1]]},"reference":[{"key":"2025090713441065000_49.6.835.1","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1016\/S0021-9258(18)96311-8","article-title":"The enzymatic cleavage of the carbon-nitrogen bond in 3\u03b1,7\u03b1,12\u03b1-trihydroxy-5\u03b2-cholan-24-oyl glycine.","volume":"243","author":"Nair","year":"1967","journal-title":"J Biol Chem"},{"key":"2025090713441065000_49.6.835.2","doi-asserted-by":"crossref","first-page":"325","DOI":"10.1016\/S0022-2275(20)40615-7","article-title":"7\u03b1 dehydroxylation of cholic acid and chenodeoxycholic acid by Clostridium leptum.","volume":"20","author":"Stellwag","year":"1979","journal-title":"J Lipid Res"},{"key":"2025090713441065000_49.6.835.3","doi-asserted-by":"publisher","DOI":"10.1136\/gut.9.1.22"},{"key":"2025090713441065000_49.6.835.4","doi-asserted-by":"publisher","DOI":"10.1136\/gut.10.7.575"},{"key":"2025090713441065000_49.6.835.5","doi-asserted-by":"publisher","DOI":"10.1084\/jem.123.2.413"},{"key":"2025090713441065000_49.6.835.6","doi-asserted-by":"crossref","first-page":"257","DOI":"10.1007\/BF02602827","article-title":"Prevalence of oxygen intolerant micro-organisms in primary bile acid 7\u03b1 dehydroxylating mouse intestinal microflora.","volume":"4","author":"Ferrari","year":"1980","journal-title":"Curr Microbiol"},{"key":"2025090713441065000_49.6.835.7","doi-asserted-by":"crossref","first-page":"1185","DOI":"10.1128\/aem.63.3.1185-1188.1997","article-title":"Assessment of faecal bacteria with bile acid 7\u03b1 dehydroxylase activity for the presence of bai-like genes.","volume":"63","author":"Doerner","year":"1997","journal-title":"Appl Environ Microbiol"},{"key":"2025090713441065000_49.6.835.8","doi-asserted-by":"publisher","DOI":"10.1016\/S0016-5085(96)70024-0"},{"key":"2025090713441065000_49.6.835.9","first-page":"421","article-title":"The microflora of the human ileum and intra-abdominal colon: Results of direct needle aspiration at surgery and evaluation of the technique.","volume":"79","author":"Bentley","year":"1972","journal-title":"J Lab Clin Med"},{"key":"2025090713441065000_49.6.835.10","doi-asserted-by":"publisher","DOI":"10.1136\/gut.29.8.1035"},{"key":"2025090713441065000_49.6.835.11","doi-asserted-by":"publisher","DOI":"10.1111\/j.1365-2036.1989.tb00254.x"},{"key":"2025090713441065000_49.6.835.12","doi-asserted-by":"crossref","first-page":"13","DOI":"10.1097\/00008469-199202000-00004","article-title":"Faecal steroids and colorectal cancer: the effect of lactulose on faecal bacterial metabolism in a continuous culture model of the large intestine.","volume":"1","author":"Fadden","year":"1992","journal-title":"Eur J Cancer Prev"},{"key":"2025090713441065000_49.6.835.13","doi-asserted-by":"publisher","DOI":"10.1016\/0039-128X(80)90115-4"},{"key":"2025090713441065000_49.6.835.14","doi-asserted-by":"crossref","first-page":"467","DOI":"10.3181\/00379727-94-22981","article-title":"Turnover and nature of faecal bile acids in germfree and infected rats fed cholic acid-24\u201314C.","volume":"94","author":"Gustafsson","year":"1957","journal-title":"Proc Soc Exp Biol Med"},{"key":"2025090713441065000_49.6.835.15","doi-asserted-by":"publisher","DOI":"10.1053\/gast.2000.16495"},{"key":"2025090713441065000_49.6.835.16","unstructured":"Murray RK Granner DK Mayer PA (1988) Harper's Biochemistry (Appleton and Lange, New York), 2nd edn. pp 55\u201356."},{"key":"2025090713441065000_49.6.835.17","doi-asserted-by":"publisher","DOI":"10.1016\/S0009-8981(97)00169-1"},{"key":"2025090713441065000_49.6.835.18","doi-asserted-by":"publisher","DOI":"10.1002\/(SICI)1099-0801(199601)10:1<1::AID-BMC536>3.0.CO;2-3"},{"key":"2025090713441065000_49.6.835.19","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1016\/S0022-2275(20)40358-X","article-title":"Thin layer chromatography of bile acids.","volume":"4","author":"Eneroth","year":"1963","journal-title":"J Lipid Res"},{"key":"2025090713441065000_49.6.835.20","doi-asserted-by":"publisher","DOI":"10.1016\/0009-8981(70)90078-1"},{"key":"2025090713441065000_49.6.835.21","doi-asserted-by":"publisher","DOI":"10.1016\/S0021-9673(01)94498-X"},{"key":"2025090713441065000_49.6.835.22","doi-asserted-by":"crossref","first-page":"1647","DOI":"10.1016\/S0022-2275(20)38248-1","article-title":"Determination of plasma bile acids by capillary gas-liquid chromatography-electron capture negative chemical ionisation mass fragmentography.","volume":"30","author":"Stellaard","year":"1989","journal-title":"J Lipid Res"},{"key":"2025090713441065000_49.6.835.23","doi-asserted-by":"publisher","DOI":"10.1016\/0009-8981(83)90070-0"},{"key":"2025090713441065000_49.6.835.24","doi-asserted-by":"publisher","DOI":"10.1007\/BF02239591"},{"key":"2025090713441065000_49.6.835.25","doi-asserted-by":"publisher","DOI":"10.1128\/jb.174.7.2065-2071.1992"},{"key":"2025090713441065000_49.6.835.26","doi-asserted-by":"crossref","first-page":"2070","DOI":"10.1172\/JCI105892","article-title":"Absorption of bile acids from the large bowel in man.","volume":"47","author":"Samuel","year":"1968","journal-title":"J Clin Invest"},{"key":"2025090713441065000_49.6.835.27","doi-asserted-by":"crossref","first-page":"481","DOI":"10.1016\/S0016-5085(19)34363-X","article-title":"Distribution of disaccharidase activity in the small bowel of normal and lactase deficient subjects.","volume":"51","author":"Newcomer","year":"1966","journal-title":"Gastroenterology"},{"key":"2025090713441065000_49.6.835.28","doi-asserted-by":"crossref","first-page":"1377","DOI":"10.1016\/S0016-5085(19)31517-3","article-title":"Individual bile acids in portal venous and systemic blood serum in fasting man.","volume":"73","author":"Ahlberg","year":"1977","journal-title":"Gastroenterology"},{"key":"2025090713441065000_49.6.835.29","doi-asserted-by":"crossref","first-page":"1063","DOI":"10.1016\/S0140-6736(78)91800-7","article-title":"Colonic bacterial activity, biliary cholesterol saturation and pathogenesis of gallstones.","volume":"2","author":"Low-Beer","year":"1978","journal-title":"Lancet"},{"key":"2025090713441065000_49.6.835.30","doi-asserted-by":"publisher","DOI":"10.1136\/gut.49.6.828"},{"key":"2025090713441065000_49.6.835.31","doi-asserted-by":"publisher","DOI":"10.1136\/gut.27.5.550"},{"key":"2025090713441065000_49.6.835.32","doi-asserted-by":"publisher","DOI":"10.1111\/j.1365-2362.1988.tb01166.x"},{"key":"2025090713441065000_49.6.835.33","doi-asserted-by":"crossref","first-page":"1018","DOI":"10.1136\/bmj.282.6269.1018","article-title":"Do colonic bacteria contribute to cholesterol gallstone formation? Effects of lactulose on bile.","volume":"282","author":"Thornton","year":"1981","journal-title":"BMJ"},{"key":"2025090713441065000_49.6.835.34","doi-asserted-by":"publisher","DOI":"10.1136\/gut.14.7.513"},{"key":"2025090713441065000_49.6.835.35","doi-asserted-by":"crossref","first-page":"1454","DOI":"10.1016\/0016-5085(81)90257-2","article-title":"Factors in the mechanism of diarrhea in bile acid malabsorption: fecal pH\u2014a key determinant.","volume":"80","author":"McJunkin","year":"1981","journal-title":"Gastroenterology"},{"key":"2025090713441065000_49.6.835.36","doi-asserted-by":"crossref","first-page":"955","DOI":"10.1016\/0016-5085(93)90930-B","article-title":"Deoxycholic acid metabolism in patients with adenomas.","volume":"105","author":"Nagengast","year":"1993","journal-title":"Gastroenterology"},{"key":"2025090713441065000_49.6.835.37","doi-asserted-by":"publisher","DOI":"10.1111\/j.1572-0241.1998.00470.x"},{"key":"2025090713441065000_49.6.835.38","doi-asserted-by":"publisher","DOI":"10.1053\/gast.2001.28015"}],"container-title":["Gut"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.1136\/gut.49.6.835","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,9,7]],"date-time":"2025-09-07T20:44:19Z","timestamp":1757277859000},"score":1,"resource":{"primary":{"URL":"https:\/\/gut.bmj.com\/lookup\/doi\/10.1136\/gut.49.6.835"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2001,12,1]]},"references-count":38,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2001,12,1]]},"published-print":{"date-parts":[[2001,12,1]]}},"alternative-id":["10.1136\/gut.49.6.835"],"URL":"https:\/\/doi.org\/10.1136\/gut.49.6.835","relation":{},"ISSN":["0017-5749","1468-3288"],"issn-type":[{"value":"0017-5749","type":"print"},{"value":"1468-3288","type":"electronic"}],"subject":[],"published":{"date-parts":[[2001,12,1]]}}}