{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,21]],"date-time":"2026-02-21T02:18:21Z","timestamp":1771640301023,"version":"3.50.1"},"reference-count":34,"publisher":"BMJ","issue":"5","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Gut"],"published-print":{"date-parts":[[1984,5]]},"abstract":"<jats:p>We have investigated whether acid-mediated bile acid precipitation, pancreatic enzyme inactivation, and fatty acid partitioning occur in health when intraluminal pH falls below 5. In order to assess lipolysis and aqueous solubilisation of lipid, we first developed a new technique for inactivating lipase in jejunal aspirate (acid inactivation), and showed it to be more effective and simpler than the established technique (heat inactivation). We then studied 14 healthy subjects, aspirating jejunal content for three hours after a liquid meal, and pooling according to pH. Eighteen per cent of the total aspirate was collected at pH less than 5 compared with 56% at pH greater than 6 (p less than 0.01). Forty eight per cent of the bile acids were precipitated at pH less than 5 compared with 18% at pH greater than 6 (p less than 0.01), leading to a reduction in aqueous phase bile acid concentration at low pH (2.1 mmol\/l at pH less than 5 vs 5.8 mmol\/l at pH greater than 6, p less than 0.01). Lipase activity was reduced at low pH (133 IU\/l at pH less than 5 vs 182 IU\/l at pH greater than 6, p less than 0.01), leading to reduced lipolysis at low pH (14% at pH less than 5 vs 32% at pH greater than 6, p less than 0.01). Aqueous phase lipid concentration was reduced at low pH (3.5 mmol\/l at pH less than 5 vs 12.5 mmol\/l at pH greater than 6, p less than 0.01). This reduction was less dependent on bile acid precipitation than on lipase inactivation and fatty acid partitioning. We conclude that intraluminal acidity influences aqueous solubilisation of bile acids and lipid in health.<\/jats:p>","DOI":"10.1136\/gut.25.5.491","type":"journal-article","created":{"date-parts":[[2007,9,7]],"date-time":"2007-09-07T20:55:35Z","timestamp":1189198535000},"page":"491-499","source":"Crossref","is-referenced-by-count":28,"title":["Effect of intrajejunal acidity on lipid digestion and aqueous solubilisation of bile acids and lipids in health, using a new simple method of lipase inactivation."],"prefix":"10.1136","volume":"25","author":[{"given":"P L","family":"Zentler-Munro","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"D R","family":"Fine","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"W J","family":"Fitzpatrick","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"T C","family":"Northfield","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"239","published-online":{"date-parts":[[1984,5,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"175","DOI":"10.1016\/0009-8981(75)90105-9","article-title":"Studies on the stability of pancreatic enzymes in duodenal fluid to storage temperature and pH","volume":"65","author":"Legg, E.F.; Spencer, A.M.","year":"1975","unstructured":"Legg EF, Spencer AM. Studies on the stability of pancreatic enzymes in duodenal fluid to storage temperature and pH. Clin Chim Acta 1975; 65: 175-9.","journal-title":"Clin Chim Acta"},{"key":"ref_2","first-page":"261","article-title":"Gastric inactivation of pancreatic supplements","volume":"116","author":"Heizer, W.D.; Cleaveland, C.R.; Iber, F.L.","year":"1965","unstructured":"Heizer WD, Cleaveland CR, Iber FL. Gastric inactivation of pancreatic supplements. Bull Johns Hopkins Hosp 1965; 116: 261-70.","journal-title":"Bull Johns Hopkins Hosp"},{"key":"ref_3","first-page":"289","article-title":"The physical chemistry of cholanic acids","volume-title":"The bile acids","volume":"1","author":"Small, D.M.","year":"1971","unstructured":"Small DM. The physical chemistry of cholanic acids. In: Nair PP, Kritchevsky D, eds. The bile acids, vol. 1 (Chemistry). 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