Gastrointestinal urease in man. II. Urea hydrolysis and ammonia absorption in upper and lower gut lumen and the effect of neomycin.

Evans, William B.; Aoyagi, Toshio; Summerskill, W.H.J.

doi:10.1136/gut.7.6.635

Cited by 21 publications

(8 citation statements)

References 27 publications

(26 reference statements)

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“…However, others have interpreted evidence from several species, including man, to indicate only a bacterial origin of urease in the gut (Kornberg and Davies, 1955;Thomson and Visek, 1963). The results of the present studies and those from a concurrent investigation (Evans, Aoyagi, and Summerskill, 1966) are consistent with contributions from both bacteria and the mucosa to gastrointestinal tract urease activity in man. Values from mucosal homogenates were highest in the stomach and upper part of the small intestine and presumably reflected largely mucosal enzyme, since bacteria are believed normally to be scanty or absent (Cregan, Dunlop, and Hayward, 1953;Cregan and Hayward, 1953;Goldstein, Wirts, and Josephs, 1962;Shiner, Waters, and Gray, 1963) in these areas.…”

Section: Discussionsupporting

confidence: 82%

Gastrointestinal urease in man. I. Activity of mucosal urease.

Aoyagi¹,

Engström²,

Evans³

et al. 1966

Gut

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Section: Discussionsupporting

confidence: 82%

Gastrointestinal urease in man. I. Activity of mucosal urease.

Aoyagi¹,

Engström²,

Evans³

et al. 1966

Gut

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“…Studies in man with antibiotics confirm that urease is largely bacterial in origin but are more specific in localizing its site to the large intestine (Aoyagi et ul., 1966;Evans et al, 1966). This suggests that urea Walser & bod en lo^ ( All subjects were studied on uncontrolled normal diets.…”

Section: Discussionmentioning

confidence: 99%

The Role of the Colon in Urea Metabolism in Man

et al. 1976

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1. The urea content of ileostomy effluent has been measured by the urease method as an indirect estimate of the urea concentration in the lumen of the normal ileum. 2. The plasma disappearance of intravenously administered[14C]urea was used to study intestinal urea breakdown. Normal subjects on high and low protein diets and patients with either excised (i.e. with ileostomies) or excluded colons were studied. 3. The 24 h intestinal urea breakdown was considerably greater than the quantity of urea estimated to be entering the colon from the ileum and across the colonic mucosa. 4. Intestinal urea breakdown increased with increase in dietary protein and decreased with, but was not abolished by, exclusion or excision of the colon. 5. Our results suggest that the colonic lumen is not the only site of intestinal ureolysis and that significant quantities of urea must be broken down either at a juxtamucosal site or in the ileum.

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“…The major source of colonic urease is the gut bacterial flora. Treatment of patients with neomycin or other antibiotics reduces the faecal urease activity (Evans, Aoyagi, and Summerskill, 1966) and germ-free animals fail to catabolize urea to any significant extent (Levenson, Crowley, Horowitz, and Malm, 1959). Interestingly, it appears that it is the mucosal flora that is important in urea metabolism rather than the luminal flora.…”

Section: Ammonia Metabolismmentioning

confidence: 99%