title: The mechanism of passage of endogenous urea through the rumen wall and the role of ureolytic epithelial bacteria in the urea flux.
abstract: 1. The rumen urea concentration in gnotobiotic lambs lacking ureolytic bacteria was equal to that of blood. 2. Bacterial urease (EC 3.5.1.5) activity in sheep fed by intraruminal and intra-abomasal infusion was inversely related to rumen ammonia concentration. 3. A model is proposed for the facilitation and control of urea flux by wall-found ureolytic bacteria.
mesh_terms: D000641:Ammonia / Q000378:metabolism; D000818:Animals; D001419:Bacteria / Q000378:metabolism*; D005750:Gastric Juice / Q000378:metabolism; D005856:Germ-Free Life; D007441:Intubation, Gastrointestinal; D012417:Rumen / Q000382:microbiology*; D012756:Sheep; D013279:Stomach, Ruminant; D014508:Urea / Q000378:metabolism*; D014510:Urease / Q000378:metabolism*
chemical_list: D000641:Ammonia; D014508:Urea; D014510:Urease