title: Splanchnic net balance of oxygen and metabolites in response to a discontinuous mesenteric vein infusion of ammonium in sheep.
abstract: To simulate daily episodes of high absorption associated with the intake of diets with high N content, four wethers (42 ± 3.4 kg body weight), fitted with permanent catheters in the femoral artery and splanchnic vessels, were infused with 340 μmol into the mesenteric vein for 3 h, during the morning meal, over seven consecutive days. On the 7th day, mass transfers of , urea, glucose, lactate, ß-OH-butyrate and O2 were measured across portal-drained viscera (PDV), liver and splanchnic tissues during the last 90 min of the infusion. Measurements were repeated on the following day, at the same time, without the infusion. Plasma concentration in the portal vein (+332 μm; p = 0.006), portal absorption (+424 μmol/min; p < 0.001), liver uptake (+375 μmol/min; p = 0.003) and urea N production (+338 μmol/min; p = 0.059) were higher during infusion. Mass transfers of urea, glucose, lactate, ß-OH-butyrate and O2 across the PDV, and glucose, lactate, ß-OH-butyrate and O2 across the liver, were not altered by the infusion. Results suggest that a daily, discontinuous increase in portal flow during a meal stimulates liver removal and urea N production but does not significantly affect liver glucose production and O2 consumption in sheep.
authors.affiliation: Departamento de Fisiopatología, Facultad de Ciencias Veterinarias, Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA), Campus Universitario (7000) Tandil, Argentina.
authors.forename: M I
authors.initials: MI
authors.lastname: Recavarren
authors.forename: G D
authors.initials: GD
authors.lastname: Milano
mesh_terms: D000136:Acid-Base Equilibrium; D000641:Ammonia / Q000097:blood; D000818:Animals; D002254:Carbonates / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics / Q000494:pharmacology*; D007275:Injections, Intravenous; D008297:Male; D008642:Mesenteric Veins; D010100:Oxygen / Q000097:blood* / Q000378:metabolism; D012756:Sheep / Q000097:blood / Q000378:metabolism*; D013152:Splanchnic Circulation / Q000502:physiology*
chemical_list: D002254:Carbonates; D000641:Ammonia; C040502:ammonium carbonate; D010100:Oxygen