title: Transepithelial transport of K+, NH4+, inorganic phosphate and water by hen (Gallus domesticus) lower intestine (colon and coprodeum) perfused luminally in vivo.
abstract: The colon and coprodeum of anaesthetised laying hens was perfused luminally with solutions of varying compositions to elucidate the influence of three levels of dietary Na+ and of luminal fluid composition on transport of electrolytes and water. Net rates of secretion of K+ and absorption of NH4+ were increased in response to dietary Na+ depletion and increased luminal Na+ concentrations, but these fluxes were linked to Na+ transport and no dietary or perfusion treatment effects could be detected on them independently of effects on Na+ flux. Similar results were found for Na+-linked water absorption from isosmotic perfusates. Serosal-mucosal net osmotic flow with Na+-free perfusates was significantly reduced by Na+-depletion, but no significant dietary effect could be detected on the serosal-mucosal osmotic permeability coefficient. The reflexion coefficient was effectively unity. Mucosal-serosal inorganic phosphate flux was small. The flux was independent of Na+ flux and dietary Na+ levels, and apparently facilitated by serosalmucosal osmotic flow. The data allowed determination of the absorption/secretion in coprodeum and colon of the ions investigated, as compared to the renal excretion rate.
mesh_terms: D000643:Ammonium Chloride / Q000378:metabolism; D000818:Animals; D001692:Biological Transport; D002645:Chickens / Q000378:metabolism*; D002988:Cloaca / Q000378:metabolism*; D003106:Colon / Q000378:metabolism*; D004032:Diet; D005260:Female; D010710:Phosphates / Q000378:metabolism; D011188:Potassium / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D012965:Sodium Chloride / Q000008:administration & dosage; D014882:Water-Electrolyte Balance
chemical_list: D010710:Phosphates; D000643:Ammonium Chloride; D012965:Sodium Chloride; D012964:Sodium; D011188:Potassium