title: Effect of external potassium concentration on potassium uptake and potassium permeability of chicken enterocytes.
abstract: 1. The effects of external potassium concentration on potassium uptake and potassium permeability have been investigated in isolated chicken enterocytes. 2. Ouabain-sensitive K+ uptake exhibited simple saturation kinetics with an apparent affinity constant, KT, of approximately, 1 mM K+. In the presence of ouabain, K+ uptake relates linearly with its external concentration, and the apparent diffusion constant, KD, was 1.3 nmol mg-1 protein mM-1 min-1. 3. Membrane potential, evaluated from the transmembrane TPP+ distribution ratio, was lower than the potassium equilibrium potential. 4. Estimated potassium permeability is decreased by low external potassium concentration and unaffected by high external potassium concentration.
authors.affiliation: Departamento de Fisiología y Biología Animal, Facultad de Farmacia, Universidad de Sevilla, Spain.
authors.forename: M C
authors.initials: MC
authors.lastname: Montero
authors.forename: A
authors.initials: A
authors.lastname: Ilundáin
mesh_terms: D000818:Animals; D002463:Cell Membrane Permeability / Q000187:drug effects*; D002478:Cells, Cultured; D002645:Chickens; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000166:cytology* / Q000187:drug effects; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D010042:Ouabain / Q000494:pharmacology; D011188:Potassium / Q000097:blood / Q000378:metabolism / Q000494:pharmacology*; D012414:Rubidium Radioisotopes; D013942:Thymine Nucleotides / Q000378:metabolism
chemical_list: D012414:Rubidium Radioisotopes; D013942:Thymine Nucleotides; D010042:Ouabain; C024157:thymidine 5'-triphosphate; D011188:Potassium