title: Binding of epidermal growth factor to receptors in preparations of enriched porcine parietal cells and inhibition of aminopyrine uptake.
abstract: Preparations of isolated porcine gastric cells, enriched in parietal cells, were used to study binding of epidermal growth factor (EGF) to receptors and subsequent inhibition of [14C]aminopyrine uptake. EGF in concentrations from 10(-10) to 10(-7) M inhibited aminopyrine uptake stimulated by 10(-5) M histamine with an IC50 of 3 x 10(-10) M. [125]EGF bound in a saturable and specific manner to sites on cells in preparations containing 40-90% parietal cells. Mean apparent dissociation constant for the sites was 1.6 x 10(-9) M, with an average number of approximately 20,000 sites per cell. Endocytosis of ligand by parietal cells was limited, amounting to 10-20% of bound EGF after 1 h of incubation at 37 degrees C. Occupation of a fraction of the receptors caused a maximal reduction by 40% of aminopyrine uptake in histamine-stimulated cells, suggesting the occurrence of spare receptors. The results indicate the existence of specific receptors for EGF on porcine parietal cells exerting a regulatory influence on acid secretion.
authors.affiliation: Pharmacologic Division, Medical Products Agency, Uppsala, Sweden.
authors.forename: L
authors.initials: L
authors.lastname: Sjödin
authors.forename: H G
authors.initials: HG
authors.lastname: Dahlén
authors.forename: E
authors.initials: E
authors.lastname: Viitanen
mesh_terms: D000632:Aminopyrine / Q000493:pharmacokinetics*; D000818:Animals; D004815:Epidermal Growth Factor / Q000378:metabolism* / Q000494:pharmacology; D066246:ErbB Receptors / Q000378:metabolism*; D006632:Histamine / Q000494:pharmacology; D066298:In Vitro Techniques; D007457:Iodine Radioisotopes; D010295:Parietal Cells, Gastric / Q000378:metabolism*; D013552:Swine
chemical_list: D007457:Iodine Radioisotopes; D000632:Aminopyrine; D004815:Epidermal Growth Factor; D006632:Histamine; D066246:ErbB Receptors