title: Renal tubular cells are potential targets for epidermal growth factor.
abstract: Epidermal growth factor (EGF) is a potent polypeptide mitogen with various receptor-mediated growth effects on cells from the skin, breast, and gastrointestinal tract. Recent studies indicate that EGF is produced in the kidney and is excreted in the urine, but the biological significance of renal EGF is uncertain. We demonstrate in vitro mitogenicity of EGF for LLC-PK1 cells, a tubular epithelial cell line derived from pig kidney cortex. Furthermore, when subconfluent monolayers of LLC-PK1 cells are exposed to EGF for 24 h, sodium-dependent phosphate transport is stimulated (209-410% of control). These cells possess EGF-specific high-affinity binding sites at their surface (Kd 300-700 pM) but cannot synthesize the growth factor. EGF binding sites are not a peculiarity of the LLC-PK1 cell line, since similar sites are present on MDCK cells (derived from dog kidney distal tubule or collecting duct), primary cultures of mouse proximal tubular cells, and freshly prepared membrane fractions from mouse kidney. Cortical basolateral membranes are highly enriched in EGF binding sites, whereas EGF binding by brush-border membrane fractions is minimal and is compatible with contamination.
authors.affiliation: Department of Pediatrics, McGill University-Montreal Children's Hospital Research Institute, Quebec, Canada.
authors.forename: P R
authors.initials: PR
authors.lastname: Goodyer
authors.forename: Z
authors.initials: Z
authors.lastname: Kachra
authors.forename: C
authors.initials: C
authors.lastname: Bell
authors.forename: R
authors.initials: R
authors.lastname: Rozen
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D004815:Epidermal Growth Factor / Q000378:metabolism / Q000494:pharmacology*; D066246:ErbB Receptors / Q000378:metabolism; D007684:Kidney Tubules / Q000166:cytology* / Q000187:drug effects; D007700:Kinetics; D008871:Microvilli / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism; D012964:Sodium / Q000494:pharmacology
chemical_list: D010710:Phosphates; D004815:Epidermal Growth Factor; D012964:Sodium; D066246:ErbB Receptors