title: Insulin and IGF1 receptors in a model renal epithelium: receptor localization and characterization.
abstract: Insulin and IGF1 stimulate transepithelial Na+ transport in the urinary bladder of the toad Bufo marinus, a model renal epithelium. The signal transduction mechanisms for the natriferic action are unknown. Ultrastructural techniques were used to localize both receptors and ligands in the epithelium. Electron microscopy using gold-labelled anti-insulin or anti-IGF1 receptor antibodies demonstrated the majority of the insulin receptors were associated with the basolateral membrane while IGF1 receptors were found on basolateral and apical membranes. Both insulin and IGF1 receptors were found in endosomes and on the membranes surrounding subapical granules. In intact tissues incubated with iodinated IGF1 or insulin, both ligands were associated with the basolateral membrane. IGF1 was internalized to a greater extent than insulin and only IGF1 accumulated in cell nuclei.
authors.affiliation: Department of Medicine, Veterans Affairs Medical Center, Philadelphia, PA.
authors.forename: B L
authors.initials: BL
authors.lastname: Blazer-Yost
authors.forename: N
authors.initials: N
authors.lastname: Shah
authors.forename: L
authors.initials: L
authors.lastname: Jarett
authors.forename: M
authors.initials: M
authors.lastname: Cox
authors.forename: R M
authors.initials: RM
authors.lastname: Smith
mesh_terms: D000818:Animals; D002024:Bufo marinus; D004848:Epithelium / Q000378:metabolism / Q000648:ultrastructure; D005260:Female; D007150:Immunohistochemistry; D017136:Ion Transport; D007668:Kidney / Q000378:metabolism* / Q000648:ultrastructure; D016253:Microscopy, Immunoelectron; D009318:Natriuresis / Q000502:physiology; D017526:Receptor, IGF Type 1 / Q000378:metabolism*; D011972:Receptor, Insulin / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D012964:Sodium / Q000378:metabolism; D001743:Urinary Bladder / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D012964:Sodium; D017526:Receptor, IGF Type 1; D011972:Receptor, Insulin