title: Down-regulation of insulin receptors is related to insulin internalization.
abstract: In the present study, we have tested the influence of inhibition of endocytosis by hypertonic medium on the regulation of cell surface insulin receptors. We show that active internalization of 125I-insulin is markedly inhibited by hypertonic media and that, in parallel, cell surface invaginations are significantly diminished. These two events are accompanied by a marked inhibition of cell surface insulin receptor down-regulation. These data provide further strong evidence that receptor-mediated endocytosis is the major mechanism by which insulin receptors are regulated at the surface of target cells.
authors.affiliation: Institute of Histology and Embryology, University of Geneva Medical Center, Switzerland.
authors.forename: D
authors.initials: D
authors.lastname: Geiger
authors.forename: J L
authors.initials: JL
authors.lastname: Carpentier
authors.forename: P
authors.initials: P
authors.lastname: Gorden
authors.forename: L
authors.initials: L
authors.lastname: Orci
mesh_terms: D002460:Cell Line; D003470:Culture Media / Q000494:pharmacology; D015536:Down-Regulation / Q000187:drug effects / Q000502:physiology*; D004705:Endocytosis / Q000187:drug effects / Q000502:physiology; D006801:Humans; D007038:Hypotonic Solutions; D007328:Insulin / Q000378:metabolism*; D007457:Iodine Radioisotopes; D015479:Leukemia, Myelomonocytic, Acute / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology; D008214:Lymphocytes / Q000473:pathology / Q000648:ultrastructure*; D008565:Membrane Proteins / Q000502:physiology; D008854:Microscopy, Electron; D011972:Receptor, Insulin / Q000378:metabolism / Q000502:physiology*
chemical_list: D003470:Culture Media; D007038:Hypotonic Solutions; D007328:Insulin; D007457:Iodine Radioisotopes; D008565:Membrane Proteins; D011972:Receptor, Insulin