Down-regulation of insulin receptors is related to insulin internalization.
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.
Geiger
D
D
Institute of Histology and Embryology, University of Geneva Medical Center, Switzerland.
Carpentier
J L
JL
Gorden
P
P
Orci
L
L
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*
D003470:Culture Media; D007038:Hypotonic Solutions; D007328:Insulin; D007457:Iodine Radioisotopes; D008565:Membrane Proteins; D011972:Receptor, Insulin