title: Identification and characterization of the insulin receptor of bovine retinal microvessels.
abstract: The presence of specific, high affinity receptors for insulin has been demonstrated in purified preparations of bovine retinal microvessels. The binding of [125I]insulin to isolated retinal microvessels was inhibited by unlabeled insulin, but not by other peptide hormones. Scatchard analysis of the [125I]insulin binding data gave a curvilinear plot similar to that exhibited by insulin receptors in known insulin-sensitive tissues such as adipocytes and hepatocytes. Binding of [125I]insulin to retinal microvessels, followed by covalent cross-linking of the bound ligand to the alpha-subunit of the insulin receptor with the bifunctional reagent disuccinimidyl suberate, yielded a prominent specific [125I]insulin-labeled band when analyzed by sodium dodecyl sulfate-gel electrophoresis followed by autoradiography, and this band had a mobility identical to that of the corresponding complex obtained with rat liver plasma membranes (mol wt, 125,000). These results demonstrate for the first time that the retinal microvasculature, a major site of pathological injury in diabetes mellitus, contains insulin receptors that are similar to those present in known insulin-sensitive tissues, such as liver, fat, and muscle.
mesh_terms: D000818:Animals; D001345:Autoradiography; D002196:Capillaries / Q000378:metabolism; D002417:Cattle; D003432:Cross-Linking Reagents; D007328:Insulin / Q000378:metabolism; D007457:Iodine Radioisotopes; D008970:Molecular Weight; D011972:Receptor, Insulin / Q000032:analysis / Q000378:metabolism*; D012160:Retina / Q000098:blood supply*; D013388:Succinimides; D013696:Temperature; D013997:Time Factors
chemical_list: D003432:Cross-Linking Reagents; D007328:Insulin; D007457:Iodine Radioisotopes; D013388:Succinimides; D011972:Receptor, Insulin; C019358:disuccinimidyl suberate