title: Receptor-mediated degradation of insulin in isolated rat adipocytes. Formation of a degradation product slightly smaller than insulin.
abstract: More than 90% of the radioactivity associated with isolated rat adipocytes incubated with [TyrA14-125I]monoiodoinsulin represented at steady state iodoinsulin possessing full binding affinity. In contrast, about half of the radioactivity dissociating from the cells was [125I]monoiodotyrosine. The other half was of a molecular size similar to that of iodoinsulin as judged from gel-filtration chromatography. However, the descending limb of the 'insulin' peak (i.e., the smaller molecules) possessed a reduced binding activity compared with native iodoinsulin, material from the ascending limb, or a similar fraction isolated from dissociation medium from IM-9 lymphocytes, a cell type devoid of receptor-mediated insulin degradation. The cells, thus, release an intermediary degradation product.
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism*; D000818:Animals; D002850:Chromatography, Gel; D007328:Insulin / Q000031:analogs & derivatives / Q000378:metabolism*; D007457:Iodine Radioisotopes; D008970:Molecular Weight; D007470:Monoiodotyrosine / Q000378:metabolism; D051381:Rats; D011972:Receptor, Insulin / Q000378:metabolism*
chemical_list: D007328:Insulin; D007457:Iodine Radioisotopes; C008147:insulin, iodo-; D011972:Receptor, Insulin; D007470:Monoiodotyrosine