title: Distinct receptors for IGF-I, IGF-II, and insulin are present on bovine capillary endothelial cells and large vessel endothelial cells.
abstract: Endothelial cells were cultured from bovine fat capillaries, aortae and pulmonary arteries and their interactions with 125I-IGF-I, 125I-MSA (an IGF-II), 125I-insulin and the corresponding unlabeled hormones were evaluated. Each endothelial culture showed similar binding parameters. With 125I-insulin, unlabeled insulin competed with high affinity while IGF-I and MSA were approximately 1% as potent. With 125I-MSA, MSA was greater than or equal to IGF-I in potency and insulin did not compete for binding. Using 125I-IGF-I, IGF-I was greater than or equal to MSA whereas insulin decreased 125I-IGF-I binding by up to 72%. Exposing cells to anti-insulin receptor antibodies inhibited 125I-insulin binding by greater than 90%, did not change 125I-MSA binding, while 125I-IGF-I binding was decreased by 30-44%, suggesting overlapping antigenic determinants between IGF-I and insulin receptors that were not present on MSA receptors. We conclude that cultured capillary and large vessel endothelial cells have distinct receptors for insulin, IGF-I and MSA (IGF-II).
mesh_terms: D000818:Animals; D000906:Antibodies; D000936:Antigen-Antibody Complex; D001011:Aorta / Q000378:metabolism*; D002196:Capillaries / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D004727:Endothelium / Q000378:metabolism; D007328:Insulin / Q000378:metabolism; D007700:Kinetics; D010455:Peptides / Q000378:metabolism; D011651:Pulmonary Artery / Q000378:metabolism*; D011972:Receptor, Insulin / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism*; D017451:Receptors, Somatomedin; D013002:Somatomedins / Q000378:metabolism
chemical_list: D000906:Antibodies; D000936:Antigen-Antibody Complex; D007328:Insulin; D010455:Peptides; D011956:Receptors, Cell Surface; D017451:Receptors, Somatomedin; D013002:Somatomedins; D011972:Receptor, Insulin