Specific, high affinity receptors for insulin-like growth factor II in the rat kidney glomerulus

• Published in: Endocrinology (Philadelphia) Vol. 123; no. 2; p. 774
• Main Authors: Haskell, J F, Pillion, D J, Meezan, E
• Format: Journal Article
• Language: English
• Published: United States 01.08.1988
• Subjects: Animals; Binding, Competitive; Cell Membrane - metabolism; Cross-Linking Reagents; Electrophoresis, Polyacrylamide Gel; Immunoenzyme Techniques; Insulin-Like Growth Factor II - metabolism; Iodine Radioisotopes; Kidney Glomerulus - metabolism; Male; Molecular Weight; Rats; Rats, Inbred Strains; Receptor, Insulin - metabolism; Receptors, Somatomedin; Somatomedins - metabolism; Succinimides
• ISSN: 0013-7227
• DOI: 10.1210/endo-123-2-774

Rat renal glomeruli were isolated by a technique involving kidney perfusion with a solution containing magnetic iron oxide particles, followed by homogenization, sieving, and concentration over a strong magnet. Isolated glomeruli were treated with 1% Triton X-100 to solubilize plasma membrane components, while insoluble basement membrane components were removed by centrifugation. [125I]Insulin-like growth factor II (IGF-II) binding to this preparation was competitively inhibited by increasing amounts of unlabeled IGF-II, with 50% inhibition at an IGF-II concentration of 1 ng/ml. [125I]IGF-II was covalently cross-linked with disuccinimidyl suberate to its receptor in rat renal glomeruli and a specific high mol wt (255,000) band could be identified on autoradiograms of dodecyl sulfate-polyacrylamide gels. [125I]IGF-II binding and cross-linking to this band was inhibited by a polyclonal antibody against the type II IGF receptor. These results demonstrate for the first time that the isolated rat renal glomerulus contains a high affinity receptor for IGF-II.