Insulin-like growth factor receptors in chicken liver membranes: binding properties, specificity, developmental pattern and evidence for a single receptor type.

摘要: Two distinct receptors for the insulin-like growth factors (IGF-I and IGF-II) have been identified in mammalian tissues, but so far only a receptor structurally related to type I has chicken embryonic tissues. This study was designed characterize binding sites IGF peptides liver microsomal membranes prepared from hatch 10 weeks of age which is period most rapid growth. Binding both human (h) IGF-I hIGF-II displaceable by either peptide exhibited similar pH, time temperature dependency. Human IGF-II more potent than hIGF-I competing iodinated ligands with half-maximum effective concentrations 3-5 micrograms/l 7-13 respectively. Porcine insulin also competitor. Affinity cross-linking studies, followed sodium dodecyl sulphate-polyacrylamide gel electrophoresis under reducing conditions demonstrated that were linked protein molecular weight about 130,000 Da characteristic alpha-subunit receptor. There no evidence presence II found mammals. Specific low on day hatch, increased threefold 3 remained high first life before returning lower steady state level up age.(ABSTRACT TRUNCATED AT 250 WORDS)