title: Plasma concentrations of somatomedin-C in hypophysectomized, dwarf and intact growing domestic fowl as determined by heterologous radioimmunoassay.
abstract: The application of a human somatomedin-C radioimmunoassay for the determination of somatomedin-C in chicken plasma has been examined. Parallel inhibition of binding of 125I-labelled somatomedin-C to antisera raised against somatomedin-C was observed with acid-treated human and chicken plasma. The concentration of immunoreactive (IR)-somatomedin-C in the plasma of the domestic fowl appears to be GH dependent. Plasma concentrations of IR-somatomedin-C were reduced after hypophysectomy and partially restored by replacement therapy with chicken GH. The age/development pattern of circulating concentrations of IR-somatomedin-C has been determined in normal and dwarf strains of domestic fowl. Increases in the plasma concentration of IR-somatomedin-C were observed between 1 and 6 weeks of age in control male domestic fowl of either heavy (broiler type) or light (White Leghorn) strains. Thereafter, the plasma concentrations of IR-somatomedin-C remained constant in the heavy strain birds but declined in White Leghorn chicks. Plasma concentrations of IR-somatomedin-C were reduced in sex-linked dwarf chickens, in both light and heavy strains of fowl, but were unaffected in autosomal dwarf chickens.
mesh_terms: D000818:Animals; D001835:Body Weight; D002645:Chickens; D004393:Dwarfism, Pituitary / Q000097:blood*; D013006:Growth Hormone / Q000494:pharmacology; D007016:Hypophysectomy; D007334:Insulin-Like Growth Factor I; D008297:Male; D010902:Pituitary Gland / Q000187:drug effects / Q000502:physiology*; D011863:Radioimmunoassay; D013002:Somatomedins / Q000097:blood*
chemical_list: D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone