Homologous somatotropin radioreceptor assay utilizing recombinant bovine growth hormone

• Published in: Molecular and cellular endocrinology Vol. 38; no. 2; pp. 109 - 116
• Main Authors: Haro, Luis S., Collier, Robert J., Talamantes, Frank J.
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 01.01.1984; Elsevier
• Subjects: Animals; assays; Biological and medical sciences; bovine growth hormone; Cattle; Cell physiology; Fundamental and applied biological sciences. Psychology; Growth Hormone; growth hormone receptor; homologous hormone-receptor system; Hormonal regulation; Hydrogen-Ion Concentration; In Vitro Techniques; Iodine Radioisotopes; Kinetics; laboratory animals; Membranes - metabolism; Microsomes, Liver - metabolism; Molecular and cellular biology; Placental Lactogen - pharmacology; Prolactin - pharmacology; Proteins - metabolism; Radioligand Assay - methods; radioreceptor assay; Receptors, Cell Surface - metabolism; Receptors, Somatotropin; somatogenic; Temperature; Time Factors; bovine growth hormone; growth hormone receptor; somatogenic; radioreceptor assay; homologous hormone-receptor system; Protein hormone; Vertebrata; Mammalia; Radioreceptor assay; Purification; STH; Genetic engineering; Artiodactyla; Beef; Ungulata; Hormonal receptor
• ISSN: 0303-7207; 1872-8057
• DOI: 10.1016/0303-7207(84)90109-6

A homologous radioreceptor assay using recombinant bovine growth hormone and bovine liver membranes is described. The total specific binding of 125I-labeled recombinant bovine growth hormone to the 100000 × g pellet was 48% in 24 h at 25 °C. Hormone binding was partially reversible, with 40% of the radiolabeled hormone being irreversibly bound. The amount of specific binding varied with assay pH, with the optimum occurring at pH 7.8. Specific binding was temperature-dependent, with greater specific binding occurring at 25°C than at 5°C or 37°C during a 24 h period. Recombinant bovine growth hormone, human growth hormone, ovine growth hormone and recombinant porcine growth hormone competed effectively with 125I-labeled recombinant bovine growth hormone for binding sites, while bovine prolactin and ovine prolactin were needed in amounts 10 6-fold the concentration of recombinant bovine growth hormone to displace the radiolabeled hormone. Surprisingly, human placental lactogen did not displace the radiolabeled hormone.