THE DEVELOPMENT OF A RADIOIMMUNOASSAY FOR BOVINE NEUROPHYSIN

Abstract

SUMMARY A radioimmunoassay for bovine neurophysin is described. The assay has a lower limit of detection of approximately 0·5 ng/ml. Bovine neurophysin extracted and purified from acetone-dried posterior pituitary lobe powder was used for standardization, radio-iodination and immunization of rabbits. Some anti-neurophysin sera were also obtained from human subjects treated with Pitressin. Most of the antisera tested did not readily distinguish between the different neurophysin components isolated from bovine neurohypophysial tissue. The antisera cross-reacted with material extracted from whole pituitaries of a number of mammalian species, including man, pig, sheep, guinea-pig and rat, but not with the pituitary peptides from the cod or dogfish, or the egret. Other pituitary peptides, including oxytocin, vasopressin, corticotrophin, growth hormone and luteinizing hormone, did not interfere with the assay.