A RADIOIMMUNOASSAY FOR RECOMBINANT-DERIVED CHICKEN PROLACTIN SUITABLEFOR THE MEASUREMENT OF PROLACTIN IN OTHER AVIAN SPECIES

A homologous radioimmunoassay for chicken prolactin is described. The assay is based on recombinant-derived chicken prolactin that has been used to raise an antibody and produce I-125-labeled tracer and assay s tandards. The radioimmunoassay measures a minimum of 0.03 +/- 0.01 ng of the recombinant prolactin with 50% displacement of binding by 0.6 /- 0.1 ng. Chicken plasma and pituitary immunoreactivity dilute in par allel with the standard curve. The mean (+/- SE) concentrations of pla sma prolactin were 12.1 +/- 1.5, 433.2 +/- 5.5, and 1609.8 +/- 18.5 ng /ml in out-of-lay, laying, and incubating bantam hens, respectively. T he binding of recombinant prolactin was not displaced by extracts of n eural lobe or plasma from a hypophysectomized hen. Plasma prolactin co ncentrations were increased after intravenous administration of chicke n vasoactive intestinal polypeptide or quipazine, a 5-HT agonist. The assay measures immunoreactive prolactin in other birds. Plasma from qu ail, turkey, great tit, and wryneck displaced the I-125-labeled prolac tin tracer parallel to the standard curve. Starling, ring dove, and pe nguin plasma displaced the binding in a nonparallel manner. (C) 1994 A cademic Press, Inc.