Using micro-quantity of chloramine T in chicken pro-latin labelling and radioimmunoassay

A radioimmunoassay was developed for measurement of chicken plasma prolactin. The assay used chPRL(AFP-10328B) as reference standard, chPRL(AFP-4444B) as the radio labelled ligand, rabbit anti-chicken PRL (AFP-151040789) as first antibody, and donkey anti-rabbit IgG antiserum as second antibody. For iodide ratio labelling of chicken PRL, a modified chloramine T method which reduced the amount of chloramine T and omitted sodium metabisulfite, and produced the labelled hormone with a specific activity of 29μCi/μg was used. The assay sensitivity was 0.34 ng/ml. the ED75, ED50 and ED25 of standard curve were 1.30, 3.71 and 10.60 ng/ml, respectively. Both coefficients of variations between and within assay were less than 15%. Serial dilutions of chicken samples showed a parallel inhibition curve to that of the standards. Plasma PRL concentrations of samples from hens at different reproductive states measured by this assay revealed significant differences and rational changing trends. These results validate the assay