Preparation of 125I-labeled synthetic porcine secretin for radioimmunoassay.
Synthetic porcine secretion was labelled by the conjugation-labelling method of Bolton & Hunter, the lactoperoxidase method, the gaseous diffusion method, and the chloramine-T method. The chloramine-T technique was adapted as routine method. Ten mug (3.27 nmol) peptide was reacted with 5 mCi of Na125I at a concentration of chloramine-T of 1.3 mmol/l. Synthetic secretin was suitable for labelling for at least eight months when stored as dry matter in nitrogen-filled glass ampoules. Purification and separation of labelled from unlabelled hormone was carried out by gel-permeation chromatography on Sephadex G-50 superfine. The labelled preparation had a specific radioactivity of 405 +/- 33 muCi/nmol (mean +/- SEM., n = 9) and was unable for six days. 6-tyrosyl-secretin took more iodine compared to porcine synthetic secretin but had lower immunoreactivity with all antisera tested.
D000818:Animals; D005069:Evaluation Studies as Topic; D006863:Hydrogen-Ion Concentration; D007457:Iodine Radioisotopes; D007467:Iodoproteins / Q000032:analysis; D007553:Isotope Labeling / Q000379:methods; D008297:Male; D011863:Radioimmunoassay / Q000379:methods; D012633:Secretin / Q000032:analysis; D013552:Swine
D007457:Iodine Radioisotopes; D007467:Iodoproteins; D012633:Secretin