title: A systematic approach to the preparation of 125I-labeled gastrointestinal regulatory peptides with high specific radioactivities.
abstract: A systematic approach is outlined for the preparation of a whole series of immunoreactive 125I-labeled gastrointestinal regulatory peptides with high specific radioactivities. In our hands, the theoretically superior Iodo-gen method has no more to offer than the harsher chloramine-T method in the iodination of secretin, vasoactive intestinal polypeptide, gastric inhibitory polypeptide, and motilin; whereas the gentler Iodo-gen method has to be used to obtain fully immunoreactive cholecystokinin39 (CCK39) and Tyr1-somatostatin tracers. By applying the iodination mixtures on a Sephadex G-15 or a Sephadex G-10 column followed by an SP Sephadex C-25 column--being eluted under so-called 'finite adsorption equilibrium' between the peptides to be purified and the adsorbent--highly purified tracers are obtained with unusually high specific radioactivities. Stored at -20 degrees C in diluted aliquots of from 200 to 500 microliter, these tracers can be used for radioimmunoassay purposes without rechromatography for at least 60 days.
authors.forename: P G
authors.initials: PG
authors.lastname: Burhol
authors.forename: R
authors.initials: R
authors.lastname: Jorde
authors.forename: J
authors.initials: J
authors.lastname: Florholmen
authors.forename: T G
authors.initials: TG
authors.lastname: Jenssen
authors.forename: B
authors.initials: B
authors.lastname: Vonen
mesh_terms: D002766:Cholecystokinin / Q000032:analysis / Q000031:analogs & derivatives; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D005749:Gastric Inhibitory Polypeptide / Q000032:analysis; D005768:Gastrointestinal Hormones / Q000032:analysis*; D006801:Humans; D007457:Iodine Radioisotopes; D007553:Isotope Labeling / Q000379:methods*; D009037:Motilin / Q000032:analysis; D010446:Peptide Fragments / Q000032:analysis; D011863:Radioimmunoassay; D012633:Secretin / Q000032:analysis; D013004:Somatostatin / Q000031:analogs & derivatives / Q000032:analysis; D014660:Vasoactive Intestinal Peptide / Q000032:analysis
chemical_list: D005768:Gastrointestinal Hormones; D007457:Iodine Radioisotopes; D010446:Peptide Fragments; D012633:Secretin; D014660:Vasoactive Intestinal Peptide; D013004:Somatostatin; D009037:Motilin; D005749:Gastric Inhibitory Polypeptide; C012088:somatostatin, N-Tyr(1)-; C032740:cholecystokinin 39; D002766:Cholecystokinin