ORIGINAL ARTICLE |
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Year : 2018 | Volume
: 41
| Issue : 1 | Page : 26-29 |
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Optimization of reagent concentration for radioiodination of rat C-peptide II in development of radioimmunoassay procedure for rats
BR Manupriya1, Shalaka Paradkar2, Lathika1, Shrikant L Patil3, HM Somashekarappa1, Bhasker K Shenoy1
1 Department of Applied Zoology and Centre for Application of Radioisotopes and Radiation Technology, Mangalore University, Mangaluru, Karnatak, India 2 Radiopharmaceuticals Production Programme, Board of Radiation and Isotope Technology, Navi Mumbai, Maharashtra, India 3 Department of Physiology, K.S. Hegde Medical Academy, Mangaluru, Karnatak, India
Correspondence Address:
Dr. Bhasker K Shenoy Department of Applied Zoology, Mangalore University, Mangalagangothri, Konaje, Mangalore - 574 199, Karnataka India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/rpe.RPE_11_18
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Rat C-peptide is a polypeptide molecule made up of 31 amino acids and secreted from pancreas into circulation in two isoforms I and II. Quantification of rat C-peptide II in rat serum is important as it is directly related to the diagnosis of carbohydrate metabolism abnormalities, pancreatic performance analysis, monitoring of hypoglycemia, and diabetes-related illness in rat model. The aim of the present work is to develop a tracer by chloramine-T method for radioimmunoassay (RIA) procedure and to determine the optimum amount of chloramine-T required for the preparation of stable radioiodinated product with a specific activity of around 24.97 MBq/μg, corresponding to 1 125I atom per molecule of the peptide. Tyrosylated rat C-peptide II was selected for the radioiodination procedure as rat C-peptide II does not contain either tyrosine or histidine which is mandatory for the incorporation of 125I atom to the rat C-peptide II. Tyrosylated rat C-peptide II was subjected to radioiodination by chloramine-T method with different concentrations of chloramine-T and sodium metabisulfite (MBS) to obtain a stable radiolabeled compound. Optimized reaction conditions relating to the concentration of chloramine-T (10 μg) and MBS (20 μg) yielded a stable 125I-rat C-peptide II with specific activity of 21.01 MBq/μg corresponding to 0.84 125I atoms per molecule of the peptide. Preparation of high integrity tracer of rat C-peptide II was achieved by combining one molecule of oxidant (chloramine-T) and two molecule of reductant (MBS). |
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