Preparation of high-specific-activity radioactive iodothyronines and their analogues. [/sup 125/I, /sup 131/I]

Journal Article · Tue Nov 01 04:00:00 EST 1977 · J. Nucl. Med.; (United States)

OSTI ID:5360397

Nakamura, Y; Chopra, I J; Solomon, D H

In order to obtain radioactive iodothyronines of high specific activity, suitable for use in radioimmunoassays, we have used chloramine-T as the oxidizing agent to attach radioiodine to various iodothyronines including 3-iodo-L-thyronine (3-T/sub 1/), 3'-iodo-L-thyronine (3'-T/sub 1/), 3-5-diiodo-L-thyronine (3,5-T/sub 2/), 3,3'-diiodo-L-thyronine (3,3'-T/sub 2/), 3,5,3'-triiodo-L-thyronine (T/sub 3/) and some of their analogues, e.g., 3,5-diiodothyropropionic acid (3,5-Diprop), and 3,5,3'-triiodothyropropionic acid (Triprop). Radioiodine incorporated into iodothyronines was separated from unreacted radioiodide by column chromatography using LH-20 Sephadex, and the various radioactive iodothyronines produced during iodination were separated by descending paper chromatography using hexane, tertiary amyl alcohol, and ammonia. In the case of each substrate, radioactive products produced were those that would result from the radiolabeling of the 3' and/or 5' position of the iodothyronine molecule; compounds that would be produced from radiolabeling of the inner ring of the iodothyronine molecule were never detected. While exchange labeling of outer-ring iodine atoms did occur, addition of an iodine atom to the outer ring was far more common. Our data suggest that the chloramine-T method is practical and convenient to render any iodothyronine (or its analogue) radioactive in the outer ring; and specific activity of the radioactive product and yield of iodination are particularly high when the substrate for iodination has one less iodine atom in the outer ring than the one desired.

• Research Organization: Univ. of California, Los Angeles
• OSTI ID: 5360397
• Journal Information: J. Nucl. Med.; (United States), Journal Name: J. Nucl. Med.; (United States) Vol. 18:11; ISSN JNMEA
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400702* -- Radiochemistry & Nuclear Chemistry-- Properties of Radioactive Materials
AMINES
AMINO ACIDS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBOXYLIC ACIDS
CHEMICAL PREPARATION
CHEMICAL REACTIONS
CHLORAMINES
CHROMATOGRAPHY
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
HALOGEN COMPOUNDS
HORMONES
HYDROXY ACIDS
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE 131
IODINE COMPOUNDS
IODINE ISOTOPES
ISOTOPES
LABELLING
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
PEPTIDE HORMONES
RADIOISOTOPES
SEPARATION PROCESSES
SYNTHESIS
THYRONINE