The Formation of Monoiodotyrosine From Radioiodine in the Thyroid of Rat and Man
- 1 October 1948
- journal article
- research article
- Published by American Association for the Advancement of Science (AAAS) in Science
- Vol. 108 (2805) , 358-359
- https://doi.org/10.1126/science.108.2805.358
Abstract
Ten rats were given an intraven. or intraperit. injn. of 0.05-1 me. of carrier-free I131 and sacrificed 1 min. to 10 days later. The thyroids received 0.5 to 40,000 rep. (roentgen equivalents, physical) of beta radiation, delivefed at rates from 30 to 10,000 rep./hr. Parts of the thyroid were hydrolyzed in sealed tubes at 100 C with 8% Ba(OH)2.8H20 for 6 hrs., 2 [image] NaOH for 10 hrs., or 6 [image] HClfor 24 hrs. The HC1 hydrolysate was evaporated as a spot directly on filter paper. The NaOH hydrolysate was adjusted to pH 4, and a butyl alcohol extract was applied to the paper. The Ba(OH)2 hydrolysate was adjusted to pH 8, centrifuged, and the supernatant used to prepare the chromatogram. Two-dimensional chromato-grams were developed at 26 C with phenol as the 1st solvent and the upper phase from a sec-butyl alcohol, tert.-alcohol and water mixt. as the 2d solvent. Radio-autographs were made, the corresponding parts of the filter paper cut out for Geiger counter measurements, and the chromatograms sprayed with ninhydrin. In 40 chromatograms a radioactive spot appeared with RF values between those of tyrosine and diiodotyrosine. When monoiodotyrosine was added, it gave a ninhydrin spot corresponding in place and shape with the radioactive spot. A chromatogram was made from a Ba(OH)2 hydrolysate of a thyroid biopsy specimen from a patient with an adenoma of the thyroid 8 days after oral admn. of I131, it showed a radioactive spot corresponding to monoiodotyrosine and containing half the amt. of radioactivity of the diiodotyrosine spot. The possibility was checked that radioactive monoiodotyrosine might have been formed by exchange with or decomposition of, other iodine-containing substances of the thyroid during the processing of the tissue. The compound was present before processing.Keywords
This publication has 3 references indexed in Scilit:
- Application of Filter Paper Partition Chromatography to Radioactive Tracer StudiesNature, 1947
- The Quantitative Chromatography of Silk HydrolysateScience, 1947
- Mono-iodotyrosineBiochemical Journal, 1944