Summary
Plasma collected from the spleen of rabbits 2 to 4 hr after selective splenic irradiation decreased from 75 to 95% the uptake of 125I-labeled 5-iodo-2′-deoxyuridine by a suspension of bone marrow cells from untreated rabbits. The factor responsible for the decreased uptake was found to be dialyzable and, on paper chromatography in 4 different solvent systems, had the same RF values as did thymidine. Serial dilutions of this factor gave a dose-related response in the bone marrow suspensions that was identical to that obtained with thymidine, 0.01 to 0.25 µg/ml, confirming the chromatographic identification of the plasma factor as thymidine. The extent of thymidine release as measured by this sensitive method may be useful in evaluating early cell damage following X-irradiation.
Footnotes
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↵1 Supported by Research Grants CA-5834 and CA-12585 from the NIH, USPHS, and by Grants 3.114.69 and 3.386.70 from the Fonds National Suisse de la Recherche Scientifique.
- Received June 12, 1972.
- Accepted September 13, 1972.
- ©1972 American Association for Cancer Research.