Abstract
Through an in vivo and in vitro analysis of the absorption kinetics of S-2-(3-aminopropylamino)ethylphosphorothioic acid (WR-2721) in the normal tissues and solid tumors of mice, rats, and rabbits, it has been demonstrated that normal tissues actively concentrate WR-2721 against a concentration gradient, whereas solid tumors passively absorb it, or, if active concentration of WR-2721 is present in tumors, it operates at a far reduced rate relative to normal tissues. These observations can account for the ability of WR-2721 to selectively protect normal tissues against both radiation and alkylating agent injury.
Footnotes
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↵1 Supported by Grants CA-21074-03 and CA-19326-02 A1 from the National Cancer Institute, Department of Health, Education, and Welfare.
- Received June 25, 1979.
- Accepted February 1, 1980.
- ©1980 American Association for Cancer Research.
