Mechanism of Action of Radiation Protective Agents: In vivo Distribution and Metabolism of Cysteamine-S-Phosphate (MEAP).
Annual rept. 1 Jul 68-30 Jun 69,
ALBERT EINSTEIN MEDICAL CENTER PHILADELPHIA PA RADIATION RESEARCH LAB
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The appearance of a new class of protective agents, the aminoalkyl-thio-phosphates or aminoalkyl-phosphorothioates, provided the opportunity to re-evaluate these proposed mechanisms of action. The new compounds are less toxic than the aminoalkylthiols and provide equal or better protection. A study of the distribution and metabolism of one of these agents, aminoethylthiophosphate or cysteamine-S-phosphate MEAP was undertaken to test the hypotheses arrived at in the mechanism studies of mercaptoethylguanidine and bis2-guanidoethyl disulfide. In this study, the protective agent MEAP labelled with P-32 and S-35 was analyzed in pure solutions, in homogenates of mouse tissues in vitro and in homogenates of tissues from mice given protective doses of MEAP in vivo. A small radiation mortality study was run concurrently with the distribution and metabolism studies in order to be sure that the analyzed mice were really being studied under conditions of protection. Keywords Radiation dosage, Protective agents, Organic compounds, Toxicity, UA Reports. JG