Magnesium perchlorate and cis-platinum as radiosensitizers in in vitro radiolysis of nucleotides.

The mechanism of the gamma-radiolysis of the nucleotide guanosine-5'-monophosphate (5'-GMP) in the presence of Mg++ ions and cis-platinum was investigated. From high performance liquid chromatography and spectroscopy studies it was found that the OH radicals, produced in irradiated aqueous solutions, reacted with 5'-GMP by addition to the double bonds and that Mg++ as well as cis-Pt sensitized the nucleotide to radiation damage. Furthermore, an important finding was the fact that when the irradiation took place in aerated solutions, the Mg++ ions, contrary to cis-Pt, did not seem to have any effect on the decomposition yield G(-5'-GMP). This result together with the sensitization (100% increase) observed in deaerated solutions led to the conclusion that irradiation in the presence of Mg++ may result in a more effective gamma-radiation therapy for tumours.