Radioprotective Action of SH Compounds Ⅰ. Stusies Based on Survival Rate Curve

The radioprotective effect of SH compounds (GSH, MEA, AET, MPG and DTT) was studied by using of 30-day survival rate in mice and obtained the following results. 1. DRF (dose reduction factor) of GSH (30 mg), MEA (4 mg), AET (3 mg) and AET 86 mg) was 1.09, 1.54, 1.29 and 1.31 at LD50 respectively. 2. The dose-effect curve og GSH and MEA had a slope approximately similar to that of the contral group. The slope was less steep for AET. 3. n administering MEA at intervals of 60 minutes before irradiation and 30 minutes after irradiation, the best effect was obtained with administration 30 minutes before irradiation. 4. When the GSH administration was shifted to repeated irradiation, positive effect was obtained in the administration at 3 hours or 30 minutes before irradiation and a poorer effect in the administration at 6 hours before irradiation. Administration after irradiation gave no effect. 5. When the GSH administration was shifted to repeated irradiation, 30 mg of GSH gave the best effect. 6. Protective effect other compounds in the dose of 3 mg, 6 mg AET or 3 mg MEA, was also observed for repeated irradiation. AET (6 mg) had the best protective effect of all the SH compounds tested. On the basis of these experimental results, the author explained the radioprotection of SH compounds.