Pharmacological studies on chemical protectors against radiation. V. Establishment of bioassay for radio-protector

Abstract

Examinations were made on the potency test method for chemical radio-protectors using the life-prolongation effect on X-irradiated mice as the indicator. Standards used for this test were AET and MEA. Male ddY mice were irradiated with 600-900 R of X-rays and the animals were observed for the next 90 days to find optimal conditions for the potency tests.1) When the survival rate of irradiated mice is to be used as the indicator for potency tests of radio-protectors, the mice should be irradiated with a dose of X-rays (700-900 R) by which all the control mice will be dead about 2 weeks after the irradiation and the survival rate of the mice in experimental group should be measured at the time when the survival rate of the control mice becomes 0%. 2) When the survival time of irradiated mice is to be used as the indicator for potency tests of radio-protectors, the mice should be irradiated with a dose of X-rays (700-800 R) by which the mean survival time of the control mice becomes about 10 days, mean survival time of the experimental group is measured 30 days after the irradiation, and protective potency is calculated by comparison of the mean survival time with that of the control group. 3) Comparison of the minimum effective does of AET and MEA indicated that there is a difference in the molar potency of the two compounds and AET was found to be 2-8 times stronger than MEA.