INCREASED RADIORESISTANCE IN MICE INJECTED WITH URETHANE TWO DAYS BEFORE X-IRRADIATION
Abstract
The possibility of altering radiosensitivity of mice by repeated injections of urethane was investigated. Adult female mice received two intraperitoneal injections of an aqueous solution of urethane (1 mg/g body wt), one day apart. Twenty-four hours after the last injection, the mice were exposed to a single acute dose of 250 kvp X-rays, in the midlethal or lethal range. The 30-day LD(50) for the urethane-treated mice was found to be 970 r; the LD(100) was 1010 r. The corresponding values for the control irradiated mice were 790 r and 840 r, respectively. The radioprotective effect of urethane was not seen when the drug was administered 30 min before irradiation, nor when the mice were irradiated 7 days after the last urethane injection. The protective effect could not be duplicated by preradiation exposure (1 or 2 days prior) to 100 r, 200 r, or 300 r. Non-irradiated mice given two daily injections of urethane as above exhibited a marked fall within 24 hours, in the total nucleated cell count of femoral marrow and peripheral blood, accompanied by a definite increase in the myeloid/lymphoid cell ratio of the blood. The results suggest that urethane-induced alterations in cell population of bone marrow are accompanied by an increase in the number of relatively radioresistant cell types, involved in myelopoiesis. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 10, 1961
- Accession Number
- AD0262307
Entities
People
- L.j. Cole
- S.r. Gospe
Organizations
- Naval Radiological Defense Laboratory