Actinomycin D and radiation: effects on mouse lung.

The effect of actinomycin D (0.4 mg/kg) on radiation-induced lung damage in the mouse was investigated. The drug was administered either 4 weeks before, immediately after, or 16 weeks after single doses of 240 kV X-rays applied to the thorax of CBA mice. Lung damage was assessed by measuring respiration rate, with a whole body plethysmograph. Dose-response curves were obtained at 2-week intervals from 12 to 40 weeks after irradiation. Actinomycin D had no significant effect on respiration rate in this study. A summary of other experimental studies is included which shows conflicting results.