The red cells of rats and mice were tagged in vivo by injection of diisopropylphosphorofluoridate (DFP), labeled with P32, and the disappearance of radioactivity from the circulating red cells was determined. From the data obtained, it is concluded that the disappearance of the red cells is linear with time and that the red cells in both rats and mice have a true life span without measurable random destruction.
The life span of the erythrocytes was found to be 60.0 ± 3.2 (S.D.) days in the rat and 40.7 ± 1.9 (S.D.) days in the mouse.
Especially in the mouse the determination of the red cell life span with DFP32 is a simple procedure.