Effect of temperature on erythropoiesis and red cell survival in the frog

The effect of environmental temperature on erythropoiesis and erythrocyte life span was studied in frogs maintained at 4 C or 24–26 C. The red cell incorporation of radioiron was used as an index of the rate of erythropoiesis and diisopropylfluorophosphate-P32 was used to measure red cell survival. The red cell life span in frogs kept at 24–26 C was approximately 200 days. The incorporation of Fe59 into circulating red cells during the first 10 days after isotope administration was significantly greater in frogs at 24–26 C than in frogs at 4 C. The peripheral hematocrit decreased in groups of frogs kept at 4 C during the period of observation. The inconstancy of the hematocrit and presumably of the total red cell volume did not permit any definite conclusions regarding the apparently longer erythrocyte life span at low environmental temperatures.