Distribution of Go 60 B 12 in Blood of Chickens and Rabbits. ∗

Summary

The distribution of radioactivity between plasma and erythrocytes was determined in 30-day-old rabbits and newly-hatched chicks fed Co⁶⁰ cyanocobalamin supplemented diets for 8 and 11 weeks respectively. In chick blood, 87% of the radioactivity was found in plasma, and all of the radioactivity was present in plasma of the rabbits. The distribution was not altered when the animals were depleted of vit. B₁₂ for 2 weeks. The small amount of radioactivity present in erythrocytes was firmly bound and less than 20% was removed by washing the cells 4 times with saline.