Erythrocytes of different ages: a new method of 'in vivo' preparation

This paper describes a new method for obtaining "in vivo" populations of homogeneous erythrocytes of a specific age. This method, proposed for experimental animals, is based on the induction of a large reticulocytosis (about 80%) by the administration of phenylhydrazine and the subsequent synchronized ageing of young red cells present, which is obtained by blocking the erythropoiesis with daily injections of Actinomycin D. The advantage of such a method over those published so far is that it produces substantial quantities of red blood cells of a specific age. A disadvantage however is that it is only possible to obtain cells of up to 30 days old.