Relation of Porphyrin Content to Red Cell Age: Analysis by Fractional Hemolysis 1

Abstract

Summary

Procedures are described for the calculation of approximate half-times of unlabeled porphyrins (or of any compound) in circulating erythrocytes. These are based on a comparison of their distribution in fractionally lysed erythrocytes and the distribution within the same hemolysate fractions of cells of different ages. Cell age was determined by cohort labelling of new-formed hemoglobin following injection of glycine ¹⁴C or ⁵⁹Fe. Analysis of the distribution of uro, copro, and protoporphyrin in such hemolysates from a porphyric cow indicated that half-times of her erythrocyte uro and coproporphyrin were about 2 and 7 days, respectively, while erythrocyte protoporphyrin accumulated for several days in circulating reticulocytes before decreasing in concentration. Data favoring a half-time of 2-3 weeks for the major portion of erythrocyte protoporphyrin are cited.