STUDIES OF PROTOPORPHYRIN: IV. A COMPARISON OF THE ERYTHROCYTE PROTOPORPHYRIN CONCENTRATION WITH THE RETICULOCYTE PERCENTAGE UNDER EXPERIMENTAL AND CLINICAL CONDITIONS 1

Abstract

In acute phenylhydrazine anemia in 5 rabbits and 1 dog, the reticulocyte percentages and erythrocyte protoporphyrin content were closely parallel. The method employed for detn. of protoporphyrin in the erythrocytes was that described in a preceding paper by Grinstein and Watson. The protoporphyrin was isolated as the crystalline dimethyl ester of melting point 219[degree] C (protoporphyrin 9 corresponding to aetioporphyrin III). In cases of pernicious anemia treated with concentrated liver extract, the increase in erythrocyte protoporphyrin lagged considerably behind the reticulocyte rise. The reason for this is not clear. Certain possible explanations are considered. Sterile incubation experiments revealed an increase in the erythrocyte protoporphyrin in spite of diminishing reticulocyte percentage. Although increased reticulocyte percentages are regularly associated with increased erythrocyte protoporphyrin, a strict correlation was not observed. In Fe deficiency anemia very marked elevations of porphyrin were noted with but slight or moderate increases in reticulocyte percentage. In two cases of myelopthisic anemia due to leukemia, no reticulocytes were found, yet the erythrocyte protoporphyrin was moderately increased. Three factors are believed important with respect to the presence and to increased amts. of the erythrocyte protoporphyrin normoblastic erythro-poietic activity; Fe deficiency, or disturbed synthesis of Hb due to poisons or toxins (heavy metals); and intracor-puscular degradation of small fractions of the Hb.