Histochemical observations on the oxidative enzyme activity and hemoglobin synthesis in the developing erythrocytic cells of the embryonic liver,

Abstract

A histochemical study of the variations in oxidative enzymes, protein‐bound amino acids (histidine, tyrosine, tryptophane, cysteine and cystine), ribonucleo‐protein and hemoglobin was made on the erythrocytic cells during the process of erythropoiesis in the embryonic liver of the rabbit.Increases in the cytoplasmic content of protein‐bound sulfhydryls and histidine were noted prior to the appearance of histochemically detectable hemoglobin and were nearly inversely related to the staining reaction for ribonucleoprotein. Changes in the oxidative enzyme activity of the developing erythrocytic elements appeared to reflect changes in the number of mitochondria present within these cells at various stages in the process of maturation. No visible changes were observed in the intensity or localization of the histochemical reactions for oxidative enzymes in the mitochondria of the erythrocytic elements except for an apparent slight increase in activity during mitosis. Two forms of hemoglobin were identified, one acid‐soluble localized to the orthochromatic normoblasts and erythrocytes of the primary erythrocytic linage and the other acid‐resistant present in the erythrocytes and late stages of the developing erythrocytic cells of the secondary erythroid series. Histochemical variations occurring during erythpoiesis were discussed in relation to biochemical data concerning hemoglobin synthesis.