The process of hemoglobin sythesis in erythroid cells have been traced mainly by observing cells under the light of 4,060 Å. To scrutinize the theory of hemoglobin synthesis in the nucleus of erythroblasts, several
cytochemical and morphological observations were also carried out. The conclusions derived from them are as follows: 1 The absorption at 4,060 Å of the cell, which indicates the location of heme, appeared in the nucleus as early as in the develpmental stage of basophilic erythroblasts. The absorption of hcme in cytoplasm likewise appeared in this stage showing nearly the same intensity of the absorption. The absorption picture of heme in the nucleus, which is coincidental
with that of interchromatin, increased along with the progess of maturation as well as in the cytoplasm. The absorption in the nucleus disappeared at the orthochromatic stage where the picture of interchromatin
disappeared, while the intensity of absorption in the cytoplasm continued to increase till the stage of reticulocyte. 2 The pseudoperoxidase reaction of hemoglobin, the appearance of acidophlic protein and masked lipids detectable in the location of hemoglobin
gave an exactly identical picture with that of the absorption of heme in the nucleus as well as in the cytoplasm. 3 Permeability test performed by supravital staining with Nile blue revealed that the nucleus of erythroblasts from the basophilic to the orthorchromatic
stages has increased its permeability being stained selectively as in the case of dead cells. 4 The mitochondria and the endoplasmic reticulum proved to be
retained well in the entire course of hemoglobin synthesis, even after the denucleation, the reticulocyte stage. From these observations the authors believe that the hemoglobin syntheis will take place in the cytoplasm throughout the life cycle of erythroid cells, pointing out that the absorption picturebf heme appearing in the nucleus will be in all likelihood due to the infusion of the hemoglobin from the cytoplasm.</p
