Blood, 1964, Vol. 24, No. 5, pp. 582-593.
© 1964 American Society of Hematology, Inc.
Macrocytosis Resulting from Early Denucleation of Erythroid Precursors
SATIMARU SENO 1,
MASANOBU MIYAHARA 1,
HIKARU ASAKURA 1,
OSAMU OCHI 1,
KENICHI MATSUOKA 1, and
TAKENORI TOYAMA 1
1 Department of Pathology, Okayama University Medical School, Okayama,
Japan.
In an attempt to elucidate the mechanism of production of macrocytosis in
acute anemia, we studied changes in red cell volume and hemoglobin content, the RNA level of normoblasts and reticulocytes and RNA synthesis in
reticulocytes of rabbits made anemic by blood loss or phenylhydrazine administration. The results were as follows:
(1) In severe phenylhydrazine anemia, red cell volume and hemoglobin
content per cell increased to twice the normal values.
(2) The RNA level of normoblasts decreases with the maturation of the
cells and reaches a minimum at the orthochromatic stage. The decrease is
similar in the normal and anemic rabbits.
(3) The RNA level of reticulocytes in the bone marrow is higher in anemic
than in normal rabbits. In general, the RNA level of reticulocytes of anemic
rabbits is comparable to that of the polychromatic normoblasts, while in normal rabbits this value is comparable to that of orthochromatic normoblasts.
(4) Autoradiographs of reticulocytes incubated with H3-uridine indicate
that the increased level of reticulocyte RNA of anemic rabbits is not due to
newly synthesized RNA.
From these results, we conclude that in an "emergency" situation of erythropoietic stimulation denucleation of normoblasts occurs at the polychromatic
stage of red cell maturation, with skipping of the terminal cell division to
orthochromatic cells and formation of macrocytic reticulocytes and red cells.
Submitted on August 28, 1963
Accepted on April 30, 1964
