It has been reported that the appearance of small megakaryocytes can be detected in various blood diseases and in fetal hematopoiesis.
In the studies reported herein, we have investigated the age changes in the area of megakaryocytes during fetal stage to the newborn infant, infant, and adult stage.
The megakaryocyte increased in size from ago of 5 months to 10 months in fetal stage, and then at the age of one year after birth reached a size almost identical to that of adults.
In comparing the megakaryocyte area by fetal age, however, the significant difference was not observed in the hepatic and the bone marrow hematopoiesis at the age of 5 and 7 months.
The results in comparing the area ratio of the nucleus to the cytoplasm of megakaryocytes indicated that the nucleus of fetel megakaryocytes is generally smaller than that of adult marrow megakaryocytes.
This finding suggests that the size of the nucleus of megakaryocytes enlarges with increase in the area of megakaryocytes.
It is also considered that the functional or morphological changes of megakaryocytes may reflect the function or morphology of the platelet.