Proliferation of megaloblasts in pernicious anemia as observed from nucleic acid metabolism.

M EGALOBLASTIC ANEMIA is due chiefly to deficiency of vitamin B12 ( B12 ), of folic acid, or of both. Recent studies3’4’12’22 have been focused on the view that the metabolic defect leading to megaloblastosis may, in some way, be related to nucleic acid metabolism. However, the role of B12 coenzymes in mammalian nucleic acid metabolism has not been elucidated, nor are there exact data on the nature of the defect in the proliferative capacity or mitotic cycle of megaloblasts.”4’15’17’18’20’22’24-26 The present study was undertaken ( 1 ) to clarify the cytokinetic patterns of DNA, RNA, and protein synthesis in the megaloblasts in cases of B12 deficiency, using microphotometric DNA measurement and in vitro autoradiography (2), to obtain further information on DNA synthesis in individual megaloblasts by means of the combined method of microphotometry and autoradiography (3), to elucidate the effect of specific B12 therapy on these patterns of synthesis, and (4) to relate the findings to current concepts of megaloblastic hemopoiesis.