STUDIES ON HYPOXIA. II. A QUANTITATIVE STUDY OF CHANGES IN THE BONE MARROW OF THE GUINEA PIG DURING POST-HYPOXIC POLYCYTHEMIA (REBOUND)

Abstract

Quantitative studies were made of the changes in the blood and bone marrow during post-hypoxic polycythemia in 25 guinea pigs. The polycythemic animals showed clear evidence of depressed erythropoiesis. The blood reticulocytes fell sharply on the second day, and were less than 1/3 their normal level by the fifth day though they never completely disappeared. The marrow reticulocytes which fell significantly though not so sharply as those of the blood never completely disappeared. The nucleated erythroid cells of the marrow which increased slightly on the first day fell sharply to well below their control level by the 5th day. Changes in erythropoiesis are initiated from the stem cell end. Though erythropoiesis was markedly depressed, it never ceased completely.