Factors affecting haemoglobin synthesis in the mouse

The effect of various forms of haematopoietic stress on haemoglobin production was studied in mice. During acute anaemia, recovery from polycythaemia or irradiation, there was an increase in the number of reticulocytes, and this was associated with a marked increase in the total protein synthesis. The specific activity in reticulocytes increased up to 20-fold from the normal. The maximum specific activity usually preceded the maximum peak of reticulocytosis. The proportion of minor haemoglobin increased by up to 30%, and there was a significant correlation between the specific activity in reticulocytes and the proportion of minor haemoglobin synthesized. These results indicate that erythropoietic stress results in the release of a new population of reticulocytes that are very active in protein synthesis as measured by markedly increased specific activity, and that this coincides with an increase in the proportion of minor haemoglobin produced.