ERYTHROCYTIC AND GRANULOCYTIC DIFFERENTIATION OF TRANSPLANTED BONE-MARROW CELLS IN MICE TREATED WITH THYROID-HORMONES

  • 1 January 1981
    • journal article
    • research article
    • Vol. 27  (2) , 126-134
Abstract
Feeding of C57BL mice with dried thyroid gland (added to their food) for 10 days activated 59Fe incorporation into splenic heme and decreases peripheral granulocyte levels. The importance of the differentiation of hemopoietic stem cells under these conditions was investigated by using repopulation assays. Transplantation of bone marrow cells into recipients irradiated on day 10 of treatment with thyroid hormones, i.e., in the phase of activation of erythropoiesis, results in an increase in erythropoiesis and a decrease in granulopoiesis. Following irradiation and transplantation of animals during the phase of rebound, i.e., .apprx. 5-8 days after cessation of thyroid hormone treatment, erythropoiesis is depressed and granulopoiesis is activated, the values exceeding markedly the control levels. The practical importance of changes in the host inductive milieu favoring granulopoiesis is documented; normal marrow evidently has an increased capacity to prolong the survival of animals lethally irradiated in the phase of rebound after pretreatment with thyroid hormones.