Effect of estradiol on splenic repopulation by endogenous and exogenous hemopoietic cells in irradiated mice
✍ Scribed by V. K. Jenkins; A. C. Upton; T. T. Odell Jr.
- Publisher
- John Wiley and Sons
- Year
- 1969
- Tongue
- English
- Weight
- 661 KB
- Volume
- 73
- Category
- Article
- ISSN
- 0021-9541
No coin nor oath required. For personal study only.
✦ Synopsis
Estradiol treatment of irradiated mice during repopulation of their spleens by endogenous hemopoietic cells reduced the number of myelocytic colonies and increased the numbers of erythropoietic and undifferentiated colonies. The in- hibitory effects of the hormone on myelopoiesis were not dependent on stimulation of erythropoiesis, since they occurred in the absence of erythropoiesis in mice made polycythemic by hypertransfusion.
Treatment of bone marrow donors with estradiol reduced the abdity of their marrow cells to form spleen colonies, particularly reducing the proportion of myelopoietic colonies relative to the total number of colonies of all types. Conversely erythropoietic colonies, though reduced in absolute number, were increased in relative number. Such treatment also decreased the volume and cell content of the marrow cavity through stimulation of endosteal bone formation.
Estradiol treatment of lethally irradiated recipient mice did not detectably alter the total numbers or types of hemopoietic spleen colonies formed in these animals from transplanted marrow cells; however, without estradiol treatment, myelopoietic colonies were so few and erythropoietic colonies so numerous that the effects of the hormones may have been undetectable by the methods employed.
The sex of the donor or recipient mouse did not affect the numbers or types of colonies formed, suggesting that endogenous levels of estradiol were too low to exert effects dectectable by the methods used. However, since our mice were only 8 weeks old, the data do not exclude the possibility that older female mice, with higher levels of estradiol, would have differed from males in relative numbers of myelopoietic as compared with erythropoietic colonies. '64a; Fruhman, '66; Hodgson, '62; Hughes et al., '64; Smith, '64).
Various diseases of the hemopoietic system, such as leukemia, reflect disturbances of the control of hemopoietic cell growth and differentiation. Since sex hormones have been found to influence the pathogenesis of spontaneous (Kaplan and Brown, '51), radiation-induced (Upton et al., '58), and viral (Jenkins, Odell and Upton, '66; Jenkins and Upton, '63) leukemias in animals, this experiment was undertaken to assess the effect of estradiol on hemopoietic cell growth and differentiation. Another objective was to explore the hypothesis that inhibition of myelopoiesis may account in part for the inhibitory effects of