Expression of 20-alpha-hydroxysteroid dehydrogenase in mouse macrophages, hemopoietic cells, and cell lines and its induction by colony-stimulating factors.

The enzyme 20-alpha-hydroxysteroid dehydrogenase (20 alpha SDH) has been proposed as a T lymphocyte marker that is specifically induced by interleukin 3. We have examined the expression of 20 alpha SDH and its relationship to interleukin 3 responsiveness in other hemopoietic lineages. The enzyme is expressed at high levels in the bone marrow of athymic nu/nu mice, but only at low levels in nu/nu spleen and normal adult bone marrow. 20 alpha SDH is induced in nu/nu spleen and in normal fetal liver cells by granulocyte-macrophage colony-stimulating factor (GM-CSF) as well as by interleukin 3. In longer term cultures of fetal liver and adult marrow, macrophage colony-stimulating factor (M-CSF) also induces the enzyme, which is expressed in proliferating adherent macrophages. The high levels of 20 alpha SDH in purified bone marrow-derived macrophages are maintained by M-CSF, GM-CSF, or interleukin 3. Expression of 20 alpha SDH in these cells is associated with resistance to growth inhibition by progesterone. Additional evidence against the restriction of 20 alpha SDH to T lymphocytes is found in its presence in peritoneal macrophages, myelomonocytic and macrophage-like cell lines, and the L929 fibrosarcoma line. We conclude that 20 alpha SDH is a normal enzyme of proliferating hemopoietic cells irrespective of their lineage or growth factor responsiveness.