EXPRESSION OF 20-ALPHA-HYDROXYSTEROID DEHYDROGENASE IN THE MOUSE MARROW-CELLS - STRAIN DIFFERENCES, THYMIC EFFECT ON ENZYMATIC-ACTIVITY, AND POSSIBLE LOCALIZATION IN PRE LYMPHOCYTES-T

  • 1 January 1981
    • journal article
    • research article
    • Vol. 2  (6) , 305-320
Abstract
The enzyme 20.alpha.-hydroxysteroid dehydrogenase (20.alpha.SDH) was studied in bone marrow cells from various strains. The bone marrow cells of congenitally athymic (nude) and normal BALB/c mice consisted of 2 subpopulations of nucleated cells, larger cells of 10-14 .mu.m and smaller cells of 7 .mu.m in size. About 75% of the 20.alpha.SDH activity was located in the larger cells. Bone marrow cells from young neonatally thymectomized or congenitally athymic mice had an increased big cell portion and contained twice as much 20.alpha.SDH activity as control mice. Liver cells from 1-day-old mice and spleen cells from mice lethally irradiated and bone marrow reconstituted, both of which contained primarily stem cells, erythroid, myeloid and pre-B lymphocytes, had essentially no 20.alpha.SDH. Following stimulation with PHA [phytohemagglutinin], marrow cells from athymic nude mice responded to the mitogen in terms of [3H]thymidine incorporation and stimulation of 20.alpha.SDH activity. Bone marrow cells after stimulation with PHA were labeled with fluorescein-conjugated anti-.theta. antibodies. A fluorescence-activated cell sorter showed that the fluorescent cells had 2.5- to 5-fold more 20.alpha.SDH activity than the unlabeled cells. Apparently the 20.alpha.SDH activity is located in the marrow pre-T lymphocytes.