Role of glucocorticoids in early T-cell differentiation.
The results of the T-cell differentiation in the progeny of adrenalectomized pregnant rats (Adx fetuses), an experimental model that ensures the absence of glucocorticoids (GCs) during the first stages of development, are summarized. In Adx thymuses there is an accelerated maturation of thymocytes that is reversed by in vivo GC replacement. In addition, Adx thymuses show decreased cell content, which correlates with both the increased numbers of apoptotic cells and an early migration of DP (CD4+CD8+) and SP (both CD4+CD8- and CD4-CD8+) thymocytes to the spleen. As shown by in vitro recolonization assays, accelerated T-cell differentiation is a consequence of changes in the biology of lymphoid precursors occurring in the fetal liver of Adx fetuses. They arrive at the thymic primordium earlier and mature faster than the fetal liver lymphoid progenitors from Sham control fetuses. After the establishment of a fetal hypothalamus-pituitary-gland-adrenal-gland (HPA) axis, there is a gradual normalization of the T-cell development Adx fetuses.
Sacedón
R
R
Department of Cell Biology, Faculty of Biology, Complutense University, 28040 Madrid, Spain.
Vicente
A
A
Varas
A
A
Jiménez
E
E
Muñoz
J J
JJ
Zapata
A G
AG
D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D005260:Female; D005938:Glucocorticoids / Q000502:physiology*; D006410:Hematopoiesis; D011247:Pregnancy; D051381:Rats; D017208:Rats, Wistar; D013601:T-Lymphocytes / Q000166:cytology / Q000502:physiology*
D005938:Glucocorticoids