Comparison of erythropoietic response to androgen in young and old senescence accelerated mice

In this study, to clarify whether the functional capacity of hemopoietic pr ogenitor cells and the micro-environment of aged mice are identical with th ose of the young, we investigated the changes in the number of hemopoietic progenitor cells and the production of regulatory cytokines from splenic ce lls as well as changes in the serum levels of cytokine in senescence-accele rated mice (SAM) after administration of 19-nandrolone decanoate (19-ND), a synthetic androgenic anabolic steroid. 19-ND induced an increase in erythr oid colony-forming units (CFU-E), erythroid burst-forming units (BFU-E), an d granulocytic-macrophage committed progenitor cells (CFU-GM) in bone marro w and spleen; especially remarkable increases were observed in the splenic CFU-E in both young and old mice. Antigen expression analysis of hemopoieti c organs revealed that total TER-119 + cells per spleen of young and old mi ce with androgen treatment rose 2.6- and 3.2-fold over their respective con trol values. The responsiveness of hemopoietic progenitor cells to androgen did not change with age. Injection of 19-ND into young and old mice marked ly enhanced the erythropoietin levels but not IL3 and GM-CSF levels in the serum of both groups. Cytokine production assessed by pokeweed mitogen-stim ulated spleen condition medium showed an age-related decline. Androgen trea tment could not influence IL-3 and GM-CSF production of spleen. These findi ngs suggest that the spleen of both old and young mice served as the major site of regenerative repopulation of hemopoietic progenitors, especially th e late erythroid progenitors in 19-ND-treated mice. The proliferative reser ve of erythropoiesis with androgen treatment in aged mice was not reduced m ore than that in treated-young mice. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.