[Role of prostaglandin E in modulation of granulopoiesis by marrow stroma]

The stroma layer (SL) cultured from mouse bone marrow cells for one week, had an inhibitory effect on the granulocyte-macrophage progenitor cells (CFU-GM). The inhibitory effect decreased in the 2nd week SL, while the 3rd week SL promoted CFU-GM growth greatly. When indomethacin (1 x 10(-7) mol/L) was added into the CFU-GM culture system, the score of CFU-GM on the 1st week SL was raised, and on the 2nd week SL was further increased significantly, but it leveled off on the 3rd week SL. The addition of exogenous 10(-8) mol/L PGF1 suppressed the CFU-GM growth on all the 1st to 3rd week SLs. When 1 x 10(-8) mol/L PGE1 was added with 2 x 10(-7) mol/L indomethacin, 1st week SL-CFU-GM increased to 42.61%, 2nd week SL-CFU-GM nearly to 100% of the control. For the 3rd week SL-CFG-GM, 1 x 10(-7) mol/L indomethacin was enough to reverse the inhibition induced by exogenous 1 x 10(-8) mol/L PGE1. It is suggested that definite amount of PGE was produced from cells in the 1st week SL. The secretion of PGE from SL was reduced during 2nd week, and almost stopped in the 3rd week SL. The results indicate that the modulation of granulopoiesis by marrow stroma is, at least partly, mediated by PGE.