Synergistic action of human fetal liver cells and growth hormone on stimulation and inhibition of myelopoiesis
Reinerová, M.; Reiner, P.
Neoplasma 38(2): 175-183
1991
ISSN/ISBN: 0028-2685 PMID: 2041577 Document Number: 381727
Human fetal hepatocytes from midtrimester fetuses were studied in their ability to support pluripotent hemopoietic progenitor cells (GEMM-CFU) and myeloid progenitor cells (GM-CFU). We compared the activity of fetal liver stroma to stimulate hemopoiesis of mixed and myeloid lineages without hormonal additional and by influence of human pituitary growth hormone (hGH). Colony-forming assays in a double-layer semisolid agar system were used. This study shows that addition of hGH to the fetal liver stroma has enhancing activity upon formation of myeloid colonies. It seems that this activity is not mediated through liver macrophages but by releasing other hepatocyte-derived factors, perhaps by somatomedins. A model of such regulation is proposed. Further, there were observed small, lymphocyte-like cells close to the germinal center of colonies. They are supposed to be the first maturated cells in myeloid colony cell population and to exert inhibitory role on pluripotent stem cell (PSC) self-renewal by direct cell-to-cell contact.