EFFECTS OF 12-0-TETRADECANOYLPHORBOL-13-ACETATE (TPA) ON THE PROLIFERATION OF GRANULOCYTE-MACROPHAGE COLONY-FORMING CELLS

Abstract

It has been suggested that 12-0-tetradecanoylphorbol-13-acetate (TPA) may stimulate the proliferation of granulocyte-macrophage (GM) colony-forming cells (CFC) via the GM colony-stimulating factor (CSF) receptor. GM-CFC in unfractionated mouse bone marrow and light density fetal liver (LDFL) cells were induced by TPA to form colonies in the absence of exogenously added GM-CSF. The colonies induced by TPA (10(-8)M) were smaller than normally seen with maximal concentrations of GM-CSF, and less than 30% of the GM-CFC formed colonies in the presence of TPA. The number of colonies stimulated by TPA in the absence of GM-CSF was dependent on the number of cells plated. When fewer than 10,000 bone ..