title: Influence of the tumour promoter TPA upon erythroid burst formation in vitro.
abstract: A dose dependent effect of the tumour promoter TPA on burst formation by rabbit erythroid progenitors (BFU-e) was demonstrated in cultures deficient in the early erythroid regulator burst-promoting activity (BPA). In these culture conditions the burst number was highest (193% of controls) at 10(-9)M TPA and concentrations higher than 3 x 10(-9)M TPA were inhibitory. The degree of burst enhancement by TPA and bone marrow conditioned medium as a source of BPA was similar. The addition of optimal concentrations of both TPA and BPA simultaneously to cultures resulted in no further increase in burst number. Short-term incubation of bone marrow cells with TPA failed to enhance the percentage of S-phase BFU-e under conditions in which BPA significantly increases the number of BFU-e in the cell cycle. These results indicate that the same population of BFU-e responds to TPA and BPA, but TPA does not mimic the mitogenic effect of BPA upon BFU-e.
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004912:Erythrocytes / Q000187:drug effects / Q000502:physiology*; D006412:Hematopoietic Stem Cells / Q000187:drug effects / Q000502:physiology*; D007399:Interphase / Q000187:drug effects; D010704:Phorbols / Q000494:pharmacology*; D011817:Rabbits; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
chemical_list: D010704:Phorbols; D013755:Tetradecanoylphorbol Acetate