title: Normal embryo fibroblasts release transforming growth factors in a latent form.
abstract: Normal chicken, mouse, and human embryo fibroblasts release into their culture media transforming growth factors (TGFs) in a latent form. Their soft agar colony-forming activity on two widely used target cells, rat NRK-49F and mouse AKR-2B, is essentially revealed only after prior acidification of cell-conditioned media. These TGFs are EGF-dependent when assayed on NRK-49F cells and EGF-independent on AKR-2B cells. The TGF activity from the chicken source is released in three (apparent) molecular weight forms of 500 kd, 125 kd, and 20 kd.
mesh_terms: D000818:Animals; D002453:Cell Cycle; D002642:Chick Embryo; D004622:Embryo, Mammalian / Q000502:physiology; D066246:ErbB Receptors; D005347:Fibroblasts / Q000502:physiology*; D006133:Growth Substances / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D051379:Mice; D008970:Molecular Weight; D010455:Peptides / Q000378:metabolism*; D051381:Rats; D011956:Receptors, Cell Surface / Q000378:metabolism; D015291:Transforming Growth Factors
chemical_list: D006133:Growth Substances; D010455:Peptides; D011956:Receptors, Cell Surface; D015291:Transforming Growth Factors; D066246:ErbB Receptors