Transforming growth factor (TGF) activity in human urine: synergism between TGF-beta and urogastrone.

Human urine contains an acid and heat stable peptide with an apparent molecular weight of 8,000-10,000 that, in the presence of urogastrone (EGF), induces the anchorage-independent growth of nontransformed cells in semisolid media. This nonmitogenic growth-modulating activity does not compete with EGF for binding to EGF membrane receptor sites and can be resolved from EGF by high-performance liquid chromatography. The urine-derived growth factor has been purified more than 10,000-fold and shares many biochemical properties with and is functionally related to the B class of TGFs isolated from transformed cells and non-neoplastic tissues. The low molecular weight anchorage-independent growth-stimulating activity universally present in human urine is a result of the synergistic interaction of this urine-derived TGF-beta and urogastrone.