Biological properties of a renotropic protein present in plasma of uninephrectomized rats

The biological characteristics of a kidney growth factor (KGF) from uninephrectomized rat plasma have been studied. A crude preparation of this factor [Nephrol. Dial. Transplant. 4: 334-338, 1989] was further purified by hydrophobic interaction HPLC and gel filtration. KGF was found to be a heat- and trypsin-resistant protein. This factor stimulated dose-dependently DNA synthesis by the mouse kidney in vivo, and by either rat renal tubules or serum-deprived LLC-PK1 cells, in vitro. KGF also increased protein synthesis in these cells, in a dose-dependent manner. Moreover, KGF stimulated sodium uptake by these cells, associated with the maximal increase of protein synthesis. Our findings indicate that KGF is a potent renotropic protein which can play a key role in the renal compensatory growth after uninephrectomy.