Partial purification and characterisation of a renal growth factor from plasma of uninephrectomised rats

Renal growth factor activity was extracted from plasma of adult uninephrectomised rats and partially purified by gel filtration and anion-exchanger FPLC. It induced a maximal stimulation of mouse DNA synthesis in vivo at 1.75 micrograms/mouse. In addition, renal growth factor was found to maximally stimulate DNA synthesis in LLC-PK1 cells at 150 ng/ml. This maximal response was then found to decrease with higher doses of renal growth factor, in vivo and in vitro. The apparent molecular weight of renal growth factor was estimated to be 17K-22 K by gel filtration. It was found to be resistant to heat and to trypsin, but labile to reduction with dithiothreitol.