RABBIT AND HUMAN RENOTROPIN ARE NOT EPIDERMAL GROWTH-FACTOR

Sera obtained from rabbits and humans after unilateral nephrectomy (un i sera) compared with sera obtained preoperatively (control sera) sign ificantly stimulate H-3-thymidine incorporation into the DNA of cultur ed renal tissue from the respective species. In contrast, rabbit liver cells in culture are not stimulated by the uni sera compared with con trol sera obtained from rabbits. Mouse epidermal growth factor (EGF) a dded to tissue cultures significantly stimulates both kidney and liver cells of rabbits and kidney cells of humans. Antiserum against EGF ov ercomes, at least to some extent, the enhancing effect of EGF under al l circumstances, but does not influence the stimulatory ability of uni serum obtained from rabbit and human kidney cells from the respective species. In addition, the activity of EGF was not different in the pr esence of uni and control sera. This study corroborates the presence o f renotropic activity in the sera of rabbits and humans after removal of functioning renal mass and shows that this activity is not derived from EGF, nor does it work by potentiating some aspect of the EGF syst em.