Mitosis Stimulating Factor in Serum of Unilaterally Nephrectomized Rats.

Abstract

Renal epithelia of the outer medulla of rat kidney, cultured in vitro in a mixture of rat serum, obtained from a rat 2 days after unilateral nephrectomy, shows a mitotic index 4.64, as compared to 2.57 of controls with normal rat serum. This corresponds to the highest mitotic activity obtained in vivo. This suggests that approximately 2 days after uninephrectomy, a factor is present in the serum which stimulates mitosis. This mitosis stimulating factor was heat stable at 56[degree]C, non-dialyzable, organ specific, but not species specific. It is suggested that renal compensatory hypertrophy following uninephrectomy is a complicated phenomenon of primarily humoral co-ordination mediated by both the systemic stress mechanism and by a local growth regulatory mechanism.