Compensatory renal growth: interactions of nephrectomy serum and urine antisera leading to a new theory of renal growth regulation.

Compensatory renal growth is mediated by a substance(s) found in the serum and in urine called renotropin. The interaction of nephrectomy serum and urine antisera upon compensatory renal growth was investigated by administering rat uninephrectomy serum and sham serum and urine to rabbits. The rabbit antisera was given intravenously to uninephrectomy and sham operated rats and kidney weight/body weight ratios were calculated. Antisera against sham serum and urine induced kidney growth as well as antisera against uninephrectomy serum and urine given to sham animals. These results suggest the presence of a circulating antigenic inhibitor to kidney growth and suggest that renotropin is made up of a inhibitory as well as a stimulatory substance.