Influence of nephrectomy on the growth of a murine Wilms tumor: a study using parabiotic rats

It has been reported that unilateral nephrectomy causes acceleration of the growth of a Wistar/Furth rat Wilms tumor. We studied this phenomenon in parabiotic rats by measuring tumor growth after either sham nephrectomy, or excision of 1, 2 or 3 kidneys. We observed no stimulation of tumor growth in the experimental groups. Renal function was significantly decreased after removal of 2 or 3 kidneys. Serum creatinine levels were significantly different between right and left members of parabiotic pairs in these 2 groups. The effect of unilateral and bilateral nephrectomy on tumor growth in single rats also was examined. In these rats progressive increases in tumor growth were observed after unilateral and bilateral nephrectomy. Our inability to demonstrate a tumor-stimulating factor in the parabiotic model may be due partly to incomplete sharing of humoral factors between parabionts. Serum transfer studies in vitro may prove more fruitful in demonstrating such a factor.