Effects of sera from uninephrectomized rats on renal slices: PAH and TEA uptake and QO2.

We followed the effects of sera from unilaterally nephrectomized (uninephectomized) rats compared to sham-operated rats on 3H-p-aminohippurate (3H-PAH) and 14C-tetraethylammonium (14C-TEA) uptake and oxygen consumption (QO2) in incubating rat kidney slices. These studies were based on the assumption that a circulating renotropic substance might also influence various transport mechanisms. Sera were obtained at various times postoperation; the height of renotropic activity occurs 17-24 h after kidney extirpation. Sera removed 17-24 h postuninephrectomy significantly decreased both 3H-PAH and 14C-TEA uptake in incubating kidney slices. Similar to the inability to show significant renotropic activity after 36 h, sera obtained 48, 96, and 168 h postuninephrectomy had no significant influence on 3H-PAH and 14C-TEA uptake. Addition of sera (10% v/v) generally depressed QO2. However, sera obtained from uninephrectomized rats compared to sera from sham-operated rats had relatively more depressive effects on QO2 in renal tissue after 30 min of incubation (p less than 0.01). No significant differences in QO2 were seen when the uninephrectomized and sham-operated sera were added to the tissue immediately or after 60 min of incubation in the sera. These serum studies on 3H-PAH and 14C-TEA uptake simulate in many respects ones performed previously with serum from spontaneously hypertensive and salt-loaded rats and suggest the presence of a common circulating factor.