The effect of low-dose dopamine on renal function in uninephrectomized patients: special emphasis on kidney donors before and after nephrectomy.

In rats, uninephrectomy and subtotal renal ablation result in the development of hypertension and proteinuria, and, in a progressively downhill course of renal function, to end-stage renal disease. These events are attributed to glomerular hyperfiltration of remnant glomeruli. In man, however, long-term effects of unilateral nephrectomy appear to be less disastrous. The infusion of a low dose of dopamine (1.5-2.0 micrograms/kg/min) can be used to test the presence of a reserve filtration capacity i.e., the absence or existence of glomerular hyperfiltration. In order to investigate whether in man glomerular hyperfiltration occurs after unilateral nephrectomy, the effects of low-dose dopamine on glomerular filtration rate (clearance of 125I-iothalamate) and effective renal plasma flow (clearance of 131I-hippurate) of 18 uninephrectomized patients were investigated and compared with the effects of low-dose dopamine on those parameters of 32 healthy volunteers. Special interest was given to a subgroup of 10 kidney donors who were investigated before and after nephrectomy. Median values for the percentage of a dopamine-induced rise in the glomerular filtration rate were 4.5% in the uninephrectomized subjects and 10.0% in the control subjects (p less than 0.01). Median dopamine-induced increase in effective renal plasma flow as 22.5% and 35.0%, respectively (p less than 0.01). In the kidney donors the median percentage of a dopamine-induced change in the glomerular filtration rate was 12.4% before and 5.9% after nephrectomy (p less than 0.05%). It is concluded firstly, that renal reserve filtration capacity is decreased after unilateral nephrectomy.(ABSTRACT TRUNCATED AT 250 WORDS)