| Abstract
| - The present studies were designed to assess the effect of uninephrectomy (UNX) on arterial pressure and renal excretory function in normal subjects. Baseline values of arterial pressure, renal function, parameters of the renin-angiotensin and renal kallikrein-kinin systems and the response to acute saline loading (VE, 1800 ml in 3 h) were estimated in 18 kidney donors prior to and 1 year following UNX. Within the follow-up period of 14±1 months mean arterial pressure (MAP) increased by 7±2 mmHg, creatinine clearance decreased by 38±4%, plasma renin activity (PRA) decreased, urinary kallikrein remained unchanged, and the renal response to VE was blunted. According to individual changes in MAP associated with UNX, subjects were classified as responders (R, increase in MAP≧10%, n=8) and non-responders (NR, n=10). Age, incidence of a family history of hypertension, decrease in creatinine clearance, and predonation PRA, urinary kallikrein, and the natriuretic response to VE were similar in the two groups. However, following UNX, PRA decreased whereas 24-h urinary sodium and thus sodium intake increased only in the R group. In conclusion, in normotensive subjects a 50% reduction in renal mass may result in a consistent increase in MAP and sometimes the development of de novo hypertension (4/18 subjects). Baseline characteristics as well as the predonation renal response to VE do not provide a means of detecting kidney donors in whom arterial pressure will increase consistently after UNX. The increase in MAP associated with UNX may result from a change in body sodium as indicated by the decline in PRA and the increase in sodium intake found in the R group.
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