Atrial natriuretic factor, angiotensin II, aldosterone, arginine vasopressin and urinary prostaglandin E₂ excretion in hyperfiltrating unilaterally nephrectomized humans

Abstract

To investigate the degree to which long-term adaptive changes in the remaining kidney after unilateral nephrectomy are dependent on hormonal factors, we measured resting plasma levels of atrial natriuretic factor (ANF), angiotensin II (Ang II), aldosterone (Aldo), arginine vasopressin (AVP), urinary excretion of prostaglandin E₂ (UPGE₂), creatinine clearance, and fractional sodium excretion (FE_N;1) in 11 unilaterally nephrectomized persons (UNP) 1-11 years after operation and in 13 control subjects (study 1). Additionally, to investigate whether the remnant kidney's ability to excrete an acute sodium load is dependent on hormonal changes, Ang II, Aldo, AVP, sodium excretion, UPGE₂, and free-water reabsorption (TCH₂) were measured in response to acute intravenous sodium loading in nine UNP and 14 controls (study 2). Study 1 showed that UNP exhibited hyperfiltration compared with controls (creatinine clearance 79 ml/min/1.73 m2/kidney vs 53, p<0.01) and increased FE_Na (0.82% vs 0.58, p<0.01). Despite this, ANF, Ang II, Aldo, and AVP did not deviate significantly from controls. UPGE₂ was increased in UNP compared with controls (108 ng/24 h/kidney vs 64, p<0.01). Study 2 showed that UNP exhibited a normal natriuretic response but an exaggerated increase in TCH_2O (6.0 ml/ min/kidney vs 3.9, p<0.02). However, the response in plasma levels of Ang II, Aldo and AVP was the same in UNP and in controls.

We conclude that the long-term adaptation in the remaining kidney after unilateral nephrectomy does not involve any major changes in ANF, Ang II, Aldo, or AVP. The increase in PGE₂ may be a compensatory phenomenon that tends to preserve renal function.

Key Words:

• free-water reabsorption
• glomerular filtration rate
• nephrectomy
• renal function
• sodium