[Loss of renal functional reserve following kidney transplantation and in patients with advanced disorders of liver function].

Renal functional reserve capacity was evaluated in healthy controls, kidney transplant recipients and patients with impaired liver function by simultaneous measurements of periodic clearances of inulin, PAH and creatinine every 30 minutes before, during and after infusion of an amino acid (AA) solution. During AA infusion glomerular filtration rate rose in 10 healthy controls to about 35% above basal values (inulin clearance from 107 +/- 6 to 144 +/- 7 ml/min, p less than or equal to 0.0005), renal plasma flow increased by 27% (PAH clearance from 530 +/- 25 to 675 +/- 40 ml/min, p less than or equal to 0.002). 8 renal transplant recipients with good and stable renal function (creatinine clearance above 65 ml/min) showed no rise in GFR and RPF, as did 10 patients with severe impairment of liver function and normal basal kidney function (creatinine clearance above 100 ml/min). The lack of renal functional reserve in kidney transplant recipients might indicate a hyperfiltration of the transplanted kidney. This could affect the longtime prognosis of these patients. The liver seems to play a role in the mediation of the amino acid-induced rise of GFR, supporting the hypothesis of a putative liver hormone regulating GFR after protein ingestion or AA infusion.