Objective To detect the renal reserve in senility and deduce the clinic significance.Methods The glomerular filtration rate and filtration fraction were measured in 43 healthy citizens before and after infusion 18-amino acid to investigate the renal functional reserve.Results Before infusion the amino acid,the range of GFR basal value of senile persons was(58～101)ml/min 1.73m 2 mean value was(76?8.5)ml/min 1.73m 2.And after the amino acid infusion,the GFR value was (65～128)ml/min 1.73m 2,mean value was (103?8.1)ml/min 1.73m 2,there was obviously elevation (P