Kidney function, like the function of other organs, is dynamic and continuously adjusts to
changes in the internal environment to maintain homeostasis. The glomerular filtration rate,
which serves as the primary index of kidney function in clinical practice, increases in
response to various physiological and pathological stressors including oral protein intake.
The difference between the glomerular filtration rate in the resting state and at maximum
capacity has been termed renal functional reserve (RFR). RFR could provide additional …