Objective To evaluate the changes of glomerular filtration rate (GFR), effective renal plasma flow (ERPF) and microalbuminuria in early diabetic nephropathy (DN) and their correlation.

Methods Examined renal tubular function and glomerular filtration function in essential hypertension, after excluded renal hypertension by renal artery angiography and creatinine clearance.

Renal clearance is used to determine renal elimination mechanisms of a drug, which is the result of glomerular filtration, active tubular secretion and reabsorption.