Changes in urinary retinol binding protein excretion and other indices of renal tubular damage in patients with non-insulin dependent diabetes.

Changes in urine retinol binding protein (RBP, M(r) 21,000) excretion and other indices of renal tubular damage were investigated in the patients with non-insulin dependent diabetes mellitus (NIDDM). Changes in urine RBP excretion were well paralleled with those of urine NAG excretion. In RBP-negative patients, the subjects with hypertension (systolic blood pressure > or = 140 mmHg or diastolic blood pressure > or = 90 mmHg) showed higher beta 2-microglobulin (beta 2-MG) excretion and albumin (Alb)/Cr ratios than normotensive ones. In addition, both urine beta 2-MG excretions and Alb/Cr ratios were significantly increased in RBP-positive patients. The measurement of urine RBP excretion may have an additional role in the diagnosis of renal tubular dysfunction in diabetic patients.