title: Effect of posture and acute glycaemic control on the excretion of retinol-binding protein in normoalbuminuric insulin-dependent diabetic patients.
abstract: 1. It has been suggested that tubular damage may precede glomerular damage at the onset of diabetic nephropathy. This may be reflected by increased urinary excretion of low-molecular-mass proteins, such as retinol-binding protein. 2. We have measured the urinary excretion rate of retinol-binding protein overnight, during orthostasis and during a hyperinsulinaemic euglycaemic clamp (blood glucose concentration 7.0 mmol/l) with stable diuresis in 34 normotensive, normoalbuminuric insulin-dependent diabetic patients and in 10 normal control subjects. Normal control subjects were not clamped. A further four normoalbuminuric insulin-dependent diabetic patients were rendered euglycaemic without a water load. 3. Overnight retinol-binding protein excretion rate was 58 (16-157) [median(range)] ng/min in patients with insulin-dependent diabetes and 32 (15-72) ng/min in control subjects (P < 0.01). The excretion rate did not change during orthostasis [patients with insulin-dependent diabetes, 67 (3-173) ng/min; control subjects, 23 (5-78) ng/min]. During the euglycaemic clamp retinol-binding protein excretion rate increased to 383 (78-4897) ng/min in patients with insulin-dependent diabetes (P < 0.01). An average increment in retinol-binding protein excretion rate of greater than 4000% was noted after acute euglycaemia in those patients with insulin-dependent diabetes who were not water-loaded. 4. In insulin-dependent diabetes, both overnight and orthostatic retinal-binding protein excretion was not correlated with fasting blood glucose concentration, HbA1, fructosamine or duration of diabetes. The absolute and incremental excretion rates of retinol-binding protein during the clamp were, however, correlated with both fasting blood glucose concentration and glucose excretion rate (rs = 0.41-0.48, P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
authors: Department of Medicine, Medical School, University of Newcastle upon Tyne, U.K.
authors: C
authors: C
authors: Catalano
authors: P H
authors: PH
authors: Winocour
authors: S
authors: S
authors: Gillespie
authors: I
authors: I
authors: Gibb
authors: K G
authors: KG
authors: Alberti
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D003922:Diabetes Mellitus, Type 1 / Q000378:metabolism* / Q000652:urine; D005260:Female; D006801:Humans; D007684:Kidney Tubules / Q000378:metabolism; D008297:Male; D011187:Posture / Q000502:physiology*; D012177:Retinol-Binding Proteins / Q000652:urine*; D054840:Retinol-Binding Proteins, Cellular
chemical_list: D001786:Blood Glucose; D012177:Retinol-Binding Proteins; D054840:Retinol-Binding Proteins, Cellular