Acute reduction of arterial blood pressure reduces urinary albumin excretion in type 1 (insulin-dependent) diabetic patients with incipient nephropathy.
The effect of an acute reduction in arterial blood pressure upon kidney function was studied in 12 patients with Type 1 (insulin-dependent) diabetes and incipient nephropathy (persistent microalbuminuria). Renal function was assessed by measurement of the glomerular filtration rate (single bolus 51Cr-EDTA technique) and by the urinary albumin excretion rate (radioimmunoassay). The study was performed twice within 2 weeks, with the patients receiving a slow intravenous injection of either clonidine (225 micrograms) or saline (154 mmol/l) in random order. Clonidine reduced arterial blood pressure from 125/79 +/- 13/8 to 104/68 +/- 9/7 mmHg (p less than 0.01), urinary albumin excretion rate from 68 (31-369) to 46 (6-200) micrograms/min (median and range) (p less than 0.01), and fractional clearance of albumin in all patients (median 29%) (p less than 0.01). Glomerular filtration rate was 110 +/- 11 before and 106 +/- 13 ml/min/1.73 m2 after clonidine injection. The blood glucose concentration was 15 +/- 4 mmol/l before and 14 +/- 5 mmol/l after clonidine injection. In agreement with findings in animal studies, our results suggest that microalbuminuria is to a large extent pressure-dependent, probably because of glomerular hypertension, and that autoregulation of glomerular filtration rate is normal in most patients with incipient diabetic nephropathy.
Hommel
E
E
Mathiesen
E
E
Edsberg
B
B
Bahnsen
M
M
Parving
H H
HH
D000328:Adult; D000419:Albuminuria / Q000209:etiology / Q000517:prevention & control*; D001794:Blood Pressure / Q000187:drug effects*; D003000:Clonidine / Q000627:therapeutic use*; D003922:Diabetes Mellitus, Type 1 / Q000628:therapy*; D003928:Diabetic Nephropathies / Q000209:etiology / Q000517:prevention & control*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D008875:Middle Aged
D003000:Clonidine