L-arginine-induced vasodilation of the renal vasculature is not altered in hypertensive patients with type 2 diabetes.
OBJECTIVE
Diabetes, arterial hypertension, hypercholesterolemia, and aging are associated with endothelial dysfunction in various vasculatures. Endothelium-dependent vasodilation of the renal vasculature cannot be easily assessed, but infusion of L-arginine, the substrate of endothelial nitric oxide synthase, leads to an increase in renal plasma flow (RPF) in humans. We have examined the effect of L-arginine infusion on renal hemodynamics in hypertensive patients with type 2 diabetes.


METHODS
Twenty-three elderly patients with type 2 diabetes (age, 65 +/- 6 years; HbA(1c), 7.8 +/- 1.6%) with coexisting arterial hypertension (158 +/- 19/83 +/- 11 mmHg) and elevated cholesterol levels (total cholesterol, 215 +/- 33 mg/dl) were examined. These patients were compared with a young and healthy reference group (n = 20; age, 26 +/- 2 years). The effect of L-arginine infusion (100 mg/kg over 30 min) on RPF and glomerular filtration rate were measured using the constant input clearance technique with p-aminohippurate and inulin, respectively.


RESULTS
L-arginine infusion similarly influenced renal hemodynamics in patients and reference subjects: RPF increased by 7 +/- 11 and 7 +/- 11% in diabetic and reference subjects, respectively (P = NS). Other parameters of renal hemodynamics such as glomerular filtration rate (5 +/- 5 vs. 4 +/- 4%) and filtration fraction (-1 +/- 8 vs. -1 +/- 9%) were not significantly different between diabetic and reference subjects, too.


CONCLUSIONS
L-arginine-induced vasodilation of the renal vasculature is not different between a group of hypertensive diabetic patients and a young, healthy reference group. These data were obtained using low-dose L-arginine infusion.
Delles
Christian
C
Department of Medicine/Nephrology, University of Erlangen-Nürnberg, Nuremberg, Germany.
Schneider
Markus P
MP
Oehmer
Sebastian
S
Fleischmann
Erwin H
EH
Schmieder
Roland E
RE
D000368:Aged; D001120:Arginine / Q000008:administration & dosage / Q000494:pharmacology*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000503:physiopathology*; D005919:Glomerular Filtration Rate / Q000187:drug effects / Q000502:physiology; D006439:Hemodynamics / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000503:physiopathology*; D007262:Infusions, Intravenous; D007444:Inulin / Q000008:administration & dosage / Q000493:pharmacokinetics; D007668:Kidney / Q000187:drug effects / Q000502:physiology / Q000503:physiopathology; D008657:Metabolic Clearance Rate; D012016:Reference Values; D012039:Regional Blood Flow / Q000187:drug effects; D012079:Renal Circulation / Q000187:drug effects* / Q000502:physiology; D014664:Vasodilation / Q000187:drug effects*
D007444:Inulin; D001120:Arginine