Elevation of an endogenous inhibitor of nitric oxide synthase in diabetic rat serum.
OBJECTIVE
To study the endogenous inhibitor of NO synthase NG,NG-dimethyl-arginine (DMA) in the diabetic rat serum.


METHODS
In streptozocin-induced diabetic rats, the serum DMA level and endothelium-dependent vasorelaxation to acetylcholine (ACh) were determined.


RESULTS
The serum DMA concentration was increased in the diabetic rats compared with their age-matched controls (5.4 +/- 1.0 vs 0.7 +/- 0.3 mumol.L-1, P < 0.01). The serum malondialdehyde (MDA) level was also increased in the diabetic rats compared with controls (2.5 +/- 0.3 vs 1.5 +/- 0.1 mumol.L-1, P < 0.01). Vasodilator response to ACh was impaired in diabetic thoracic aortas, which was improved by preincubation with L-arginine 1 mmol.L-1.


CONCLUSIONS
Hyperglycemia elevated the endogenous DMA content, which contributed to attenuated endothelium-dependent vasorelaxation in streptozocin-induced diabetic rats.
D000818:Animals; D001011:Aorta / Q000502:physiology; D001120:Arginine / Q000031:analogs & derivatives* / Q000097:blood; D003921:Diabetes Mellitus, Experimental / Q000097:blood* / Q000503:physiopathology; D004791:Enzyme Inhibitors / Q000097:blood; D008297:Male; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D052250:Nitric Oxide Synthase Type III; D051381:Rats; D017207:Rats, Sprague-Dawley; D014664:Vasodilation