Dysregulation of the endothelial nitric oxide synthase-soluble guanylate cyclase pathway is normalized by insulin in the aorta of diabetic rat.
Antiatherogenic effects of nitric oxide (NO) are mediated by activation of soluble guanylate cyclase (sGC) and are impaired by diabetes in animals and humans. We investigated whether uncontrolled diabetes and insulin therapy effect expression and function of the main enzymes of the endothelial nitric oxide (eNOS)-sGC signaling pathway in vivo. Expression and function of eNOS, sGC and protein kinase G (PKG) were studied by Western blot analysis and vasorelaxation to NO-donor in thoracic aortas from control (CON) and streptozotocin (SZT)-induced diabetic rats during uncontrolled diabetes (DM) and insulin treatment (INS) for 8 weeks. Protein level of eNOS was increased (+300%, P < 0.05), while sGC (-50%) and PKG (-65%) proteins were reduced (P < 0.03) in aortas of DM. Insulin treatment normalized these defects resulting in eNOS, sGC and PKG aortic protein content comparable to control. In aortic rings, diethylamine NONOate (DEA-NONOate)-induced vasorelaxation was attenuated (P< or =0.05) in DM compared to control and returned to normal in INS. Thus, experimental diabetes decreases sGC and PKG expression and their NO-dependent activation in aorta despite overexpression of eNOS. These abnormalities are normalized by insulin treatment and improved metabolic control.
Zanetti
Michela
M
Department of Clinical, Morphological and Technological Sciences-DSCMT, Clinica Medica, University of Trieste, Italy. zanetti@units.it
Barazzoni
Rocco
R
Stebel
Marco
M
Roder
Elena
E
Biolo
Gianni
G
Baralle
Francisco E
FE
Cattin
Luigi
L
Guarnieri
Gianfranco
G
D000818:Animals; D001013:Aorta, Thoracic / Q000201:enzymology*; D015153:Blotting, Western; D017869:Cyclic GMP-Dependent Protein Kinases / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000201:enzymology* / Q000503:physiopathology; D004789:Enzyme Activation; D006162:Guanylate Cyclase / Q000737:chemistry / Q000378:metabolism*; D006834:Hydrazines / Q000494:pharmacology; D066298:In Vitro Techniques; D007328:Insulin / Q000627:therapeutic use*; D008297:Male; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III; D009589:Nitrogen Oxides; D051381:Rats; D012995:Solubility; D014664:Vasodilation
D006834:Hydrazines; D007328:Insulin; D020030:Nitric Oxide Donors; D009589:Nitrogen Oxides; C084012:1,1-diethyl-2-hydroxy-2-nitrosohydrazine; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; C496316:Nos3 protein, rat; D017869:Cyclic GMP-Dependent Protein Kinases; D006162:Guanylate Cyclase