Upregulation of endothelial nitric oxide synthase in rat aorta after ingestion of fish oil-rich diet.
A previous study with aortic segments isolated from rats fed a fish oil-rich diet indicated an increase in acetylcholine-induced nitric oxide (.NO)-mediated relaxation. However, it remained to be elucidated whether a fish oil-rich diet affects the vascular activity per se and the point of the.NO-cGMP pathway at which fish oil acts. For this purpose, two groups of Sprague-Dawley rats were fed a semipurified diet containing 5% lipids, either corn oil (CO) or menhaden oil (MO), for 8 wk. We studied the mRNA and protein levels of endothelial NO synthase (eNOS) and NOS activity. The bioavailability of vascular.NO was assessed directly by electron spin resonance spectroscopy. The levels of cGMP, l-arginine, and l-citrulline were also evaluated in homogenates. Superoxide anion (O(2)(-).) production and related antioxidant activities were also studied in aortic segments. The aortic content of eNOS mRNA was increased in rats fed the MO-rich diet. This resulted in increases in both eNOS protein levels (70% relative to the rats fed the CO-rich diet) and NOS activity (102%);.NO production increased by 90%, cGMP levels increased by 100%, and l-arginine decreased by 30%. No change in aortic O(2)(-). production was caused by dietary MO. The upregulation of the eNOS-cGMP pathway induced by dietary MO may contribute to the maintenance of vascular homeostasis and explain its beneficial effect in the prevention of arterial diseases.
López
Diego
D
Departament de Fisiologia, Facultat de Biologia, Universitat de Barcelona, E-08028 Barcelona, Spain.
Orta
Xavier
X
Casós
Kelly
K
Sáiz
M Puy
MP
Puig-Parellada
Pere
P
Farriol
Mireia
M
Mitjavila
M Teresa
MT
D000818:Animals; D001011:Aorta / Q000201:enzymology* / Q000378:metabolism; D001120:Arginine / Q000378:metabolism; D002956:Citrulline / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D004578:Electron Spin Resonance Spectroscopy; D005395:Fish Oils / Q000008:administration & dosage*; D008297:Male; D009569:Nitric Oxide / Q000096:biosynthesis; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III; D010088:Oxidoreductases / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013481:Superoxides / Q000378:metabolism; D015854:Up-Regulation
D004042:Dietary Fats, Unsaturated; D005395:Fish Oils; D012333:RNA, Messenger; D013481:Superoxides; D002956:Citrulline; D009569:Nitric Oxide; D001120:Arginine; D010088:Oxidoreductases; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; C496316:Nos3 protein, rat; D006152:Cyclic GMP