The interrelationship between TGF-beta1 and nitric oxide is altered in salt-sensitive hypertension.
The study of salt-sensitive hypertension has been facilitated by development of genetic models, especially the Dahl/Rapp salt-sensitive (S) rat. S rats rapidly become hypertensive after initiation of a diet containing 8.0% NaCl and subsequently develop arteriolonephrosclerosis and renal failure, whereas the salt-resistant (R) strain remains normotensive on the same diet. The purpose of the present study was to use these strains to demonstrate the interactions between transforming growth factor-beta1 (TGF-beta1) and nitric oxide (NO). Young, male S and R rats were fed for 4 days diets that contained either 0.3 or 8.0% NaCl. An increase in dietary salt increased kinase activities of both p38 MAPK and p42/44 MAPK in cytoplasmic extracts from aortic rings and isolated glomeruli from both strains. Inhibition of either pathway with PD-098059 or SB-203580 decreased production of TGF-beta1 and nitrate plus nitrite (NOx). In both strains, production of active TGF-beta1 and NOx linearly correlated. Incubation of aortic rings and isolated glomeruli with the NO donor NOR3 decreased TGF-beta1 levels, whereas the NO synthase inhibitor Nomega-nitro-l-arginine methyl ester increased production. The inhibitory effect of NO on production of TGF-beta1 was reduced in preparations from S rats. Although a close interrelationship existed between TGF-beta1 and NO in both strains, production of TGF-beta1 was increased in prehypertensive S rats and was further exaggerated with the increase in dietary salt intake. Augmented vascular and glomerular production of TGF-beta1 and diminished NO may contribute to the development of hypertensive nephrosclerosis in S rats.
Ying
Wei-Zhong
WZ
Nephrology Research and Training Center, Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham 35294-0007, USA.
Sanders
Paul W
PW
D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006973:Hypertension / Q000209:etiology* / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009566:Nitrates / Q000037:antagonists & inhibitors / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D009573:Nitrites / Q000037:antagonists & inhibitors / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D051381:Rats; D020303:Rats, Inbred Dahl; D012694:Serine / Q000378:metabolism; D017673:Sodium Chloride, Dietary / Q000008:administration & dosage / Q000009:adverse effects*; D016212:Transforming Growth Factor beta / Q000008:administration & dosage / Q000378:metabolism*; D053773:Transforming Growth Factor beta1; D048051:p38 Mitogen-Activated Protein Kinases
D004791:Enzyme Inhibitors; D009566:Nitrates; D009573:Nitrites; D017673:Sodium Chloride, Dietary; C508962:Tgfb1 protein, rat; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D009569:Nitric Oxide; D012694:Serine; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases