title: Role of stimulated intrarenal angiotensinogen in hypertension.
abstract: Experimental models of hypertension and patients with inappropriately increased renin formation due to a stenotic kidney, arteriosclerotic narrowing of the renal arterioles or a rare juxtaglomerular cell tumor have shown a progressive augmentation of the intrarenal/intratubular renin-angiotensin system (RAS). The increased intrarenal angiotensin II (Ang II) elicits renal vasoconstriction and enhanced tubular sodium reabsorption in proximal and distal nephron segments. The enhanced intrarenal Ang II levels are due to both increased Ang II type 1 (AT1) receptor mediated Ang II uptake and AT1 receptor dependent stimulation of renal angiotensinogen (AGT) mRNA and augmented AGT production. The increased AGT formation and secretion into the proximal tubular lumen leads to local formation of Ang II, which stimulates proximal transporters such as the sodium/hydrogen exchanger. Enhanced AGT production also leads to spillover of AGT into the distal nephron segments as reflected by AGT in the urine, which provides an index of intrarenal RAS activity. There is also increased Ang II concentration in distal nephron with stimulation of distal sodium transport. Increased urinary excretion of AGT has been demonstrated in patients with hypertension, type 1 and type 2 diabetes mellitus, and several types of chronic kidney diseases indicating an upregulation of intrarenal RAS activity.
authors.affiliation: Department of Physiology and the Hypertension and Renal Center of Excellence, Tulane University School of Medicine, New Orleans, LA 70112, USA.
authors.forename: Ryousuke
authors.initials: R
authors.lastname: Satou
authors.affiliation: Department of Physiology and the Hypertension and Renal Center of Excellence, Tulane University School of Medicine, New Orleans, LA 70112, USA.
authors.forename: Weijian
authors.initials: W
authors.lastname: Shao
authors.affiliation: Department of Physiology, Tulane University Health Sciences Center, SL39, 1430 Tulane Avenue, New Orleans, LA 70112, USA navar@tulane.edu.
authors.forename: L Gabriel
authors.initials: LG
authors.lastname: Navar
mesh_terms: D000804:Angiotensin II / Q000378:metabolism; D000808:Angiotensinogen / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport / Q000502:physiology; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D007674:Kidney Diseases / Q000503:physiopathology; D044140:Receptor, Angiotensin, Type 1 / Q000378:metabolism; D012083:Renin / Q000378:metabolism*; D012084:Renin-Angiotensin System / Q000502:physiology; D012964:Sodium / Q000378:metabolism; D014661:Vasoconstriction / Q000502:physiology
chemical_list: D044140:Receptor, Angiotensin, Type 1; D000808:Angiotensinogen; D000804:Angiotensin II; D012964:Sodium; D012083:Renin
keywords: AT1 receptor; angiotensin II; proximal tubule cells; sodium reabsorption