Augmentation of BNP gene expression in atria by pressure overload in transgenic rats harbouring human renin and angiotensinogen genes.
We studied the role of angiotensin II in pressure overload-induced B-type natriuretic peptide (BNP) gene expression by using a double transgenic rat (dTGR) model, in which transgenic rats for the human angiotensinogen and renin genes are crossed. Pressure overload produced by [Arg8]-vasopressin (AVP) infusion (i.v., 0.05 microg/kg/min for 2 h) in conscious, chronically instrumented rats, resulted in a significantly greater increase in BNP mRNA levels in the left atrium of the dTGR rats than in Sprague-Dawley (SD) control rats (3.6- vs 1.6-fold, p < 0.05), while in the left ventricle there was no significant difference between the strains. In dTGR rats, the early activation of the BNP gene expression was associated with a decrease in immunoreactive BNP levels in the atrium (27.5%, p < 0.05), but not in the ventricle. In SD rats, ir-BNP levels did not change significantly in either atria or ventricles in response to AVP infusion. These results show that the pressure overload-induced activation of BNP gene expression differs between atrial and ventricular myocytes in the dTGR model of experimental hypertension.
Marttila
M
M
Department of Pharmacology and Toxicology, Biocenter Oulu, University of Oulu, Finland.
Puhakka
J
J
Luodonpää
M
M
Vuolteenaho
O
O
Ganten
U
U
Ruskoaho
H
H
D000808:Angiotensinogen / Q000235:genetics*; D000818:Animals; D030801:Animals, Genetically Modified; D009320:Atrial Natriuretic Factor / Q000235:genetics* / Q000378:metabolism; D001794:Blood Pressure / Q000235:genetics / Q000502:physiology; D004195:Disease Models, Animal; D015870:Gene Expression; D006325:Heart Atria / Q000378:metabolism; D006801:Humans; D006973:Hypertension / Q000235:genetics* / Q000503:physiopathology; D008297:Male; D020097:Natriuretic Peptide, Brain; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012083:Renin / Q000235:genetics*
D012333:RNA, Messenger; D000808:Angiotensinogen; D020097:Natriuretic Peptide, Brain; D009320:Atrial Natriuretic Factor; D012083:Renin