title: Hypoxia reduces atrial natriuretic peptide clearance receptor gene expression in ANP knockout mice.
abstract: We tested the hypotheses that hypoxic exposure is associated with exacerbated pulmonary hypertension and right ventricular (RV) enlargement, reduced atrial natriuretic peptide (ANP) clearance receptor (NPR-C) expression, and enhanced B-type natriuretic peptide (BNP) expression in the absence of ANP. Male wild-type [ANP(+/+)], heterozygous [ANP(+/-)], and homozygous [ANP(-/-)] mice were studied after a 5-wk hypoxic exposure (10% O(2)). Hypoxia increased RV ANP mRNA and plasma ANP levels only in ANP(+/+) and ANP(+/-) mice. Hypoxia-induced increases in RV pressure were significantly greater in ANP(-/-) than in ANP(+/+) or ANP(+/-) mice (104 +/- 17 vs. 45 +/- 10 and 63 +/- 7%, respectively) as were increases in RV mass (38 +/- 4 vs. 26 +/- 5 and 29 +/- 4%, respectively). NPR-C mRNA levels were greatly reduced in the kidney, lung, and brain by hypoxia in all three genotypes. RV BNP mRNA and lung and kidney cGMP levels were increased in hypoxic mice. These findings indicate that disrupted ANP expression worsens hypoxic pulmonary hypertension and RV enlargement but does not alter hypoxia-induced decreases in NPR-C and suggest that compensatory increases in BNP expression occur in the absence of ANP.
authors.affiliation: Vascular Biology and Hypertension Program, Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.
authors.forename: J Z
authors.initials: JZ
authors.lastname: Sun
authors.forename: S J
authors.initials: SJ
authors.lastname: Chen
authors.forename: G
authors.initials: G
authors.lastname: Li
authors.forename: Y F
authors.initials: YF
authors.lastname: Chen
mesh_terms: D000818:Animals; D009320:Atrial Natriuretic Factor / Q000097:blood / Q000172:deficiency* / Q000235:genetics / Q000502:physiology; D001794:Blood Pressure; D001921:Brain / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects*; D006162:Guanylate Cyclase / Q000235:genetics*; D006352:Heart Ventricles; D000860:Hypoxia / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism; D008168:Lung / Q000378:metabolism; D008297:Male; D051379:Mice; D018345:Mice, Knockout / Q000235:genetics; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism; D017461:Receptors, Atrial Natriuretic Factor / Q000235:genetics*; D012016:Reference Values; D016278:Ventricular Function, Right
chemical_list: D012333:RNA, Messenger; D009320:Atrial Natriuretic Factor; D006162:Guanylate Cyclase; D017461:Receptors, Atrial Natriuretic Factor; C073616:atrial natriuretic factor receptor C