Atrial natriuretic peptide expression in rats with different pulmonary hypertensive responses to hypoxia.
Mechanisms that regulate atrial natriuretic peptide (ANP) expression during hypoxia are not well defined. We hypothesized that plasma immunoreactive ANP (irANP) and right heart irANP and ANP mRNA levels would be greater in a strain of Sprague-Dawley rats that develops more severe hypoxic pulmonary hypertension (H rats) than another strain (M rats). After 3 wk of hypoxia (0.5 atm), right ventricular systolic pressure (RVSP) and the right ventricle (RV) weight-to-left ventricle plus septum (LV (+) S) weight ratio [RV/(LV+S)] were greater in H rats than in M rats (70 +/- 4 vs. 40 +/- 2 mmHg and 0.59 +/- 0.02 vs. 0.50 +/- 0.02, respectively; P < 0.05 for both), but plasma ANP increased twofold and RV irANP and ANP mRNA increased fivefold in both rat strains. After 3 days of normoxic recovery from chronic hypoxia, RVSP, RV/(LV+S), and RV irANP and ANP mRNA levels decreased in M rats but not in H rats. Plasma irANP decreased to baseline levels in both rat strains. We conclude that, in addition to changes in RV pressure and hypertrophy, hypoxia acts through other mechanisms to modulate RV ANP synthesis and circulating ANP levels in hypoxia-adapted rats.
Klinger
J R
JR
Division of Pulmonary and Critical Care Medicine, Rhode Island Hospital, Providence, USA.
Wrenn
D S
DS
Warburton
R R
RR
Pietras
L
L
Ou
L C
LC
Hill
N S
NS
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000096:biosynthesis* / Q000097:blood; D001835:Body Weight; D006321:Heart / Q000503:physiopathology*; D006325:Heart Atria; D006352:Heart Ventricles; D006976:Hypertension, Pulmonary / Q000097:blood / Q000209:etiology / Q000503:physiopathology*; D000860:Hypoxia / Q000503:physiopathology*; D008297:Male; D009206:Myocardium / Q000378:metabolism; D009929:Organ Size; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D013045:Species Specificity; D013599:Systole; D013997:Time Factors; D014158:Transcription, Genetic; D016277:Ventricular Function, Left; D016278:Ventricular Function, Right
D012333:RNA, Messenger; D009320:Atrial Natriuretic Factor