Atrial natriuretic peptide (
ANP) plays a major role in
electrolyte and volume homeostasis through potent
biological effects including vasorelaxation, bronchorelaxation, lung permeability, and clearance. There are two distinct biochemical and functional classes of
ANP receptors,
guanylate cyclase receptor (GC-R) and clearance receptors (clearance-R). Two subtypes of GC-R have been described, GCA-R and GCB-R. Antenatal
glucocorticoid therapy (AGT) has been demonstrated to improve pulmonary immaturity and abnormal structure of pulmonary arteries in animal models of
congenital diaphragmatic hernia (CDH). The aim of this study was to investigate the effect of antenatal
glucocorticoid administration on the
ANP system in
nitrofen-induced CDH hypoplastic lung in rats. A CDH model was induced in pregnant rats following administration of
nitrofen on day 9.5 of gestation.
Dexamethasone (Dex) was given intraperitoneally on days 18.5 and 19.5;
cesarean section was performed on day 21. Reverse transcription polymerase chain reaction was performed to evaluate the relative amounts of GCA-R, GCB-R and clearance-R
mRNA expression. The
mRNA expression of GCA-R, GCB-R, and clearance-R was significantly increased in CDH compared to control lung.
ANP receptor mRNA expression was significantly decreased in CDH lung with compared to without Dex treatment. Our finding of increased
ANP receptor mRNA expression in CDH lung suggests that the hypoplastic lung has high sensitivity for
ANP. Decreased
mRNA expression of
ANP receptors in CDH lung after Dex treatment suggests that AGT may improve pulmonary physiological function of
ANP in hypoplastic CDH lung.