title: Inhibitory effect of natriuretic peptides on aldosterone synthase gene expression in cultured neonatal rat cardiocytes.
abstract: BACKGROUND
  Although previously thought to be synthesized solely in adrenal cortex, we have recently showed that aldosterone is also produced in and the expression of CYP11B2 mRNA was induced in the failing or hypertensive human ventricle. Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are cardiac hormones with wide biological effects, including inhibition of renin and aldosterone production. We hypothesized that natriuretic peptides reduce the expression of CYP11B2 mRNA in the heart.
  
  
  RESULTS
  To test this hypothesis, we examined whether endogenous or exogenous natriuretic peptides reduce the expression of CYP11B2 mRNA using real-time reverse transcription-polymerase chain reaction. By using HS 142-1, a functional guanylyl cyclase-A type receptor antagonist, we showed that angiotensin II (AngII) pretreated with HS 142-1 increased CYP11B2 mRNA expression (1.62+/-0.12-fold, HS 142-1+AngII 10(-7) mol/L versus AngII 10(-7) mol/L alone, P<0.0001). The treatment with exogenous (10(-6) mol/L) ANP and BNP reduced CYP11B2 mRNA expression (ANP, P=0.0042; BNP, P=0.0012).
  
  
  CONCLUSIONS
  We showed that endogenous and exogenous natriuretic peptides reduced CYP11B2 mRNA expression in cultured neonatal rat cardiocytes. This may inhibit the cardiac renin-angiotensin-aldosterone system by suppressing the gene expression of CYP11B2 and restraining cardiac hypertrophy and fibrosis.
authors.affiliation: Department of Cardiovascular Medicine, Kumamoto University School of Medicine, Kumamoto, Japan.
authors.forename: Teruhiko
authors.initials: T
authors.lastname: Ito
authors.forename: Michihiro
authors.initials: M
authors.lastname: Yoshimura
authors.forename: Shota
authors.initials: S
authors.lastname: Nakamura
authors.forename: Masafumi
authors.initials: M
authors.lastname: Nakayama
authors.forename: Yukio
authors.initials: Y
authors.lastname: Shimasaki
authors.forename: Eisaku
authors.initials: E
authors.lastname: Harada
authors.forename: Yuji
authors.initials: Y
authors.lastname: Mizuno
authors.forename: Megumi
authors.initials: M
authors.lastname: Yamamuro
authors.forename: Masaki
authors.initials: M
authors.lastname: Harada
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Saito
authors.forename: Kazuwa
authors.initials: K
authors.lastname: Nakao
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kurihara
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Yasue
authors.forename: Hisao
authors.initials: H
authors.lastname: Ogawa
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D002478:Cells, Cultured; D018920:Coculture Techniques; D006152:Cyclic GMP / Q000378:metabolism; D019405:Cytochrome P-450 CYP11B2 / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression / Q000187:drug effects*; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D020097:Natriuretic Peptide, Brain / Q000494:pharmacology*; D011134:Polysaccharides / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: C072551:HS 142-1; D011134:Polysaccharides; D012333:RNA, Messenger; D000804:Angiotensin II; D020097:Natriuretic Peptide, Brain; D009320:Atrial Natriuretic Factor; D019405:Cytochrome P-450 CYP11B2; D006152:Cyclic GMP