Tonin in rat heart with experimental hypertrophy.
The present study was undertaken to determine tonin expression and activity in rat heart presenting isoproterenol-induced hypertrophy. Renin, angiotensin-converting enzyme (ACE), and angiotensinogen (AG) expression were also determined. Wistar rats were treated with isoproterenol for 7 days (5 mg x kg(-1) x day(-1) sc). For untreated animals, the levels of tonin-specific activity in the atrium were 2.6- and 5.5-fold higher than those of the left and right ventricle, respectively. After treatment, the levels of tonin-specific activity increased twofold in the atrium but did not change in the ventricles. Renin expression was not detectable in these structures, and ACE expression levels did not change with treatment. AG expression was detected in the left ventricle at very low levels compared with the atrium and increased significantly only in the hypertrophied atrium (1.8-fold). Tonin mRNA was not detected in the ventricle but was found at low levels in the atrium, which increased after isoproterenol treatment. Our results permit us to conclude that tonin may play a role in the process of heart hypertrophy in the rat.
Borges
Julio Cesar
JC
Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Brazil. jlpesq@icb.ufmg.br
Silva
José Antônio
JA
Gomes
Maria Aparecida
MA
Lomez
Eliane Sa Lopes
ES
Leite
Katia Moraes
KM
Araujo
Ronaldo Carvalho
RC
Bader
Michael
M
Pesquero
João Bosco
JB
Pesquero
Jorge Luiz
JL
D000318:Adrenergic beta-Agonists; D000804:Angiotensin II / Q000096:biosynthesis; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000096:biosynthesis; D006332:Cardiomegaly / Q000139:chemically induced / Q000378:metabolism*; D018450:Disease Progression; D005786:Gene Expression Regulation; D007545:Isoproterenol; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D009929:Organ Size / Q000187:drug effects; D015347:RNA Probes; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020840:Tissue Kallikreins / Q000096:biosynthesis / Q000378:metabolism*
D000318:Adrenergic beta-Agonists; D015347:RNA Probes; D000804:Angiotensin II; D009320:Atrial Natriuretic Factor; C117017:tonin; D020840:Tissue Kallikreins; D007545:Isoproterenol