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Increased cardiac angiotensin converting enzyme expression in genetically hypertensive rats
J Mol
Cell
Cardiol
24 (Supplement
V) (1992)
October 1,192 Oral presentation Molecular and Genetic Changes in Cardiac Hypertrophy
II: 16.10 - 17.50
3
CARDIAC GROWTH FACTOR AND CtiALONE IN CARDIAC HYPERlROPHY Makato Nagano, Tadanari Ohkubo, Makato Nagai, Tohru Arino and Masahito Tsuchiya Department of Internal Medicine, AabD Hospital. The Jikei University School of Medicine, Tokyo, Japan Cardiac size can be regula&d by the balance in activity between cardiac growth factors and inhibiting factors. This study was under&ken to verify the role of cardiac grow-i% and inhibiting factors in the hypertrophied hearts of rats. For this purposethe hypertrophied hearts of Goldbl&t hypertension type I and I I rats were used. The supernatants of homogenized heart muscle were chrommgrsphied using the isoelectric focusing electrophoresis and HPLC methods. We examined the cardiac grow-th and inhibiting effects of the isolated proteins with cultured chicken embryonic cardiac myocytes. From the protein with isoelectric point 8.3 of hypertrophied rat hearts, 6 fractions with dmerent molecular weight were isolated. From these fractions, 5 protein fractions had active growth effects with hypertrophy and hyperplasia. The effect of these fractions was 10 times higher than Angiobsnsin I I on cardiac myocy-tes. The appearance of the cardiac growth factor reached a maximum level at 5-6 weeks after beginning of the cardiac hypertrophy. At this time, the cardiac chalones decreased which inhibited the growth of cardiac myocytes. The chalones were polyclonal proteins with isoelectric point 7.0-7.1.
154
REGULATION OF NYOSIN HEAVY CNAIN (NHC) GENE EXPRESSION IN CARDIAC HYPNRTROPHY: BPmm8 OF TE8To8TEEoNE AND CAnP I. Morano, *M. Kaling, tM. BGhm, ++A. Knorr, tE. Erdmann, *D. Ganten INF 326, and *German Institute for High Blood Pressure Research, INF Physiology II, 346, 6900 Heidelberg, tKlinikum Grofihadern, Medizinische Klinik I, 8000 Miinchen, ttDepartment of Pharmacology, Bayer AG, Leverkusen, Germany We demonstrated recently that testosterone caused cardiac hypertrophy and increased expression of both a-MHC mRNA and a-MHC isoenzymes (MORAN0 et al 1990, Circ. Res. 66: 1585-1590). To investigate the effect of testosterone on the transcriptional level the rat hepatoma cell line FTOLB was transiently transfected with a plasmid carrying part of the a-MHC gene promotor (-65 to -612) cloned in front of the chloramphenicol acetyl transferase (CAT) gene. When cotransfected with an androgen receptor plasmid, CAT activity rose 3.8-fold upon stimulation of the cells with DHwe investigated a-MHC isoenzyoe expression in the testosterone (lo-TM). Furthermore, rat left ventricle, adenylate cyclase (AC) activity of cardiac membrane fractions, of cardiac hypertrophy in several models of normotensive and and the degree experimentally and spontaneously hypertensive rats. We found statistically significant (p
212 INCREASED
CARDIAC ANGIOTENSIN CONVERTING ENZYME EXPRESSION IN GENETlCALLY HYPERTENSIVE RATS Reinhold Kreutzl, Maria S Fe andez-Alfonsol, Martin PaulI, Detlev Ganten2. IPharmakologisches .’ Centrum fiir Molekulare Medizii, Berlin-Buch. Institut, Universit%t Heidelberg. 9 Max _Delbruck Objective: Studies in the rat have demonstrated increased angiotensin converting enzyme (ACE) mRNA levels in left ventricular hypertrophy and cardiac failure. Furthermore, in genetic linkage studies the ACE gene has been identified as a possible candidate gene contributing to the high blood pressure in the stroke-prone spontaneously hypertensive rat (SHRSP) . We therefore investigated the left ventricular expression of ACE in SHRSP as compared to the normotensive Wistar-Kyoto (WKY) rats. Methods: In 4 weeks old male WKY and SHRSP rats ACE mRNA was measured by quantitative polymerase chain reaction. Results: Systolic (SBP) and diastolic (DBP) blood pressure were significant1 higher (p 5 0,Ol) in SHRSP (SBP: 140 f 3,l mmHg; DBP: 93,l f 3,9 mmHg) than in WKY rats rSBP: 107 f 3 mmHg; DBP: 66,7 f 3,6 mmHg). In addition, left ventricular weight was also significantly higher (p < 0,Ol) in SHRSP (4,2 f 0.08 mg/g tissue) when compared to WKY rats (3,75 + 0.09 mglg tissue), as well as the ACE expression, which was of 1,7 & 0,2 for WKY and of 2,6 + 0.2 for SHRSP. Conclusions: Our data demonstrate, that at an early hypertensive state with already detectable LVH, ACE mRNA levels are increased in SHRSP, suggesting a possible role of this gene in the development of cardiac growth. S.26
Cell
Cardiol
24 (Supplement
V) (1992)
October 1,192 Oral presentation Molecular and Genetic Changes in Cardiac Hypertrophy
II: 16.10 - 17.50
3
CARDIAC GROWTH FACTOR AND CtiALONE IN CARDIAC HYPERlROPHY Makato Nagano, Tadanari Ohkubo, Makato Nagai, Tohru Arino and Masahito Tsuchiya Department of Internal Medicine, AabD Hospital. The Jikei University School of Medicine, Tokyo, Japan Cardiac size can be regula&d by the balance in activity between cardiac growth factors and inhibiting factors. This study was under&ken to verify the role of cardiac grow-i% and inhibiting factors in the hypertrophied hearts of rats. For this purposethe hypertrophied hearts of Goldbl&t hypertension type I and I I rats were used. The supernatants of homogenized heart muscle were chrommgrsphied using the isoelectric focusing electrophoresis and HPLC methods. We examined the cardiac grow-th and inhibiting effects of the isolated proteins with cultured chicken embryonic cardiac myocytes. From the protein with isoelectric point 8.3 of hypertrophied rat hearts, 6 fractions with dmerent molecular weight were isolated. From these fractions, 5 protein fractions had active growth effects with hypertrophy and hyperplasia. The effect of these fractions was 10 times higher than Angiobsnsin I I on cardiac myocy-tes. The appearance of the cardiac growth factor reached a maximum level at 5-6 weeks after beginning of the cardiac hypertrophy. At this time, the cardiac chalones decreased which inhibited the growth of cardiac myocytes. The chalones were polyclonal proteins with isoelectric point 7.0-7.1.
154
REGULATION OF NYOSIN HEAVY CNAIN (NHC) GENE EXPRESSION IN CARDIAC HYPNRTROPHY: BPmm8 OF TE8To8TEEoNE AND CAnP I. Morano, *M. Kaling, tM. BGhm, ++A. Knorr, tE. Erdmann, *D. Ganten INF 326, and *German Institute for High Blood Pressure Research, INF Physiology II, 346, 6900 Heidelberg, tKlinikum Grofihadern, Medizinische Klinik I, 8000 Miinchen, ttDepartment of Pharmacology, Bayer AG, Leverkusen, Germany We demonstrated recently that testosterone caused cardiac hypertrophy and increased expression of both a-MHC mRNA and a-MHC isoenzymes (MORAN0 et al 1990, Circ. Res. 66: 1585-1590). To investigate the effect of testosterone on the transcriptional level the rat hepatoma cell line FTOLB was transiently transfected with a plasmid carrying part of the a-MHC gene promotor (-65 to -612) cloned in front of the chloramphenicol acetyl transferase (CAT) gene. When cotransfected with an androgen receptor plasmid, CAT activity rose 3.8-fold upon stimulation of the cells with DHwe investigated a-MHC isoenzyoe expression in the testosterone (lo-TM). Furthermore, rat left ventricle, adenylate cyclase (AC) activity of cardiac membrane fractions, of cardiac hypertrophy in several models of normotensive and and the degree experimentally and spontaneously hypertensive rats. We found statistically significant (p
212 INCREASED
CARDIAC ANGIOTENSIN CONVERTING ENZYME EXPRESSION IN GENETlCALLY HYPERTENSIVE RATS Reinhold Kreutzl, Maria S Fe andez-Alfonsol, Martin PaulI, Detlev Ganten2. IPharmakologisches .’ Centrum fiir Molekulare Medizii, Berlin-Buch. Institut, Universit%t Heidelberg. 9 Max _Delbruck Objective: Studies in the rat have demonstrated increased angiotensin converting enzyme (ACE) mRNA levels in left ventricular hypertrophy and cardiac failure. Furthermore, in genetic linkage studies the ACE gene has been identified as a possible candidate gene contributing to the high blood pressure in the stroke-prone spontaneously hypertensive rat (SHRSP) . We therefore investigated the left ventricular expression of ACE in SHRSP as compared to the normotensive Wistar-Kyoto (WKY) rats. Methods: In 4 weeks old male WKY and SHRSP rats ACE mRNA was measured by quantitative polymerase chain reaction. Results: Systolic (SBP) and diastolic (DBP) blood pressure were significant1 higher (p 5 0,Ol) in SHRSP (SBP: 140 f 3,l mmHg; DBP: 93,l f 3,9 mmHg) than in WKY rats rSBP: 107 f 3 mmHg; DBP: 66,7 f 3,6 mmHg). In addition, left ventricular weight was also significantly higher (p < 0,Ol) in SHRSP (4,2 f 0.08 mg/g tissue) when compared to WKY rats (3,75 + 0.09 mglg tissue), as well as the ACE expression, which was of 1,7 & 0,2 for WKY and of 2,6 + 0.2 for SHRSP. Conclusions: Our data demonstrate, that at an early hypertensive state with already detectable LVH, ACE mRNA levels are increased in SHRSP, suggesting a possible role of this gene in the development of cardiac growth. S.26