[Changes of mitogen-activated protein kinase activity in cardiac tissues, Ang II and cardiac hypertrophy in spontaneously hypertensive rats].
Mitogen-activated protein kinases (MAPKs) are thought to be critical components in signal transduction pathways in regulation of cell growth and differentiation. The purpose of the present investigation is to study possible involvement of MAPKs in the progress of cardiac hypertrophy in spontaneously hypertensive rats (SHRs) and effects of age on Angiotensin II (Ang II), MAPK activity and cardiac hypertrophy. The animals were divided into three groups: 4 months old WKY rats (n = 8), 4 month old SHRs (n = 8) and 15 month old SHRs (n = 6). Ratio of heart to body weight was measured. Ang II was determined by RIA. MAPK activity in cardiac tissue was assayed by the "in-gel" myelin basic protein phosphorylation. The results show that in comparison with 4 month old WKY rats, Ang II in plasma and cardiac tissues were elevated (216.4%, P < 0.01; 101.2%, P < 0.01) in 4 months old SHRs, while the MAPK activity was increased 107.0% (P < 0.01) with a parallel cardiac hypertrophy (P < 0.01). In comparison with 4 month old SHRs, Ang II and MAPK activity in cardiac tissue of the 15 months old SHRs were decreased (31.3%, P < 0.01; 29.7%, P < 0.05) but the cardiac hypertrophy increased by 38.5% (P < 0.01). MAPK may be involved in the progress of cardiac hypetrophy in SHR and the increased MAPK activity may be partly induced by Ang II.
He
K L
KL
Department of Cardio-Nephrology, General Hospital of PLA, Beijing 100853.
Zheng
Q F
QF
Mu
S C
SC
Li
T C
TC
Pang
Y Z
YZ
Tang
C S
CS
D000804:Angiotensin II / Q000378:metabolism*; D000818:Animals; D006332:Cardiomegaly / Q000209:etiology / Q000378:metabolism*; D006973:Hypertension / Q000150:complications / Q000503:physiopathology*; D066298:In Vitro Techniques; D008297:Male; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY
D000804:Angiotensin II; D020928:Mitogen-Activated Protein Kinases