Augmented expression of tissue endothelin-1 messenger RNA is a common feature in hypertensive rats.
Recent studies revealed important roles for endothelin-1 (ET-1) in the pathogenesis of hypertension. Whether ET-1 could be a primary cause of hypertension or a secondary factor associated with hypertension, however, remains unknown. In this study, we determined plasma ET-1 levels and the expression of ET-1 mRNA in tissues of rats rendered hypertensive using distinct mechanisms: deoxycorticosterone acetate (DOCA)-salt hypertension: N(G)-nitro-L-arginine-methyl ester- (L-NAME) induced hypertension; and spontaneously hypertensive rats (SHR-SP). ET-1 mRNA expression level was determined by reverse transcriptase polymerase chain reaction (RT-PCR) followed by Southern blotting. There was no significant difference in plasma ET-1 levels between the hypertensive rats and normotensive rats. By contrast, ET-1 mRNA level was significantly increased in various tissues including the adrenal, lung, kidney and brain of these hypertensive rats compared with control rats. Thus, ET-1 gene expression was ubiquitously augmented in tissues of hypertensive rats irrespective of the cause of the hypertension. The results suggest that the increase in ET-1 expression is not the primary cause of hypertension but a secondary outcome which may further exacerbate the hypertension.
Naruse
M
M
Department of Medicine, Institute of Clinical Endocrinology, Tokyo Women's Medical University, Japan. RXK00754@niftyserve.or.jp
Takagi
S
S
Tanabe
A
A
Naruse
K
K
Adachi
C
C
Yoshimoto
T
T
Seki
T
T
Takano
K
K
D000818:Animals; D019332:Endothelin-1 / Q000235:genetics*; D006973:Hypertension / Q000378:metabolism*; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D017208:Rats, Wistar
D019332:Endothelin-1; D012333:RNA, Messenger; D019331:NG-Nitroarginine Methyl Ester