Korean J Physiol Pharmacol.
1997 Feb;1(1):55-63.
Renal mRNA expression of renin, AT-1 receptor, TGF-beta-1 and
fibronectin in obstructive nephropathy
- Affiliations
-
- 1
Department of Physiology, School of Medicine, Kyungpook National University,
Taegu 700-422 South Korea.
Abstract
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The present study was designed to quantify the alterations of renal
renin, angiotensin type I receptor (AT-1), TGF-beta-1, and fibronectin
gene expression in rats with unilateral ureteral obstruction (UUO). We
also investigated the change of AT-1 density during UUO. Reverse
transcription-polymerase chain reaction (RT-PCR) technique and receptor
binding assay were used to detect mRNA expression and receptor density,
respectively. At one day after UUO, renin mRNA level of the obstructed
kidneys was decreased transiently and then subsequently increased to
the level of sham kidneys. In the contralateral kidneys of the same
rats, on the contrary, renin mRNA level was gradually decreased. Then,
at 9 days after UUO, it was significantly lower than that of sham
kidneys. The expressions of both AT-1 subtypes, called AT-1A and AT-1B,
mRNAs did not change at any time. UUO led to a significant decrease in
AT-1 density in the obstructed kidneys compared with the sham kidneys
at 1 and 3 days (66 +/- 11.6% (p lt 0.05) and 73 +/- 4.0% (p lt 0.01),
respectively). Thereafter, AT-1 density was gradually increased and at
9 days it showed a marked elevation in the obstructed kidneys compared
to the sham kidneys. In contrast, in the contralateral kidneys AT-1
density was significantly reduced from 3 to 9 days after UUO. The
TGF-beta-1 m-RNA level of the obstructed kidneys was unexpectedly
decreased at 6 days after UUO. Then, at 9 days it was followed by a
significant increase in the obstructed kidneys, whereas it showed an
obvious decrease in the contralateral kidneys. In addition, fibronectin
mRNA level was also significantly increased in the obstructed kidneys
after UUO compared to the sham or the contralateral kidneys of the same
rats. These results suggest a differential regulation of renal renin,
AT-1 receptor, TGF-beta-1 and fibronectin mRNA levels at different
stages of UUO.