Wolf, Konrad and Castrop, Hayo and Hartner, Andrea and Goppelt-Struebe, Margarete and Hilgers, Karl F. and Kurtz, Armin (1999) Inhibition of the renin-angiotensin system upregulates cyclooxygenase-2 expression in the macula densa. HYPERTENSION, 34 (3). pp. 503-507. ISSN 0194-911X,
Full text not available from this repository.Abstract
The expression of cyclooxygenase 2 (COX-2) in the late thick ascending limb, including the macula densa, is found to be upregulated in an activated renin-angiotensin system. How this upregulation is managed is not yet known. We therefore considered the possibility that the stimulation of COX-2 expression is triggered by the activation of the renin-angiotensin system. For this purpose, we treated male,Sprague-Dawley rats with the angiotensin I-converting enzyme inhibitor ramipril (10 mg/kg per day), the angiotensin II type 1 (AT(1)) receptor blocker losartan (30 mg/kg per day), and the angiotensin II type 2 (AT(2)) receptor blocker PD123319 (6 mg/kg per day) for 4 days. We determined the expression of COX-2 mRNA and protein in the renal cortex. We found that ramipril and the AT(1) receptor blocker losartan increased COX-2 mRNA and COX-2 immunoreactivity in the macula densa approximate to 4-fold, whereas the AT(2) blocker PD123319 showed no effect. A low-salt diet (0.02% wt/wt) stimulated COX-2 expression in the kidney cortex <2-fold. The combination of a low-salt diet with ramipril led to a further increase of COX-2 mRNA and COX-2 immunoreactivity compared with low salt or ramipril alone. These data indicate that endogenous angiotensin II apparently inhibits COX-2 expression in the macula densa via AT(1) receptors and can therefore not account for the stimulation of COX-2 expression associated with an activated renin-angiotensin system. Because macula densa- derived prostaglandins are considered stimulators of renin secretion and renin synthesis, inhibition of macula densa COX-2 by angiotensin II could form a novel indirect negative feedback control of the renin system.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | DIFFERENTIAL REGULATION; PROSTAGLANDIN SYNTHESIS; RAT-KIDNEY; SECRETION; RELEASE; RNA; renin; prostaglandins; angiotensin II |
| Subjects: | 500 Science > 570 Life sciences |
| Divisions: | Biology, Preclinical Medicine > Institut für Physiologie > Prof. Dr. Armin Kurtz |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 21 Dec 2022 15:45 |
| Last Modified: | 21 Dec 2022 15:45 |
| URI: | https://pred.uni-regensburg.de/id/eprint/49024 |
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