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Renal 20-HETE inhibition attenuates changes in renal hemodynamics induced by L-NAME treatment in pregnant rats
- Source :
- The American Journal of Physiology. Nov, 2005, Vol. 289 Issue 5, pF1116, 7 p.
- Publication Year :
- 2005
-
Abstract
- We previously reported that inhibition of nitric oxide (NO) synthesis by N-nitro-L-arginine methyl ester (L-NAME) during late pregnancy leads to increased production of renal vascular 20-hydroxyeicosatetraenoic acid (20-HETE), a cytochrome P-450 (CYP) 4A-derived vasoconstrictor, in pregnant rats. However, the effect of upregulation of vascular 20-HETE production on renal function after NO inhibition is not known. To test the hypothesis that increased gestational vascular 20-HETE synthesis after NO inhibition is involved in mediating blood pressure and renal functional changes, we first determined the I[C.sub.50] value of the effect of nitroprusside (SNP), a NO donor, on renal 20-HETE production in cortical microsomes. We then divided pregnant rats and age-matched virgin rats into a vehicle control group, an L-NAME treatment group (0.25 mg/ml in drinking water), and a group treated with L-NAME plus N-methylsulfonyl- 12,12-dibromododec-11-enamide (DDMS; CYP4A-selective inhibitor, l0 mg x [kg.sup.-1] x [day.sup.-1] iv). After 4 days of treatment, we measured blood pressure, renal blood flow (RBF), renal vascular resistance (RVR), and glomerular filtration rate (GFR) in each group. The addition of SNP (I[C.sub.50] = 22 [micro]M) decreased renal cortical 20-HETE production. In pregnant rats, L-NAME treatment led to significantly higher mean arterial pressure (MAP) and RVR, and lower RBF and GFR. Combined treatment with DDMS and L-NAME significantly attenuated the increases in MAP and RVR and the decrease in GFR, but not the reduction in RBF induced by L-NAME treatment. L-NAME and L-NAME plus DDMS had no significant impact on renal hemodynamics in virgin rats. In addition, chronic treatment with DDMS selectively inhibited cortical 20-HETE production without a significant effect on CYP4A expression in L-NAME-treated pregnant rats. In conclusion, NO effectively inhibits renal cortical microsomal 20-HETE production in female rats. In pregnant rats, the augmentation of renal 20-HETE production after NO inhibition is associated with increased MAP and RVR, whereas decreased GFR is negated by treatment of a selective and competitive CYP4A inhibitor. These results demonstrate that the interaction between renal 20-HETE and NO is important in the regulation of renal function and blood pressure in pregnant rats. pregnancy; cytochrome P-450; arachidonic acid; eicosanoid; kidney; nitric oxide; hypertension
Details
- Language :
- English
- ISSN :
- 00029513
- Volume :
- 289
- Issue :
- 5
- Database :
- Gale General OneFile
- Journal :
- The American Journal of Physiology
- Publication Type :
- Academic Journal
- Accession number :
- edsgcl.139430162