Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P41181 (collecting duct)
 5,183 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

High dietary potassium stimulates the renal expression of cytochrome P450 (CYP) epoxygenase 2C23, which metabolizes arachidonic acid (AA). Because the AA metabolite 11,12-epoxyeicosatrienoic acid (11,12-EET) can inhibit the epithelial sodium channel (ENaC) in the cortical collecting duct, we tested whether dietary potassium modulates ENaC function. High dietary potassium increased 11,12-EET in the isolated cortical collecting duct, an effect mimicked by inhibiting the angiotensin II type I receptor with valsartan. In patch-clamp experiments, a high potassium intake or treatment with valsartan enhanced AA-induced inhibition of ENaC, an effect mediated by a CYP-epoxygenase-dependent pathway. Moreover, high dietary potassium and valsartan each augmented the inhibitory effect of 11,12-EET on ENaC. Liquid chromatography/mass spectrometry showed that the rate of EET conversion to dihydroxyeicosatrienoic acids (DHET) was lower in renal tissue obtained from rats on a high-potassium diet than from those on a control diet, but this was not a result of altered expression of soluble epoxide hydrolase (sEH). Instead, suppression of sEH activity seemed to be responsible for the 11,12-EET-mediated enhanced inhibition of ENaC in animals on a high-potassium diet. Patch-clamp experiments demonstrated that 11,12-DHET was a weak inhibitor of ENaC compared with 11,12-EET, whereas 8,9- and 14,15-DHET were not. Furthermore, inhibition of sEH enhanced the 11,12-EET-induced inhibition of ENaC similar to high dietary potassium. In conclusion, high dietary potassium enhances the inhibitory effect of AA and 11,12-EET on ENaC by increasing CYP epoxygenase activity and decreasing sEH activity, respectively.
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PMID:High potassium intake enhances the inhibitory effect of 11,12-EET on ENaC. 2059 84