TY - JOUR
T1 - 5,6-EET inhibits ion transport in collecting duct by stimulating endogenous prostaglandin synthesis
AU - Sakairi, Yasunori
AU - Jacobson, Harry R.
AU - Noland, Thomas D.
AU - Capdevila, Jorge H.
AU - Falck, John R.
AU - Breyer, Matthew D.
PY - 1995/5
Y1 - 1995/5
N2 - We examined the mechanism by which the cytochrome P-450 metabolite of arachidonate, 5,6-epoxyeicosatrienoic acid (5,6-EET), modulates electrogenic transport in the rabbit cortical collecting duct (CCD). 5,6-EET depolarized transepithelial voltage (VT) in a concentration-dependent manner with a maximal effect at 1 μM. None of the other EET regioisomers (8,9-, 11,12-, or 14,15-EET; all at 1 μM) affected VT. This action was also stereoselective, with 5(S),6(R)-EET producing a 2.5-fold greater effect on VT than 5(R),6(S)-EET (1 μM each). Like basolateral prostaglandin E2 (PGE2), both luminal and basolateral 5,6-EET increased cytosolic Ca2+ concentration ([Ca2+]i) in the rabbit CCD. Pretreatment with cyclooxygenase inhibitors (10 μM ibuprofen or 5 μM indomethacin) completely blocked both the [Ca2+]i increase and the change in VT. Neither 5,6-epoxy-PGE1 nor 5-hydroxy-PGI1, cyclooxygenase metabolites of 5,6-EET, affected VT. However, when added to primary cultures of rabbit CCDs, 5,6-EET stimulated endogenous PGE2 synthesis. We propose that 5,6-EET stimulates endogenous prostaglandin synthesis, which inhibits electrogenic ion transport in the CCD.
AB - We examined the mechanism by which the cytochrome P-450 metabolite of arachidonate, 5,6-epoxyeicosatrienoic acid (5,6-EET), modulates electrogenic transport in the rabbit cortical collecting duct (CCD). 5,6-EET depolarized transepithelial voltage (VT) in a concentration-dependent manner with a maximal effect at 1 μM. None of the other EET regioisomers (8,9-, 11,12-, or 14,15-EET; all at 1 μM) affected VT. This action was also stereoselective, with 5(S),6(R)-EET producing a 2.5-fold greater effect on VT than 5(R),6(S)-EET (1 μM each). Like basolateral prostaglandin E2 (PGE2), both luminal and basolateral 5,6-EET increased cytosolic Ca2+ concentration ([Ca2+]i) in the rabbit CCD. Pretreatment with cyclooxygenase inhibitors (10 μM ibuprofen or 5 μM indomethacin) completely blocked both the [Ca2+]i increase and the change in VT. Neither 5,6-epoxy-PGE1 nor 5-hydroxy-PGI1, cyclooxygenase metabolites of 5,6-EET, affected VT. However, when added to primary cultures of rabbit CCDs, 5,6-EET stimulated endogenous PGE2 synthesis. We propose that 5,6-EET stimulates endogenous prostaglandin synthesis, which inhibits electrogenic ion transport in the CCD.
KW - 5,6-epoxyeicosatrienoic acid
KW - Arachidonate
KW - Cytochrome P-450
KW - Kidney
KW - Sodium
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M3 - Article
C2 - 7771521
AN - SCOPUS:0029059860
SN - 0363-6127
VL - 268
SP - F931-F939
JO - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
JF - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
IS - 5 37-5
ER -