Inhibition of renin secretion from rat renal cortical slices by (R)-12-HETE

The arachidonic acid metabolite 12-hydroxyeicosatetraenoic acid (12-HETE) inhibits renin secretion both in vivo and in vitro, but the enzymatic origin of the 12-HETE responsible for renin inhibition is unknown. These studies examined the effect of the 12-HETE stereoisomers (R)-12-HETE (a product of the cytochrome P-450 monooxygenase enzyme system) and (S)-12-HETE (a product of the lipoxygenase enzyme system) on basal and stimulated renin secretion from superficial cortical slices in the rat. First, rat cortex was shown to produce 12-HETE; chiral-phase high-performance liquid chromatography revealed that cortex produced 81% (S)-12-HETE and 19% (R)-12-HETE. (R)-12-HETE reduced basal renin release by 28 ± 4% to 49 ± 5% at concentrations of 10^-9 to 10^-7 M (P < 0.05 to 0.01). (S)-12-HETE did not significantly affect renin release. (R)-12-HETE also blunted isoproterenol-stimulated renin secretion (P < 0.05) at a concentration of 10^-6 M. 20-HETE, another cytochrome P-450 product, did not exert a significant effect on renin release. In summary, both (R)-12-HETE and (S)-12-HETE are synthesized by renal cortical tissue. Only (R)-12-HETE directly inhibits in vitro renin release. These findings suggest that the renal cytochrome P-450 enzyme system is capable of directly influencing local renin secretion.