Arachidonic acid metabolites as intratesticular factors controlling androgen production.

The effect of inhibitors and products of arachidonic acid metabolism on rat testicular steroidogenesis has been investigated. In the presence of indomethacin (inhibitor of cyclooxygenase) and nordihydroguaiaretic acid (NDGA) (inhibitor of lipoxygenase), the activity of 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) and 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) were both inhibited. The LH-stimulated increase in secretion of testosterone and progesterone was also inhibited by indomethacin and NDGA. On the other hand, vitamin E (antioxidant and inhibitor of lipoxygenase), stimulated the activity of both 3 beta-HSD and 17 beta-HSD and enhanced LH-stimulated androgen production. The metabolites of lipoxygenase (15-HPETE, 15-HETE, 5-HPETE and 5-HETE) and cyclooxygenase (PGF2 alpha) pathways stimulated 3 beta-HSD and 17 beta-HSD activity and enhanced the secretion of progesterone and testosterone. It is concluded that arachidonic acid metabolites are intratesticular factors which can regulate LH-stimulated testicular steroidogenesis.