Arachidonic acid stimulates steroidogenesis in goldfish preovulatory ovarian follicles.

The possibility that arachidonic acid (AA) plays a role in the regulation of steroidogenesis in goldfish was investigated using preovulatory ovarian follicles incubated in vitro. AA was shown to act in a time- and dose-dependent manner to stimulate testosterone production. AA in the range of 10(-5) to 10(-4) M increased testosterone production within 2 hr and had a maximal effect by 9 hr. The magnitude of the testosterone response to AA was similar to that observed when ovarian follicles were incubated with human chorionic gonadotropin (hCG). Ovarian follicles incubated with AA and either hCG or forskolin (adenylate cyclase activator) produced more testosterone than follicles incubated with either of these compounds alone. The actions of AA on testosterone production were completely blocked by cyclooxygenase inhibitors (indomethacin or ibuprofen) and were reduced by 50% by the lipoxygenase inhibitor nordihydroguaiaretic acid. Phospholipase C was far more effective than phospholipase A2 in the stimulation of testosterone production. Taken together, these results suggest that AA formed subsequent to the action of phospholipase C on membrane phospholipids has a role in the regulation of steroidogenesis in preovulatory goldfish ovarian follicles.