Prostaglandin E2-9-ketoreductase and prostaglandin F2 alpha activate brain aromatase to induce courtship in the male crested newt, Triturus carnifex.

Testosterone, 17 beta-estradiol, prostaglandin E2 (PGE2), and prostaglandin F2 alpha (PGF2alpha) were monitored in plasma and in vitro brain incubations during the main phases of male Triturus carnifex courtship. Plasma and in vitro results were similar: testosterone was highest in inactive males, while 17 beta-estradiol and PGF2 alpha were highest and PGE2 lowest during approach. PGF2 alpha in vitro treatments decreased testosterone and increased 17 beta-estradiol, while 9-ketoreductase inhibitor in vitro treatments increased testosterone and decreased estradiol. In addition, in vitro aromatase and PGE2-9-ketoreductase activities were highest during approach. PGF2 alpha in vitro treatments increased aromatase, while 9-ketoreductase inhibitor decreased aromatase. These results suggest that 9-ketoreductase and PGF2 alpha enhance aromatase activity to trigger male Triturus carnifex courtship.