Relationships among mammalian gonadotropin-releasing hormone, prostaglandins, and sex steroids in the brain of the crested newt, Triturus carnifex

The present study was carried out to evaluate the in vitro brain release of prostaglandin F_2α (PGF_2α), prostaglandin E₂ (PGE₂), androgens, and 17β-estradiol in male and female crested newt, Triturus carnifex, during three different periods of the annual sexual cycle; in addition, the effects of mammalian gonadotropin-releasing hormone (mGnRH), PGF_2α, and PGE₂ on prostaglandins and steroids release by the brain were evaluated during the same periods. In brain incubations of both sexes, PGF_2α and estradiol were higher during postreproduction, while PGE₂ and androgens were higher during reproduction. In both sexes, mGnRH increased PGF_2α and estradiol during postreproduction, and PGE₂ during reproduction; PGF_2α increased estradiol secretion during postreproduction. Only in the male, did both mGnRH and PGE₂ increase androgens during reproduction. It could be suggested that in Triturus carnifex, the regulation of the reproductive activity in the central nervous system (CNS) depends on the relationships among mGnRH, prostaglandins and steroids. In particular, PGF_2α and PGE₂ seem to play different roles in the CNS of the newt: PGF_2α is involved in the postreproductive processes, through estradiol secretion, while PGE₂ in the reproductive ones (through androgens secretion?).