MAMMALIAN GNRH INVOLVEMENT IN PROSTAGLANDIN-F2-ALPHA AND SEX STEROID-HORMONES TESTICULAR RELEASE IN 2 AMPHIBIAN SPECIES - THE ANURAN WATER FROG, RANA-ESCULENTA, AND THE URODELE CRESTED NEWT, TRITURUS-CARNIFEX

The present work was carried out to study the in vitro effects of mammalian gonadotropin-releasing hormone (mGnRH) on Rana esculenta and Triturus carnifex testis production of prostaglandin F2α (PGF2α) and sex steroid hormones during the prereproduction, reproduction, and postreproduction periods. In R. esculenta, testicular PGF2α release was lower during postreproduction, and mGnRH increased PGF2α in prereproduction and reproduction. Androgens were higher during prereproduction, and mGnRH induced an androgens increase in prereproduction and reproduction. In T. carnifex testicular PGF2α release was lower during reprduction, and mGnRH increased PGF2α in prereproduction and reproduction. Androgens were higher in reproduction and lower in postreproduction, and mGnRH induced an androgens increase in reproduction. Estradiol-17β release was higher in postreproduction, and mGnRH induced an estradiol decrease in reproduction and an increase in postreproduction. These results seem to indicate the involvement of PGF2α in the testicular reproductive activity, and a similar mGnRH mechanism of action, both in R. esculenta and in T. carnifex. In addition, taken together with previous studies, they seem to suggest that the relationship found between mGnRH and PGF2α or sex steroids could be widespread in amphibians. © 1992.