Response of superfused goldfish pituitary fragments to mammalian and salmon gonadotropin-releasing hormones.

Salmon and mammalian gonadotropin-releasing hormones (sGnRH, mGnRH) were tested for their ability to stimulate in vitro gonadotropin (GtH) release from superfused goldfish pituitary fragments. A two minute exposure to either peptide was sufficient to stimulate a dose-dependent increase in GtH release which reached maximum levels in 15 minutes and returned to baseline within one hour. Both peptides were approximately equipotent in stimulating GtH release, as was a superactive analog of mGnRH. These results demonstrate that sGnRH is capable of directly stimulating GtH release from teleost pituitary tissue, and that structural differences between the three peptides tested do not result in significant differences in in vitro bioactivity.