Abstract
The present study describes the presence and localization of three forms of GnRH mRNAs in the gonadal tissues of the marine hermaphrodite, Sparus aurata, at several characteristic stages of the reproductive cycle. The relative expression profiles of seabream (sb)GnRH, salmon (s)GnRH and chicken (c)GnRH-II within the ovarian and testicular tissues were found to vary according to the stage of reproductive activity.