11-ketotestosterone induces male-type sexual behavior and gonadotropin secretion in gynogenetic crucian carp, Carassius auratus langsdorfii

Abstract

To determine if a gynogenetic teleost might have a sexually bipotential brain, we tested whether implantation of 11-ketotestosterone (KT) induces male-type sexual behavior and gonadotropin (GTH) secretion in adult gynogenetic crucian carp, "ginbuna," Carassius auratus langsdorfii. KT-implanted female ginbuna were tested for male spawning behavior by pairing them with a stimulus female in which sexual receptivity and attractivity were induced by prostaglandin F(2alpha) (PG) injection. When KT-implanted female ginbuna were paired with a PG-injected stimulus female ginbuna, all the KT-implanted fish tested showed male spawning behavior in response to the PG-injected females. KT-implanted fish also showed female spawning behavior when they were injected with PG. When the KT-implanted female ginbuna were exposed to waterborne 17alpha,20beta-dihydroxy-4-pregnen-3-one (a female sex pheromone that stimulates male-typical GTH secretion in goldfish), all the KT-implanted fish showed an elevation of plasma GTH levels in response to the pheromone. These results demonstrate that gynogenetically evolved ginbuna, like goldfish, is sexually plastic and can be behaviorally and endocrinologically masculinized by androgen treatment without behavioral defeminization. These results support our hypothesis that adult teleosts retain a sexually bipotential brain regardless of reproductive strategy, i.e., hermaphroditism, gonochorism, or gynogenesis.