Insights into kisspeptin- and leptin-signalling on GnRH mRNA expression in hypothalamic organ cultures of immature pikeperch Sander lucioperca

Abstract

Two types of gonadotropin-releasing hormones (GnRH) were identified as gnrh1 and gnrh2 in pikeperch <em>Sander lucioperca</em>. The administration of rodent leptin on hypothalamic organ cultures of immature pikeperch resulted in significantly elevated levels of gnrh2, but not in gnrh1 mRNA, whereas kisspeptin-10 administration did not affect gnrh1 or gnrh2 expression. These results represent preliminary insights into leptin-GnRH-signaling on a hypothalamic level in fish, potentially coupling fat metabolism and the activation of the reproductive axis during puberty. Mammalian leptin and kisspeptin-10, however, failed to initiate a consistent response in pikeperch and their use cannot be recommended.