Department of Ecophysiology and Aquaculture, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, 12587, Berlin, Germany
Faculty of Life Sciences, Thaer-Institute of Agricultural and Horticultural Sciences, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115, Berlin, Germany
Two types of gonadotropin-releasing hormones (GnRH) were identified as gnrh1 and gnrh2 in pikeperch Sander lucioperca. 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.