Suppression of leptin-AI/AII transcripts by insulin in goldfish liver: a fish specific response of leptin under food deprivation.

•The goldfish hepatic insulin, glucagon, leptin-AI and -AII mRNA during fasting and refeeding were examined.•Insulin suppresses leptin-AI and -AII mRNA in in vivo and in vitro experiments.•Insulin inhibits leptin expression via insulin receptor coupled with MAPK-dependent cascades.•Insulin reduces the glucagon-induced leptin expression.•The fish-specifically high leptin level under food deprivation may be mediated by insulin and glucagon.