Expression dynamics of the genes for the hypothalamo-pituitary-gonadal axis in tiger puffer (Takifugu rubripes) at different reproductive stages

•The gene expression patterns were examined for hypothalamic neuropeptides and pituitary hormones in wild tiger puffer.•The expression of the genes for three GnRHs, GnIH, GnIH-R, FSHβ and LHβ were extensively activated in the mature fish.•The expression levels of the GnRH/GnIH/GTH system were drastically decreased in the post-ovulatory females.