Difference in the localization of tetrodotoxin between the female and male pufferfish Takifugu niphobles, during spawning

► Tissue localization and amounts of TTX in the pufferfish Takifugu niphobles were different between the two sexes. ► Gonadal TTX amounts were significantly lower in the males and at non-toxic levels. ► Toxin amounts in the skin and liver were higher in males. ► TTX appears to be transported from basal skin cells to epithelium.