Distribution and function of tetrodotoxin-binding proteins in the pufferfish Takifugu rubripes -elucidation from a viewpoint of sexual maturation

利用无毒养殖河豚进行的各种河豚毒素（TTX）给药实验，以及对几种野生河豚鱼和虎鱼（Yongeichthys criniger）体内TTX分布的调查表明，TTX在体内的动力学变化取决于这些携带TTX的鱼类的皮肤/肝脏发育（由于生长）和卵巢发育/成熟（由于性成熟）。此外，通过对几种河豚ttx结合蛋白（PSTBP）同源基因的搜索发现，红鳍东鲀具有3个候选基因，其中2个在血浆中以蛋白形式存在，另外3种毒性河豚也具有2结构域型候选基因，其糖链结合位点的差异可能与毒素蓄积能力有关。

Various tetrodotoxin (TTX) administration experiments using non-toxic cultured pufferfish, and investigations on internal TTX distribution of several wild pufferfish species and the goby Yongeichthys criniger demonstrated that TTX kinetics inside the body changes depending on the skin/liver development due to growth, and ovary development/maturation due to sexual maturation in these TTX-bearing fish. Moreover, searches for homologous genes of the TTX-binding protein (PSTBP) on several pufferfish species indicated that Takifugu rubripes possesses 3 candidate genes, 2 of which actually exist as proteins in the blood plasma, and that the other 3 toxic species also have 2-domain type candidate genes, and the difference in their sugar chain binding sites may be related to the toxin accumulation ability.