[Purification of the brain hormone of Nereis diversicolor and Perinereis cultrifera (Annelida:Polichaeta) by high-pressure liquid chromatography (HPLC)].

Five thousand brains inhibiting gametogenesis in Nereis diversicolor and Perinereis cultrifera were extracted with cold methanol, giving a micromolecular fraction containing the whole of the inhibitory activity of the brains. This micromolecular fraction, fractionated (i) on Sephadex G 25 fine and (ii) on Sephadex G 25 superfine, gave an inhibitory peak (P 5) in organ culture. Fraction P 5, purified by high-pressure liquid chromatography, showed an area with the same biological inhibitory activity as the blank brains.