Secretory glands of tetrodotoxin in the skin of the Japanese newt Cynops pyrrhogaster

Intra-tissue distribution of tetrodotoxin (TTX) in the skin of larva, juven ile, and adult Japanese newt Cynops pyrrhogaster was investigated by means of a monoclonal antibody-based immunoenzymatic technique. In the investigat ion, TTX was localized at immature glands in juvenile, and at the granular cells composing of granular and mixed glands in adult specimens under a lig ht microscope. No specific stain was recognized in larval section. A duct l ike structure extending from the granular gland towards super epithelial la yer was visualized in the toluidine blue treated skin section of adult newt . When stimuli by wiping with gauze ('handling stimulus') were given, C. py rrhogaster was found to secrete an applicable amount of TTX and 6-epiTTX fr om the skin, suggesting that the newt has a granular gland of TTX to secret e it towards the body surface possibly as a biological defensive agent. (C) 2001 Elsevier Science Ltd. All rights reserved.