title: Pharmacokinetics of tetrodotoxin in puffer fish Takifugu rubripes by a single administration technique.
abstract: Marine puffer fish accumulates tetrodotoxin (TTX) in the liver and ovary. In this study, we examined the pharmacokinetics of TTX in Takifugu rubripes by a single administration under general anesthesia at 20 degrees C for 300 min. The blood concentration-time profile showed multiple distinct phases after injection into hepatic portal vein. The area under the blood concentration-time curve (AUC) increased linearly at the dosage of 0.25-0.75 mg TTX/kg body weight, and the total body clearance was 2.06+/-0.17 mL/min/kg body weight. The AUCs following administration into the hepatic portal vein and hepatic vein were closely similar (147+/-33 versus 141+/-1 ng.min/microL), indicating negligible hepatic first-pass effect. Comparison of the AUCs following an administration to the hepatic vein and gastrointestinal tract (0.25 mg TTX/kg body weight) elucidated the bioavailability of TTX to be 62%. There was no significant increase in the AUCs following direct injection into the gastrointestinal tract (0.50 versus 1.0 mg TTX/kg body weight). At the dosage of 0.25 mg TTX/kg body weight into the hepatic vein, hepatic portal vein or gastrointestinal tract, TTX amount in the liver accounted for 84+/-6%, 70+/-9% or 49+/-17% of the total TTX amount applied, respectively. These results demonstrate that TTX is absorbed into the systemic circulation from the gastrointestinal tract by saturable mechanism and finally accumulated in the liver within 300 min.
authors.affiliation: Department of Food Science and Technology, Tokyo University of Marine Science and Technology, Konan 4-5-7, Minato, Tokyo 108-8477, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Matsumoto
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nagashima
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kusuhara
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Ishizaki
authors.forename: Kuniyoshi
authors.initials: K
authors.lastname: Shimakura
authors.forename: Kazuo
authors.initials: K
authors.lastname: Shiomi
mesh_terms: D000818:Animals; D001682:Biological Availability; D001835:Body Weight / Q000187:drug effects* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D005260:Female; D041981:Gastrointestinal Tract / Q000378:metabolism; D006503:Hepatic Veins / Q000378:metabolism; D007275:Injections, Intravenous / Q000379:methods*; D011169:Portal Vein / Q000378:metabolism; D023741:Takifugu / Q000378:metabolism*; D023721:Tetraodontiformes; D013779:Tetrodotoxin / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D013997:Time Factors; D014018:Tissue Distribution
chemical_list: D013779:Tetrodotoxin