title: Acute Toxicities of the Saxitoxin Congeners Gonyautoxin 5, Gonyautoxin 6, Decarbamoyl Gonyautoxin 2&3, Decarbamoyl Neosaxitoxin, C-1&2 and C-3&4 to Mice by Various Routes of Administration.
abstract: Paralytic shellfish poisoning results from consumption of seafood naturally contaminated by saxitoxin and its congeners, the paralytic shellfish toxins (PSTs). The levels of such toxins are regulated internationally, and maximum permitted concentrations in seafood have been established in many countries. A mouse bioassay is an approved method for estimating the levels of PSTs in seafood, but this is now being superseded in many countries by instrumental methods of analysis. Such analyses provide data on the levels of many PSTs in seafood, but for risk assessment, knowledge of the relative toxicities of the congeners is required. These are expressed as "Toxicity Equivalence Factors" (TEFs). At present, TEFs are largely based on relative specific activities following intraperitoneal injection in a mouse bioassay rather than on acute toxicity determinations. A more relevant parameter for comparison would be median lethal doses via oral administration, since this is the route through which humans are exposed to PSTs. In the present study, the median lethal doses of gonyautoxin 5, gonyautoxin 6, decarbamoyl neosaxitoxin and of equilibrium mixtures of decarbamoyl gonyautoxins 2&amp;3, C1&amp;2 and C3&amp;4 by oral administration to mice have been determined and compared with toxicities via intraperitoneal injection. The results indicate that the TEFs of several of these substances require revision in order to more accurately reflect the risk these toxins present to human health.
authors.affiliation: Cawthron Institute, Private Bag 2, Nelson 7042, New Zealand. andy.selwood@cawthron.org.nz.
authors.forename: Andrew I
authors.initials: AI
authors.lastname: Selwood
authors.affiliation: Cawthron Institute, Private Bag 2, Nelson 7042, New Zealand. craig.waugh@cawthron.org.nz.
authors.forename: Craig
authors.initials: C
authors.lastname: Waugh
authors.affiliation: Cawthron Institute, Private Bag 2, Nelson 7042, New Zealand. tim.harwood@cawthron.org.nz.
authors.forename: David T
authors.initials: DT
authors.lastname: Harwood
authors.affiliation: Cawthron Institute, Private Bag 2, Nelson 7042, New Zealand. lesley.rhodes@cawthron.org.nz.
authors.forename: Lesley L
authors.initials: LL
authors.lastname: Rhodes
authors.affiliation: Ministry for Primary Industries, P.O. Box 2526, Wellington 6140, New Zealand. john.reeve@mpi.govt.nz.
authors.forename: John
authors.initials: J
authors.lastname: Reeve
authors.affiliation: Ministry for Primary Industries, P.O. Box 2526, Wellington 6140, New Zealand. jim.sim@mpi.govt.nz.
authors.forename: Jim
authors.initials: J
authors.lastname: Sim
authors.affiliation: AgResearch Limited, Ruakura Research Centre, Private Bag 3123, Hamilton 3240, New Zealand. rex.munday@agresearch.co.nz.
authors.forename: Rex
authors.initials: R
authors.lastname: Munday
mesh_terms: D000284:Administration, Oral; D000818:Animals; D005260:Female; D007274:Injections, Intraperitoneal; D007928:Lethal Dose 50; D051379:Mice; D019055:No-Observed-Adverse-Effect Level; D012530:Saxitoxin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000633:toxicity
chemical_list: D012530:Saxitoxin; C034902:neosaxitoxin; C013007:gonyautoxins
keywords: 2; 4; C1&amp; C3&amp; acute toxicity; decarbamoyl gonyautoxins; decarbamoyl neosaxitoxin; gonyautoxins; oral exposure; paralytic shellfish toxins; toxicity equivalence factors