Brevetoxin: tissue distribution and effect on cytochrome P450 enzymes in fish.
As part of our investigation of the metabolism of brevetoxin (PbTx) in fish, we initiated a two-part study to determine the toxin's tissue distribution and its ability to induce xenobiotic metabolizing enzymes. In the first study, gulf toadfish (Opsanus beta) were administered 14C-PbTx-3 orally in a fishmeal slurry and sacrificed 72 hr later. Radioactivity was greatest in the hepatobiliary system (40% of body burden), representing the key role this system plays in the detoxification and elimination of brevetoxin. Muscle tissue contained 27%, followed by gastrointestinal tract (25%). To investigate the effects of PbTx on xenobiotic metabolizing enzymes, immature redfish (Scianops ocellatus) were given two doses of brevetoxin (1.5 or 2.5 micrograms/100 g body weight) or cod liver oil in a fishmeal slurry by gavage. The activities of two hepatic P450 enzymes, ethoxyresorufin O-deethylase (EROD) and pentoxyresorufin O-depentylase (PROD), as well as the cytosolic enzyme, glutathione S-transferase (GST), were measured. At the higher dose, PbTx significantly increased EROD activity. These results suggest that brevetoxin is capable of inducing an important xenobiotic metabolizing enzyme (EROD).
Washburn
B S
BS
Division of Marine Biology & Fisheries, Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, FL 33149.
Baden
D G
DG
Gassman
N J
NJ
Walsh
P J
PJ
D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000187:drug effects*; D005399:Fishes / Q000378:metabolism*; D008099:Liver / Q000201:enzymology; D008387:Marine Toxins / Q000493:pharmacokinetics* / Q000633:toxicity*; D035964:Oxocins; D014018:Tissue Distribution; D000095702:Polyether Toxins
D003577:Cytochrome P-450 Enzyme System; D008387:Marine Toxins; D035964:Oxocins; C053342:brevetoxin; D000095702:Polyether Toxins