PARENT SESSION
MA4 - Biotransformation / Metabolism / Degradation
Chair: Zepp, Richard¹, ¹ U.S. EPA, Athens, GA
8:00 AM to 12:00 PM - Monday, 18 November 2002
Room Ballroom F

(196) Toxicokinetic study of pyrene in tilapias Oreochromis niloticus injected intraperitonealy.

Zapata-Perez, Omar^*,1, Albores, Arnulfo², Gold-Bouchot, Gerardo¹, ¹ CINVESTAV, Merida, Yucatan, Mexico² CINVESTAV, Mexico, D.F., Mexico

ABSTRACT- A toxicokinetic study of pyrene was performed in male tilapias. Fish were weighted and injected i.p. individually with pyrene (20 mg/kg). Tilapias were selected each hour (three individuals) and blood extracted from the caudal vein. Additionally 24, 48, 72, 96 and 120 h after the treatment, three tilapias were sacrificed to collect the bile, the intestine and a part of the liver to assess pyrene and 1-OH pyrene concentrations. The other part of the liver was used to evaluate EROD activity. A two-compartment pharmacokinetic model was fitted to the pyrene blood concentrations, revealing that pyrene was rapidly absorbed in the blood and distributed to different tissues, with a calculated distribution () and elimination () half-lives of 4 hr and 400 hr, respectively. These results are in agreement with the observed pyrene tissue concentrations, where maximum concentrations were found 24 hr after injection in intestine, liver and bile. Afterwards, pyrene decreased gradually, although in intestine high concentrations were detected even after 5 days. On the other hand, the highest transformation of pyrene was observed three days after treatment, where the highest concentrations of the metabolite 1-OH-pyrene in bile were measured. There is a significant association between 1-OH pyrene and EROD activity (Spearman test; r = 0.85), and also with CYP1A protein (r = 0.81), suggesting the participation of CYP1A in the biotransformation of pyrene.

Key words: Toxicokinetic, Pyrene, EROD, Tilapia