Effect of pyrene on hepatic cytochrome P450 1A (CYP1A) expression in nile tilapia (Oreochromis niloticus)

• Published in: Archives of environmental contamination and toxicology 2002-05, Vol.42 (4), p.477-485
• Main Authors: ZAPATA-PEREZ, O, GOLD-BOUCHOT, G, ORTEGA, A, LOPEZ, T, ALBORES, A
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animal, plant and microbial ecology; Animals; Applied ecology; Biological and medical sciences; Biotransformation; Body weight; Brackish; Cichlids - metabolism; Cytochrome; Cytochrome P-450 CYP1A1 - biosynthesis; Cytochrome P-450 CYP1A1 - genetics; DNA, Complementary - biosynthesis; Dose-Response Relationship, Drug; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on protozoa and invertebrates; Effects of pollution and side effects of pesticides on vertebrates; Enzyme Induction; Fish; Freshwater; Fundamental and applied biological sciences. Psychology; Gene expression; Gene Expression Regulation, Enzymologic - drug effects; Injection; Injections, Intraperitoneal; Mammalia; Microsomes, Liver - drug effects; Microsomes, Liver - enzymology; Molecular Sequence Data; Oreochromis niloticus; Ponds; Pyrene; Pyrenes - toxicity; Sequence Alignment; Tilapia; Tropical fish; Water Pollutants, Chemical - toxicity
• ISSN: 0090-4341; 1432-0703
• DOI: 10.1007/s00244-001-0018-1

The effect of pyrene on the regulation of the gene expression of cytochrome P4501A ( CYP1A) was studied in tilapia (Oreochromis niloticus), a tropical fish of great ecological and economical importance. To evaluate CYP1A mRNA, tilapia CYP1A cDNA was cloned, sequenced, and compared with those CYP1A reported sequences in the GeneBank DNA database. The top seven matches corresponded to CYP1A from other teleosts. Hepatic CYP1A mRNA levels showed a significant increase at day 1 after pyrene injection (20 mg kg(-1) body weight [BW]), and this CYP1A mRNA levels did not return to basal levels for up to 5 days. The immunoblot analysis of CYP1A protein levels using polyclonal rabbit-anti-trout antibodies in the liver of pyrene-treated (20 mg kg(-1) BW) tilapias showed a 1.9-fold increase at day 3 after injection. Ethoxyresorufin- O-deethylase (EROD) activity increased 18-fold with respect to control fish at day 3 after injection. CYP1A protein and EROD activity remained increased for 5 days after a single pyrene IP administration. Similarly, the highest concentration of 1-hydroxypyrene (1-OH pyrene) in bile was observed in fish sacrificed at day 3 after injection. EROD activity and 1-OH pyrene concentration showed a statistically significant correlation (r = 0.85) according to the Spearman test, suggesting the participation of this cytochrome in the biotransformation of pyrene.