Biotransformation enzymes of xenobiotics (ethoxyresorufin-O-deethylase,
cytochrome P4501A1 content and glutathione-S-transferase) were investigated
in the liver of Persian Sturgeon (Acipenser persicus) after a 96-hour
exposure to polycyclic aromatic hydrocarbons (PAHs), premutagenic
benzo[a]pyrene (BaP) and beta-naphthoflavone (BNF). The fish were injected 10
mg/kg wet-body weight in corn oil for 96 hours every days.
Ethoxyresorufin-O-deethylase activity (EROD) and glutathione s-transferase
activity (GST) were measured in the fish liver. Cytochrome P4501A1 (CYP1A1)
content was estimated by indirect enzyme-linked immunosorbent assay (ELISA).
The response appeared as early as 12 hours post exposure. A time-dependent
response was observed in the EROD activity, being significantly higher at 48
hours post exposure to 10 mg/kg of BaP. The greatest induction occurred in
the fish treated with 10 mg/kg BaP, in which a 32.1- fold increase in EROD
activity was observed. Results showed that EROD activity in A. persicus is
significantly increased by BaP and BNF treatments. Both chemicals showed
higher values of EROD activity compared to the liver CYP1A content. There was
a rise in glutathione-S-transferase activity in fish exposed to BNF, but no
increase was observed in fish treated with BaP. The results showed that
hepatic CYP1A expression in terms of induction of EROD activity might be
suited as a biomarker of organic contamination in aquatic environments and
led to lower sensitivity of the second phase in the detoxification enzyme
