Kinetics of hepatic phase I and II biotransformation reactions in eight finfish species

Abstract

Hepatic microsomes and cytosols of channel catfish (Ictalurus punctatus), rainbow trout (Oncorhynchus mykiss), Atlantic salmon (Salmo salar), red tilapia (Oreochromis sp.), largemouth bass (Micropterussalmoides), striped bass (Morone saxatilis), hybrid striped bass (M. saxatilis x M. crysops), and bluegill (Lepomis macrochuris) (n=8) were used to study the kinetics of phase I (ECOD, EROD, PROD, BROD) and phase II (UDP-glucuronosyltransferase (UDPGT)-, sulfotransferase (ST)- and glutathione-s-transferase (GST)-mediated) reactions. The best catalytic efficiency for ECOD and GST activities was performed by channel catfish, Atlantic salmon, rainbow trout and tilapia. The highest EROD catalytic efficiency was for Atlantic salmon. None of the species had either PROD or BROD activities. Rainbow trout had very similar UDPGT catalytic efficiency to tilapia, channel catfish, Atlantic salmon, largemouth bass and bluegill. Sulfotransferase conjugation had no significant differences among the species. In summary, tilapia, channel catfish, Atlantic salmon and rainbow trout had the best biotransforming capabilities; striped bass, hybrid striped bass and bluegill were low metabolizers and largemouth bass shared some capabilities with both groups.

Seasonal Variations of the Activity of Antioxidant Defense Enzymes in the Red Mullet (Mullus barbatus l.) from the Adriatic Sea

“…Phase I and phase II biotransformation reactions are of great importance in the understanding of metabolism of endogenous molecules and transformation of xenobiotics and drugs in fish and other species [12]. The main enzymes that detoxify ROS in all organisms are functionally divided into antioxidant defense enzyme activities (superoxide dismutase-SOD, catalase-CAT, glutathione peroxidase-GSH-Px and glutathione reductase-GR) and biotransformation phase II components (for instance, glutathione-S-transferase-GST and reduced/oxidized glutathione) [8].…”

Biomarkers study in rainbow trout exposed to industrially contaminated groundwater

“…16 The induction of GST activity as for CYP450 is regulated, in part by the Ah receptor. 25 Indeed, an increase in hepatic GST activity has been reported in several studies after fish exposure to PAHs, PCBs and certain VOCs. 17,45,46 Various substrates involved in GST activity are recognized by the binding site of hydrophobic substrates.…”

“…Glutathione S-transferase is an important phase II enzyme that catalyses the conjugation of electrophilic compounds to GSH, 25 GST reacts with a wide spectrum of environmental pollutants. 26,27 It has been reported that the enzyme GST react differently to a variety of compounds.…”

Effects of pharmaceuticals present in aquatic environment on Phase I metabolism in fish

“…Regulation occurs by various mechanisms including inhibition and induction. Additionally, protein and gene expressions vary between fishspecies and sexes and are affected by diet (Celander et al, 1989;Christen and Fent, 2014;Crago and Klaper, 2011;Gonzalez et al, 2009). …”