Antioxidant defence enzyme activities in hepatopancreas, gills and muscle of Spiny cheek crayfish (Orconectes limosus) from the River Danube ☆ Slavica S. Borković a , Sladjan Z. Pavlović a , Tijana B. Kovačević a , AndrašŠ. Štajn b , Vojislav M. Petrović a , Zorica S. Saičić a, ⁎ a Department of Physiology, Institute for Biological Research “Siniša Stanković”, University of Belgrade, Bulevar despota Stefana 142, 11060 Belgrade, Serbia b Institute of Biology and Ecology, Faculty of Sciences, University of Kragujevac, Radoja Domanovića 12, 34000 Kragujevac, Serbia Received 23 May 2007; received in revised form 20 August 2007; accepted 22 August 2007 Available online 28 August 2007 Abstract The aim of our study was to determine the activity of antioxidant defence (AD) enzymes: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR) and the phase II biotransformation enzyme glutathione-S-transferase (GST) in the hepatopancreas, the gills and muscle of Spiny cheek crayfish (Orconectes limosus) from the River Danube and to compare tissue specificities of investigated enzymes. Our results indicated that both specific and total SOD activities in the hepatopancreas were lower compared to the gills and muscle. Total SOD activity in the gills was lower with respect to that in muscle. CAT and GSH-Px (both specific and total) activities were higher in the hepatopancreas compared to those in the gills and muscle. In the gills the specific and total GR activities were higher than in the hepatopancreas and muscle. The specific and total GST activities were higher in the hepatopancreas compared with the gills and muscle. Our study represents the first comprehensive report of AD enzymes in tissues of O. limosus caught in the River Danube. The noted tissue distributions of the investigated AD enzyme activities most likely reflected different metabolic activities and different responses to environmental conditions in the examined tissues. © 2007 Elsevier Inc. All rights reserved. Keywords: Antioxidant defence enzymes; Biomonitoring; Oxidative stress; River Danube; Spiny cheek crayfish 1. Introduction Aquatic life is constantly exposed to chemical contamination by an increasing variety of anthropogenic activities that can induce many different mechanisms of toxicity, each contribut- ing to varying degrees to the final overall deleterious effect (Correia et al., 2003). The main antioxidant defence (AD) enzymes in all organisms are superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR) and the phase II biotransformation enzyme glutathione-S-transferase (GST). These enzymes can be induced by reactive oxygen species (ROS) and therefore they may represent indicators of oxidative stress (Pavlović et al., 2004). The induction of AD enzymes may provide sensitive early- warning signals of incipient oxidative stress conditions. AD enzymes play a crucial role in maintaining cellular homeostasis. AD enzymes, such as SOD, CAT, GSH-Px and GR act by detoxifying the ROS generated. Furthermore, the phase II detoxifying enzyme GST produces a glutathione (GSH) conjugate that appears to be the first step in the detoxification of many toxins (Sureda et al., 2006). The enzymes mentioned above have been proposed as biomarkers of contaminant- mediated oxidative stress in a variety of marine and freshwater organisms and their induction reflects a specific response to pollutants (Borković et al., 2005; Cossu et al., 1997). Previous reports have considered GSH-dependent enzymes and other AD enzymes as markers for oxidative stress in fish (Hasspieler et al., 1994; Pavlović et al., 2004). AD enzymes can be induced by various environmental pro-oxidant conditions (those that induce ROS generation, for example exposure to various types of Available online at www.sciencedirect.com Comparative Biochemistry and Physiology, Part C 147 (2008) 122 – 128 www.elsevier.com/locate/cbpc ☆ This article is dedicated to the memory of the Academician Prof. Dr Vojislav M. Petrović. ⁎ Corresponding author. Tel.: +381 11 2078 325; fax: +381 11 2761 433. E-mail address: zorica.saicic@ibiss.bg.ac.yu (Z.S. Saičić). 1532-0456/$ - see front matter © 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.cbpc.2007.08.006