122 Effect of bisphenol a on oxidative metabolism in f ish EFFECT OF BI SPH ENOL A ON OXI DATI VE M ETABOLI SM I N A FRESH WATER TELEOST, ANABAS TESTUDI NEUS (BLOCH) Gireesh Kumar, K.* and Francis Sunny Dept. of Zoology, University College, Thiruvananthapuram, Kerala. Corresponding author: gireeshkadakkal@gmail.com Abstract: In this present study, an attempt was made to understand the role of bisphenol A (BPA) on the activities of hepatic mitochondrial Na + K + ATPase, Ca 2+ ATPase, malate dehydrogenase [MDH] and isocitrate dehydrogenase [ICDH] in a freshwater fish, Anabas testudineus. The results revealed that sub lethal exposure of BPA at different concentrations (2.5, 5.0 and 7.5 mg/l) for a period of 15, 30 and 45 days signif icantly influenced the activities of the mitochondrial enzymes in A. testudineus. Exposure of 2.5, 5.0 and 7.5 mg/ lBPA significantly decreased the activity of hepatic mitochondrial Na + K + ATPase and Ca 2+ ATPase for 15, 30 and 45 days.Since the activity of ATPases was decreased, it is proposed that BPA influences mitochondrial membrane potential, a key factor responsible for mitochondrial metabolism.Exposure to BPA(2.5, 5.0 and 7.5 mg/l) significantly decreased the activity of ICDH for 15, 30 and 45 days.The MDH level significantly decreased following 2.5 and 5.0mg/l BPAexposure for a period of 15, 30 and 45 days. While the MDH activity decreased after 7.5mg/ l BPA exposure for15 and 30 days, but in 45 days of exposure, the MDH activity was restored. The electropherograms revealed the absence of some proteins and also the appearance of some new proteins having appropriate molecular weights when compared to control. Hence based on the results of present study, it is concluded that BPA may exert its influence on oxidative metabolism in A. testudineus probably by disrupting the action of some hormones, which control mitochondrial metabolism. Key words: Bisphenol A, Na + K + ATPase, Ca 2+ ATPase, Isocitrate dehydrogenase, Malate dehydrogenase, Oxidative metabolism. INTRODUCTION In recent years, a growing body of scientific research indicates that chemicals in the environment may interfere with the normal function of the endocrine system of animals. These compounds may be man-made such as industrial chemicals, crop protection chemicals, synthetic hormones or natural chemicals like phytoestrogens (Arukwe, 2001; Swan et al ., 2003). BisphenolA (BPA) is an endocrine disruptor and is a compound widely used in the production of polycarbonate and other plastics with an annual production exceeding 420000 tons (Alexander et al., 1988). Bisphenol A is present in certain food contact materials because it is used in the production of polycarbonate and epoxy-phenolic resins. According to Pritchett et al. (2002) humans are likely to be more eff icient at breaking down BPA due to relatively larger liver. The targets of the toxic effects of BPA are probably mitochondria and mitochondrial respiration (Nakagawa and Tayama, 2000). The sodium- potassium activated adenosine triphosphatase [Na + K + ATPase] is the enzyme responsible for the active transport of sodium and potassium ions to maintain the ionic gradient, Na + coupled transport of nutrients into cells, osmotic balance and regulation of cell volume (Zanatta et al., 2001). The role of environmental chemicals on mitochondria and mitochondrial metabolism has not been studied in detail in fish. The present study an attempt was made to screen the effect of BPA on the activity of mitochondrial Na + K + ATPase and Ca 2+ ATPase in the liver and gill and the activity of hepatic mitochondrial enzymes such as malate dehydrogenase [MDH] and isocitrate dehydrogenase [ICDH] in a freshwater fish, Anabas testudineus. Received on: 01.10.2013, accepted on: 10.11.2013 Journal of Aquatic Biology & Fisheries, Vol. 2(1) 2014: 122-128 © Department of Aquatic Biology & Fisheries, University of Kerala.