IOSR Journal of Computer Engineering (IOSR-JCE) e-ISSN: 2278-0661,p-ISSN: 2278-8727, Volume 18, Issue 4, Ver. I (Jul.-Aug. 2016), PP 37-42 www.iosrjournals.org DOI: 10.9790/0661-1804013742 www.iosrjournals.org 37 | Page The interplay of antioxidant activities in rats exposed to sub chronic low level inorganic mercury is gender specific Wusu A. D. 1*, Ogunrinola O. O. 1 , Ojekale, A.B 1 , Olaitan S. 1 , Onwordi, C.T 2 , and Auta, R 3 1 Biochemistry and 2 Chemistry Department, Lagos State University, Lagos, Nigeria, 3 Biochemistry Department, Kaduna State University, Kaduna Nigeria Abstract: To investigate sex differences in the effects of inorganic mercury on antioxidant enzymes in different compartments, male and female albino rats were exposed to mercury (0.5, 1.0 and 1.5mg/kg) for 12 weeks. Post exposure, total mercury in liver, kidney and whole blood was determined using Inductively-Coupled Plasma Spectrometry (ICP-MS) while superoxide dismutase (SOD) and catalase (CAT) activities in the liver, kidney, plasma and erythrocytes were also determined. Inhibition of CAT and SOD in plasma and erythrocyte characterized the effects of inorganic mercury in female animals with the same trend in SOD of the male, but vice versa in CAT respectively. Inorganic mercury exposure inhibited CAT by 23% (liver) and 84% (kidney); SOD by 30% (liver) and 16% (kidney) respectively in female animals. In the male animals, a 26% inhibition of SOD was observed in the liver, whereas CAT was inhibited (66%) in the kidney. Correlation analysis shows a negative relationship between tissue mercury levels and the two antioxidant enzymes specifically in females. The findings from this support sex differences in the effects of mercury on the depletion of antioxidant enzymes. Keywords: Inorganic mercury, Antioxidant enzymes, superoxide dismutase (SOD), Catalase (CAT). I. Introduction Mercury is the second-most prevalent heavy metal toxicant. It is of ubiquitous environmental and epidemiological importance, posing severe health risk to millions of people worldwide (Patrick 2002). Mercury toxicity has intense neurological, renal, cellular, cardiovascular, pulmonary, haematological, respiratory, immune, dermatological, reproductive and developmental disorders implications (Rice et al. 2014; Risher and Amler 2005). The toxicity of mercury depends on its chemical form. Mercury is found in the environment in three major forms, viz: elemental mercury, organic mercury and inorganic mercury compounds or mercury salts example eg. mercuric chloride (HgCl 2 ) (Magos and Clarkson 2006). Mercuric chloride (HgCl 2 ) is an inorganic compound with extensive applications in various field such as: catalyst in polyvinylchloride production, in sample preservation, photography etc. It is equally a widespread environmental and industrial pollutant, which induces severe alterations in tissues and enzyme functions of both animals and men (Mahboob et al. 2001). Exposure to inorganic mercury compounds (HgCl 2 ) had increased through its extensive usage in a range of medical and cosmetic products such as antiseptics, laxatives, diuretics, teething powders, skin-lighting creams (Syversen and Kaur 2012). Once absorbed, HgCl 2 is distributed in all tissues, and low fractions have been shown to easily cross the brain-blood barrier and the placenta. Critical target organs of mercury chloride exposure include kidney, liver, blood, intestinal epithelium and lungs (Berlin 1978; Warfvinge et al. 1992). The kidney is however considered as the primary target organ, in which HgCl 2 is intensively accumulated following chronic exposure (WHO 1991). Mercury and its compounds mainly inhibit the activities of the free radical quenching enzymes; catalase, superoxide dismutase and glutathione peroxidase (Benov et al. 1990) Different mechanisms have been highlighted to account for the biological toxicity of mercury chloride (Sener et al. 2007). Beside the reported affinity of mercury chloride for thiol containing enzymes, a common factor in these mechanisms is the excessive generation of reactive Oxygen species, manifesting as increased lipid peroxidation in the cells (Durak et al. 2010b). Significant reductions in glutathione levels, GSH-Px, GST and catalase activities of the liver have been reported to accompany increased oxidative stress and lipid peroxidation (Temmar et al. 2013) There is a dearth of literature on sex differences in mercury chloride induced oxidative stress, though there is increased evidence that the effects of metal induced oxidative stress on health are manifested differently in males and females (Vahter et al. 2007). Higher resting plasma antioxidant levels have been observed in women compared with men (Goldfarb et al. 2007). Females have also been shown to have higher levels of mitochondrial reduced glutathione, SOD and glutathione peroxidase than their male counterparts. Similarly, mitochondrial from female rats has higher expression of antioxidants enzymes and lower production of reactive oxygen species compared to mitochondria of male rats (Borras et al. 2003).