Egypt. J. Exp. Biol. (Zool.), 5: 363 – 372 (2009) © The Egyptian Society of Experimental Biology ISSN: 2090 - 0511 On Line ISSN: 2090 - 0503 http://www.egyptseb.org RESEARCH ARTICLE Mohamed A. Basyony ROLE OF 2-MERCAPTOPROPIONYLGLYCINE IN MANAGEMENT OF HEPATIC DISORDER RATS EXPOSED TO LEAD INTOXICATION ABSTRACT: The efficacy of 2-Mercapto propionyglycine in management of lead toxicity in rats with carbon tetrachloride-induced hepatic disorder was evaluated at two level of intoxication; chronic (5 and 50 mg Pb/kg/dayx30) and one acute dose (LD 50 and 1/2 LD 50 ) . 2-MPG was given at a dose regimen of 50 mg/kg/dayx30. The LD 50 of lead for normal and for hepatic disordered rats as well as lead accumulation in hepatocytes and its impact on liver functions were the main criteria to monitor the efficacy of treatment. The study showed that lead had additive toxic stress to rats with liver disordered than to normal ones where it displayed an LD 50 of 1950 mg/kg for cirrhotic (hepatic disordered) rats compared to 3200 mg/kg for the normal ones. Significant accumulation of lead in hepatic cells with liver enlargement in hepatic disordered rats was recorded. Lead intoxication displayed further disorders in hepatic functions compared with non-intoxicated ones. More reductions in hepatic enzyme activities of 5'-nucleotidase, acetyl cholinesterase and aminotransferases in liver tissue were observed. Acetyl cholinesterase and 5'-nucleotidase in serum showed further decreased activities, while more elevations in hepatic alkaline phosphatase in addition to serum aminotransferases and alkaline phosphatase activities were detected. The toxic effects of lead were found to be more severe in acute rather than in chronic administration. Administration of 2-MPG showed appreciable protective effect against lead toxicity in hepatic disordered rats as manifested by marked reductions of the hepatic disorders and tissue lead accumulation in addition to improvement in relative liver weights. KEY WORDS: 2-Mercapto propionyglycine, Lead pollution, Heavy metals, hepatic disorder CORRESPONDANCE: Mohamed A. Basyony Zoology Department, Faculty of Science, Tanta University, Tanta, Egypt. E-mail: basyony@gmail.com ARTICLE CODE: 42.01.09 INTRODUCTION: Man has always been exposed to heavy metals through natural concentrations in soil, air and water. In areas with high concentrations, metallic contamination of food and water as well as inhalation of polluted air - probably led to unavoidable poisoning. The heavy metal ions are waste products of many industrial processes and in many places are released into rivers and oceans where they are important causes of atmospheric and environmental pollution (Marco et al ., 2001). In Egypt, heavy metal pollution has become one of the main problems confronting several industrial districts all over the country and has extremely increased in the last years. Among the many heavy metals, lead (Pb), cadmium (Cd) and mercury (Hg) are considered the three heavy metals widely recognized as the most toxic in our environment and can be detected in all plants, animals and microorganisms, where these toxic substances exceed the internationally agreed threshold levels for foodstuffs which, of course affect the human health. These metals are widely used in industry and enter the environment wherever they are produced, used and ultimately discarded (El-Shahawy and Mohamadein, 2000). Throughout human history, lead has been both a necessity and an evil. It has allowed for great civilizations to rise, and perhaps contributed to their demise. Its toxicity can be either acute and dramatic or chronic and subtle (Cziczo et al ., 2009). The annual production of lead has been estimated at about 500-fold the total amount of lead circulating in the entire earth's biomass. The estimated natural lead concentration in the air was about 0.0005 µg/m 3 , but in cities, lead concentrations in the air were 1000 to 10,000 folds greater and in many industrial areas, Pb concentrations in air may exceed 100 µg/m 3 . The dietary lead intake was found to be about 300 µg/day 100-folds more than the natural value (WHO, 1977). Lead is a ubiquitous element in the environment causing oxidative burst in the exposed individuals, induce a broad range of oxidative damage, physiological, biochemical, and behavioral dysfunctions in laboratory