MSc Thesis The Effect of Paraquat on Adenosine Deaminase Activity in Different Tissues of Mice (Mus musculus - Swiss Albino) Fikriye POLAT Cumhuriyet University Graduate School of Natural and Applied Sciences Department of Biology Supervisor : Yrd.Doç.Dr.Egemen DERE Iıı this study, the effects of a LD30 (20 mg.kg-1) dose of paraquat, a herbiside, have been investigated on adenosine deaminase activity in the liver, kidney and lung of mice after 2, 4, 8, 16, 32, 64 and 72 hours it was applied intraperitoneally to Mus musculus swiss albino mice. Paraquat did not cause an important change on the adenosine deaminase activity in the liver and kidney. While adenosine deaminase of the livers constantly showed parallelism with the control group, some insignificant increase and decrease has been found on the adenosine deaminase levels of the kidney. However, in the lungs, while adenosine deaminase enzyme activity showed a significant inhibition in the initial phase, it was placed by activation after 16th hour, and statistically significant increase (in the adenosine deaminase enzyme activity) was found in the 64th and 72nd hours. Key Words : Paraquat, Adenosine Deaminase