ANALYSIS OF THYROIDAL ENZYMES ACTIVITY IN ZINC SUPPLEMENTED LITHIUM TREATED RATS

Abstract

Lithium is used in the therapy of manic depressive disorder. It affects cell function via its inhibitory action on several intracellular enzymes. Zinc, an essential trace element, has an important role in several biological activities. Therefore, present study was aimed at investigating role of zinc on thyroidal enzyme activities following lithium administration. Control group animals were given standard feed and tap water ad libitum. Lithium treated animals were fed lithium (LiCO3; 1.1g/kg body weight) through diet. Zinc treated rats were given zinc (ZnSO4.7H2O; 227 mg/L in drinking water). The treatments were given for 8 weeks. Monoamine oxidase activity was found to be significantly increased during lithium treatment. Thyroid peroxidase activity, however, was found to be significantly reduced in lithium treated group. However, combined lithium and zinc treatment showed a significant elevation in the enzyme activity. Coadministration of lithium and zinc also resulted in a significant depression in the Na+/K+ ATPase activity, thereby clearly indicating the effective role of zinc in regulating this activity. Zinc is playing an effective role in reducing the toxic effects of lithium in thyroid, possibly due to it’s antioxidative nature.