Synthesis and Antithyroid Activity of Some 8-Substituted Purine Derivatives

Some novel as well as known derivatives of 8-sulfanyl-3,9-dihydro-1H-purine-2,6-dione were synthesized and their antithyroid activity was measured in rats after administration of a daily dose of 20mg/kg via i.p. injection for 15 days. Free thyroxine and triiodothyronine concentrations were determined using radioimmunoassay technique. The assay results showed decrease in the hormonal concentrations for the animals treated with these compounds as compared to the control animals. Similarly, thyroid stimulating hormone level was measured with ELISA method and the results demonstrated a comparative increase of this hormone for the treated animals. The hormonal variations indicated significant (a <= 0.05) activity of the compounds. Histological study of thyroid tissues from the test animals showed cellular modifications in the treated animals like cylindrical shape of follicular epithelium, depletion of colloid and high values of thyroid body indices. All these factors further confirmed the antithyroid effects of the compounds under study.