تاثير خوراكي سرب بر غلظت هورمونهاي تيروييدي و آنزيم‌هاي كبدي در موش صحرايي‌

Effect of lead on thyroid hormones andliver enzymes in adult male rats

Introduction: Lead is a heavy metal that could bean environmental pollutant. It is a natural metal that exists in water and soil, enters the body through digestive or respiratory systems. The researches showed that various amounts of lead has some effects on the endocrine glands and metabolic activities of the body. So, in this research, westudied and compared the effects of different amounts of leadon thyroid glandand liverenzymes in adultmalerats. Methods: 40 adult male wistar rats were studied in the from of experimental, sham and control groups. Experimental group was in divided into three subgroups and received lead acetate 25, 50, 100(mg/kg) by oral rate, in fifteen days. Shamgroups received distilled water and control group received nothing. At the end of the fifteenth day, blood samples were takenand concentrations of 1ʹ3, T4, TSH, AST, ALTand ALPwere measured. Results: The assessed results using Tukey Lest were studied. The findings after statistical analysis showed that concentration of T3 hormoneand enzymes of AST, ALT by receiving various amounts of lead acetate in comparison with control group show no significant difference, but concentration of TSH and ALP showeda significant reduction. Conclusion: According to above results and to findings and studies made by other researchers, lead has an effecr on thyroid hormones, causing damage to thyroid function by inhibiting deiodinarion of T4. Lead decreases the activity of MAOand acetylcholineasterase and in lhis way changes the pattern of releasing TSH. It decreases the release of TSH hormone by inhibition of dopamine uptake. We may conclude that leadhas sometoxiceffecton thyroid function and the liver as well.