ABSTRACT
Nicotine is an ingredient of cigarette smoke that has a lot of psychological and physical effects on addicted persons. The aim of this study was to evaluate nicotine effects on functional and histological alteration in thyroid gland that has important role on metabolic activities. In this experimental study, 40 mature male mice [25-30 gr] were divided to one control group and 3 experimental groups that received nicotine with dosage of 100, 200 and 400 micro g/kg via oral gavage once a day for 60 days. Then, T[3], T[4] and TSH serum levels were measured and histomorphometric evaluation of thyroid gland was done. Significant decrease in body weight and thyroid follicular epithelial height and significant increase in serum level of T[3] were noted. This study showed that nicotine can cause alteration on metabolic activities of thyroid gland via the increase of T[3] serum level and the decrease of follicular epithelial height