Effects of Nonylphenol on the Structure and Function of the Thyroid Gland in Rats

Objective:To study the effects of different concentrations of nonylphenol(NP) on the structure and function of the thyroid gland in rats.Methods:Forty healthy 4-week-old SD rats were randomly divided into 4 groups,each group comprised of 5 male and 5 female rats.The treated rats were administered different doses of NP(40 mg/kg,80 mg/kg and 200 mg/kg) by pouring stomach.The changes in serum hormones,histopathology and histochemistry results were examined after 15 days of treatment.Results:The hyperplastic thyroid structure was observed in all groups.The activity of succinic dehydrogenase(SDH) was increased obviously in dose dependent.The serum levels of FT3 and FT4 decreased gradually,and the serum level of thyrotropin(TSH) increased gradually in NP groups,compared with those of control(P 0.05).There were significant differences in serum levels of TSH,FT3 and FT4 between 40 mg/kg,80 mg/kg and 200 mg/kg of NP groups(P 0.05),but no significant differences between 80 mg/kg and 200 mg/kg NP groups(P 0.05).Conclusion:Nonylphenol could cause hypothyroidism in rats.