[Toxic effects of ammonium perchlorate on thyroid of rats].
OBJECTIVE
To study the effects of toxicity of ammonium perchlorate (AP) on thyroid of rats.


METHODS
Eighty-eight Wistar rats were treated orally with different dosages of AP. Three treated groups received 129, 257, 514 mg.kg(-1).d(-1) of AP respectively and one control group drunk water for 13 weeks. Another 3 groups received 1.2, 46.5, 465.0 mg.kg(-1).d(-1) of AP respectively and one control group drunk water for 36 weeks. The behavior and change of body weight in rats were observed. The levels of thyroid hormones in serum were measured and the pathological changes of thyroid tissue were observed as well.


RESULTS
There were no differences in behavior and change of body weight between different AP exposure time. When the rats were treated with AP 514 mg for 13 weeks, free triiodothyronine (FT3, 2.48 pmol/L), free thyroxin (FT4, 13.33 pmol/L) were lower than those in control group (3.24, 20.92 pmol/L respectively, P<0.05). Thyroid-stimulating hormone (TSH, 0.375 mIU/L), thyroglobulin (TG, 3.37 microg/L) were higher than those in control group (0.29 mIU/L, 2.00 microg/L respectively, P<0.05). When the rats were treated with AP 465 mg for 36 weeks, FT3 (2.65 pmol/L) was lower than that in control group (4.97 pmol/L, P<0.01). FT4 in 46.5, 465 mg groups (10.63, 2.17 pmol/L respectively) were lower than that in control group (15.74 pmol/L, P<0.05, P<0.01). TSH in 465 mg group (0.34 mIU/L) was higher than that in control group (0.14 mIU/L, P<0.05). Histopathologic examination showed that follicle proliferation, no colloid in follicle, gore, follicular diminishing or atresia were found in 46.5, 465 mg groups with a dose-effect relationship.


CONCLUSIONS
The toxic effects of AP on the growth of rats were not found, but those on the thyroid of rats were found significantly. Thyroid is the target organ of AP. It is considered that none effect dose of AP for rat thyroid may be 1.2 mg.kg(-1).d(-1), its threshold dose may be 46.5 mg.kg(-1).d(-1).
Peng
Kai-liang
KL
Institute of Industrial Toxicology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
Jiang
Yun
Y
Zhao
Su-li
SL
Zhang
Yan-rong
YR
Lu
Cui-rong
CR
Peng
De-hui
DH
Liu
Wei-dong
WD
D000818:Animals; D004305:Dose-Response Relationship, Drug; D005260:Female; D008297:Male; D010472:Perchlorates / Q000633:toxicity*; D000644:Quaternary Ammonium Compounds / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar; D013961:Thyroid Gland / Q000187:drug effects* / Q000473:pathology; D013963:Thyroid Hormones / Q000097:blood; D013972:Thyrotropin / Q000097:blood
D010472:Perchlorates; D000644:Quaternary Ammonium Compounds; D013963:Thyroid Hormones; D013972:Thyrotropin; C053506:ammonium perchlorate