OBJECTIVETo study the effects of ammonium perchlorate (AP) on the levels of thyroid hormone and the testis function of male rats.

METHODSTwenty male rats were randomly divided into 4 groups: control group, low, middle and high AP group. The rats were exposed orally to 0, 130, 260 and 520 mg AP/kg a day for 80 days. The levels of thyroid hormone, testosterone in serum and sperm motility were measured and the testis histological change was observed as well.

RESULTSThe increase of body weight in high AP group was significantly lower than that in the control group (P < 0.01). The organ coefficients of testis and thyroid in high AP group obviously enhanced, as compared with the control group (P < 0.01). The free thyroxin (FT4) levels of serum in all AP treated groups were significantly lower than that of the control group (P < 0.05). There were no differences of serum FT3 levels between all AP groups and control group, while serum TSH levels in middle and high AP groups decreased significantly, as compared with control group (P < 0.01). In terms of sperm motility, the percentage of Grade A and B sperm in middle and high groups were 12.3% +/- 2.52% and 14.8% +/- 5.93%, 17.7% +/- 4.63%, 15.8% +/- 2.28% respectively, which were significantly lower than that (27.8% +/- 8.70%) in control group (P < 0.01). The percentage of Grade D sperm in middle and high groups were 38.0% +/- 3.61% and 40.0% +/- 8.99%, respectively, which were significantly higher than that (17.0% +/- 5.00%) in control group (P < 0.01). No difference of serum testosterone level between all AP groups and control group was observed.

CONCLUSIONAP can influence the levels of thyroid hormone and reduce the serum FT4 levels in rats. The main toxic effects on male reproductive system may decrease the sperm motility.