Abstract

The relationship between the thyroid function and some fertility parameters in male rats were studied. 18 albino rats (age 40-50 day) divided equally in to three groups: the 1^st group was administered levothyroxine T4 (1mg/kg BW) orally for 10 successive days to induce hyperthyroidism, the 2^nd group was administered carbimazole (5mg/0.25 kg BW) orally for 21 successive days to induce hypothyroidism, while the third group administered with normal saline orally for 21 days (control group). Then the weight of the body, testis, body and tail of epididymis, accessory glands, number of sperms, sperm abnormalities, percentage ratio of life and dead sperms, concentration of T4 in serum were calculated and the histopathological changes of the testis were observed at 60 day after treatment. The results showed significant increase of the number of sperms in the 1^st group in comparison with control group. The sperm abnormalities increased significantly in the 1^st and 2^nd group while the number of life sperms decreased significantly in these groups in comparison with control group. The concentration of T4 increased significantly in 1^st group at 15 day of experiment while there is no change in concentration of T4 at 60 day of experiment in both 1^st and 2^nd groups. The histopathy of testis include degeneration and necrosis of Sertoli cells in the 1^st group and destroying the basal membrane of seminifrous tubules with necrosis of Sertoli cells in the 2^nd group.