Abstract
Background: Clomiphene citrate (CC) has been considered as the most effective drug to treat female infertility which is highly effective in inducing ovulation in females with anovulation or oligo-ovulation, however, it may induce partial inhibition of ovulation because of its inhibitory action on follicular growth and atresia of nonantral and mature follicles.
Objectives: The present experiment was conducted to study the effect of CC on follicular development (experiment 1) and superovulation (experiment 2) during the first follicular wave in Rahmani sheep with a 22-day ovulation cycle.
Patients and Methods: In experiment 1, the animals were divided into 2 groups, namely, control (n = 7) and CC (n = 6) groups. The estrous cycles of the animals in both groups were synchronized by administering two 15-mg/mL doses of Dinoprost at a 10-day interval. Onset of ovulation (day 0 [D0]) was confirmed by performing transrectal ultrasonography. The animals in the CC group received 100 mg of oral CC daily for 5 consecutive days. In experiment 2, the estrous cycles of the animals were synchronized as mentioned previously, and the animals were divided into 2 groups: (1) the equine chorionic gonadotropin (eCG) group (n = 4), in which the animals received 2000 IU of eCG intramuscularly (i. m.) for 5 days, and (2) the eCG and CC group (n = 5), in which the animals received 2000 IU of eCG i. m and 100 mg CC orally for 5 days.
Results: We observed a significant (P < 0.05) increase in the number of follicles from D2 to D5 and in the levels of estradiol (E2) from D1 to D4 after CC treatment, with no significant differences between the progesterone (P4) levels in both the groups. The increase in the number of follicles in the eCG and CC group was not as significant as that in the eCG group. The E2 level in the eCG group was significantly higher than that in the eCG and CC group from D1 to D3.
Conclusions: In conclusion, administration of CC increased the number of the growing follicles and plasma E2 levels. However, CC administered during superovulation did not increase the number of ovulating follicles and negatively affected the E2 level. Copyright (C) 2011 Kowsar M.P. Co. All rights reserved.