The effects of IUDs on the occurrence of ovulation and the pituitary gonadotrophin content was studied in water buffalo heifers of the Surti breed. Thirty-six of these heifers were divided into four equal groups. Group 1 received sham operations, while Groups 2, 3 and 4 were fitted with plastic IUDs in the cranial region of the uterus either ipsilaterally or contralaterally (in relation to the side on which ovulation occurred) or bilaterally, 72 hr after the exhibition of heat. Treated heifers showed significantly shorter cycles than the controls (P<0-01). There was no difference between Groups 2, 3 and 4. Heifers were slaughtered after the onset of heat in post-IUD-insertion cycles. Eight of the nine heifers ovulated in the control group, but only three in the group fitted with bilateral IUDs and one each in the groups fitted with ipsilateral and contralateral IUDs. The other ovarian characters studied did not show any significant differences among the four groups.The anterior pituitaries from these heifers in different groups were freeze-dried and assayed for lh and fsh. Neither lh nor fsh activity was statistically different among treatment groups.The results of this experiment suggested that an IUD, when present in one horn, also affects the adjacent ovary of the opposite horn to induce shorter cycles. This contralateral effect may be mediated systemically either at the level of the pituitary, the hypothalamus, or both. It is not possible to rule out transmission of a uterine factor from the IUDhorn to the non-IUD horn.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.