Oestrogen Receptors and Metabolic Activity in the Genital Tract After Ovariectomy of Ewes With Permanent Infertility Caused by Exposure to Phyto-Oestrogens

Abstract

Characteristics of the uterus anc cervix after ovariectomy of ewes with permanent phytooestrogen infertility (PPI) were compared with controls. Ewes with PPI had more oestrogen-binding sites in the cervix, but not in the uterus. There was no difference between the two groups of ewes in the binding affinity constant of receptors from the uterus or cervix. There were more keratinized cells in the vaginal epithelium of ewes with PPI, and the rates of protein and glycoprotein synthesis in the uterus and cervix were higher in ewes with PPI. These results offer further evidence that PPI in adult ewes is similar to the "persistent oestrus' syndrome in rodents oestrogenized neonatally.

Proportions of Nucleic Acids in the Uteri of Ewes with Clover Disease and the Effect of Oestrogen after Ovariectomy

“…It is not clear why the difference should take 3 days to appear, but the present study shows that a very similar phenomenon occurs in sheep with clover disease. Thus the results are consistent with the hypo!hesis (Tang and Adams 1981) that the changes which occur in clover disease are a result of the phyto-oestrogen having the type of differentiating action on the ewe which is normally seen with sex steroids on their target tissues during organogenesis. Since a similar change in responsiveness to oestrogen also occurs in the cervix, it is possible that this differentiating actionM the phyto-oestrogen is responsible for the functional abnormality in the cervix which results in infertility.…”

“…In the present study the uterine ratio of RNA to DNA was significantly greater in ovariectomized clover-affected ewes than controls. This and the fact that the uterus from ovariectomized clover-affected ewes has a higher rate of protein and glycoprotein synthesis (Tang and Adams 1981) indicate that the uteri of ovariectomized clover-affected ewes did not regress as much as did those of the control ewes and thus functioned as though still under slight oestrogenic stimulation. However, mild bacterial endometritis is common in ewes with clover infertility (Adams 1975) and this may have had some influence on the results.…”

“…Ovariectomized-affected ewes have an impaired responsiveness to repeated treatment with oestradiol benzoate which prevents the production of cervical mucus with a normal spinnbarkeit (Adams 1979) and the responsiveness of the hypothalamus to oestrogen is also slightly decreased (Adams 1978). Recently we reported that rates of protein and DNA synthesis were greater in the genital tracts of ovariectomized clover-affected ewes than in those of ovariectomized controls (Tang and Adams 1981). However, it is not known whether the uterus in clover-affected ewes responds normally to oestrogenic stimulation.…”

Sexual behaviour of ewes with clover disease treated repeatedly with oestradiol benzoate or testosterone propionate after ovariectomy

“…The uterine-like histological metaplasia of the cervix in affected ewes is best interpreted as an oestrogen-dependent differentiation (Lightfoot & Adams, 1979). In addition, ovariectomized affected ewes have increased protein and glycoprotein synthesis in the uterus and cervix and increased epithelial cell keratinization in the vagina, in the absence of any hormonal stimulation (Tang & Adams, 1981). Similar changes have been reported in female rodents treated neonatally (i.e.…”

“…The ewes in the present study and those of Adams (1976) and Tang & Adams (1981) had never been exposed to phyto-oestrogens until after puberty. Thus, the permanent effects of phytooestrogens on the ewe mimic at least some of the changes caused by hormonal steroids during differentiation, even though the phyto-oestrogens are administered outside the normal period of organogénesis.…”