ABSTRACT

The antiuterotrophic efficacy of the pure antioestrogen ICI 182,780 has been demonstrated previously by magnetic resonance imaging (MRI) in ovariectomized oestrogen-treated monkeys (Macaca nemestrina). Further characterization of the effects of ICI 182,780 in intact adult female monkeys with normal menstrual cycles was undertaken to provide an indication of its potential actions in premenopausal women. Changes in the volume of uterine tissues were measured by MRI in early, mid and late cycle. The volume of the uterus varied up to fivefold between individual monkeys but serial observations in individuals provided sufficient precision to allow accurate assessments to be made of changes in the endometrium and myometrium during the course of the menstrual cycle and following ICI 182,780 administration. In comparison with its initial size in untreated monkeys, the endometrium increased in volume by 60% and 125% in the mid and late cycle respectively. In contrast, the size of the myometrium decreased significantly, by 16% from early to mid cycle and then recovered to near its initial volume in the late cycle. Treatment with ICI 182,780 beginning in the early part of the menstrual cycle prevented the growth of the uterus. The magnitude and duration of the response was dependent on whether or not ovulation occurred during treatment with ICI 182,780. In animals rendered anovulatory, growth of the endometrium was blocked completely by ICI 182,780 and the volume of the tissue declined below that present at the start of the menstrual cycle. Antiuterotrophic efficacy was significantly less in monkeys which ovulated during treatment with ICI 182,780. The volume of myometrium was reduced substantially by antioestrogen treatment, and the difference in response between ovulatory and anovulatory monkeys was less marked than that of the endometrium.

Journal of Endocrinology (1993) 138, 203–209

ABSTRACT

We have previously shown that pregnancy-associated endometrial α₁-globulin, a small molecular weight insulin-like growth factor-binding protein (IGF-BP), is quantitatively the major secretory protein product of the decidualized endometrium during human pregnancy. In the present study, employing monoclonal antibodies raised against this protein in an immunohistological technique, the cellular localization of the protein has been examined in the decidua and placenta during pregnancy. During the first trimester the protein was principally associated with the decidual cell in the decidualized decidua compacta region of the endometrium with both cytoplasmic and extracellular matrix-associated staining patterns being detected. No extensive staining was observed in the placenta. At term the protein was localized in similar cells in the placental bed and endometrium associated with the amniochorion but not in the placenta. These studies suggest that the decidual cell represents the major source of IGF-BP during pregnancy and have relevance to the origin of amniotic fluid IGF-BP and the paracrine role of the decidual cell in the control of trophoblast growth.

Journal of Endocrinology (1989) 120, 351–357

ABSTRACT

Oestrogen induces a migration of eosinophil leukocytes to the uterus where, it is suggested, these cells mediate several responses to hormone stimulation. To investigate the mechanism of the recognition of the uterus by the eosinophils, the present study describes the effect of a blockade of the rat reticulo-endothelial system with colloidal carbon on oestrogen-induced uterine eosinophilia, and other responses to oestrogen stimulation that, it has been suggested, are mediated by eosinophils.

In the absence of oestrogen colloidal carbon induced an increase in the number of eosinophils in mesometrium but not in endometrium with myometrium, and a slight oedematous reaction in deep endometrium. Colloidal carbon abolished the oestrogen-induced increase in the number of eosinophils in endometrium with myometrium and drastically decreased the oestrogen-induced increase in uterine wet weight and the endometrial oedematous responses 6 h after the administration of oestrogen.

The present results agree with the hypothesis that most uterine water imbibition is mediated by eosinophils and suggest a possible mechanism for the interaction of colloidal carbon with eosinophil migration to the uterus.

J. Endocr. (1986) 109, 89–95

SUMMARY

The uptake of [6,7-³H]oestradiol by the reproductive tract was studied in 18 non-pregnant women who were undergoing hysterectomy for conditions not associated with an abnormal endometrium. A single s.c. injection of 50 μc [6,7-³H]oestradiol (specific activity, 182 μc/μg.) was given 2 hr. before hysterectomy. Tissue samples were dissolved in 5 n-alkali and their radioactivity content determined by liquid scintillation counting. Total and free steroid (ether soluble) radioactivities in the plasma were also determined. The existence of an essentially normal menstrual cycle in these patients was confirmed by histological examination of tissue samples and, in some cases, by determinations of urinary pregnanediol. Urinary total radioactivity was within the normal range, except in one case, thus confirming normal oestrogen metabolism.

The radioactivity content of the tissues of the reproductive tract was well above that attributable to their plasma content. In some cases the uptake by different regions of the endometrium varied considerably. In the follicular phase of the menstrual cycle uptake was higher than that in the luteal phase. Vaginal and cervical epithelium showed variable uptake but in general it was lower than that for endometrium.

Cell fractionation studies showed that, in general, proportionally more of the endometrial radioactivity was associated with the nuclei in the follicular phase than in the luteal phase.

SUMMARY

The activity of several enzymes has been measured in the uterine endometrium of the rabbit during oestrus and pseudopregnancy and after injecting oestradiol benzoate or progesterone 28 days after ovariectomy. The enzyme activity of the uterine fluid has been determined during oestrus and the effect of uterine ligation studied.

Progesterone and the induction of pseudopregnancy stimulated succinic dehydrogenase (SDH) and glucose-6-phosphate dehydrogenase (GDH) activity and depressed amylase and lactic dehydrogenase (LDH) activity. In ovariectomized does, glutamate-oxaloacetate transaminase (GOT) activity increased after the injection of progesterone. Progesterone also stimulated endometrial phosphatase after ovariectomy but, when given after a period of oestrogen treatment, it limited the even greater response of acid and alkaline phosphatase to oestrogen; the activity then attaining the same level as when progesterone alone was given.

SDH, GDH and glycerylphosphorylcholine (GPC) diesterase could not be detected in uterine fluid but amylase and alkaline phosphatase were in greater concentration than in the endometrium. GPC diesterase was, however, found to be present in uterine tissue. Ligation of the uterus did not significantly alter the enzyme activity of the endometrium.

Concentrations of prostaglandin F_2α (PGF_2α) and prostaglandin E (PGE) were measured in endometrium from 18 women with ectopic pregnancies. In the nine pregnancies not associated with vaginal bleeding or an intra-uterine contraceptive device (IUCD; intact ectopics), concentrations of PGF_2α (12·8 ± 7·4 (s.e.m.) ng/g) and PGE (4·7 ± 3·0 ng/g) were similar to those in decidua from nine intra-uterine pregnancies of comparable gestational age (14·4 ± 4·4 and 8·2 ± 2·2 ng/g respectively). In both ectopic and intra-uterine pregnancies concentrations of prostaglandins were significantly lower than those found in endometrium throughout the normal menstrual cycle (P < 0·01). In nine ectopic pregnancies with associated vaginal bleeding and/or an IUCD, concentrations of PGF_2α and PGE were significantly higher than in the intact group (P < 0·05), although the concentration of PGF_2α remained significantly lower than levels in normal secretory endometrium (P < 0·05).

These results suggested that suppression of endometrial synthesis of prostaglandin during early pregnancy may be mediated systemically rather than through a local action of the conceptus.

Abstract

A glycoprotein, termed GP42, was previously identified in uterine fluid obtained from peri-implantation-stage rabbits. N-terminus amino acid sequencing of purified GP42 demonstrated identity through the first 13 amino acids with the β subunit of liver haptoglobin. The present study was undertaken to determine if GP42 is indeed identical to haptoglobin and, if so, to determine whether it is expressed in the uterus as opposed to being present as a transudate from plasma. Reverse transcription-PCR amplification of poly(A)⁺ RNA prepared from implantation-stage rabbit endometrium with GP42- and haptoglobin-specific primers yielded a predicted 667 bp cDNA product. Sequence analysis of the cloned cDNA confirmed the identity of GP42 with β-haptoglobin. Northern blot analysis demonstrated the specific expression of haptoglobin mRNA in the peri-implantation-stage endometrium and the absence of its expression in the estrous or day 4 pseudopregnant endometrium. Non-isotopic in situ hybridization revealed that the haptoglobin mRNA was restricted to the epithelium lining the luminal surface and mucosal folds of day 6¾ pregnant or pseudopregnant uteri and that no haptoglobin mRNA was detectable in the epithelium of the deep glands or cells of the stroma or myometrium. Similarly, in situ hybridization revealed no expression of haptoglobin mRNA in any cell types of the estrous uterus. These data establish the identity of GP42 with β-haptoglobin and demonstrate that it is expressed in a stage-specific manner just prior to implantation, correlating with uterine receptivity to blastocyst implantation. Endometrial GP42 mRNA expression is not dependent on the presence of blastocysts.

Journal of Endocrinology (1997) 152, 69–80

In the ovine endometrium, dramatic increases in gastrin-releasing peptide (GRP) mRNA and immunoreactivity are observed during the luteal regression phase of the oestrous cycle (24-fold) and during pregnancy (at least 150-fold). This study sought to determine whether oestrogen and/or progesterone were responsible for the temporal regulation of GRP observed in the uterus. Ovariectomized sheep were divided into four groups (n=4), as follows: 1, untreated; 2, given subcutaneous and intravaginal progesterone implants; 3, given subcutaneous oestrogen implants; and 4, treated with both oestrogen and progesterone. After 10 days, the animals were sacrificed and plasma, pituitary and endometrium were obtained. A fifth group of sheep with intact ovaries was included. Analysis of endometrial GRP-immunoreactivity (GRP-ir) revealed a twofold drop for groups treated with oestrogen, progesterone or both hormones. A dramatic reduction in endometrial GRP mRNA was o! bserved in the group treated with both hormones. GRP-ir was measured in whole pituitaries and found to vary greatly (1.7-53.7 pmol/g tissue) within all groups of ovariectomized animals. There were no significant differences between any of the five groups. A significant reduction in circulating GRP-ir was observed after 10 days of treatment with either oestrogen or progesterone. These studies demonstrate that, in sheep, the synthesis, storage and secretion of GRP are differentially affected by oestrogen and progesterone. Regulation appears to be tissue specific since GRP content in the pituitary is unchanged by oestrogen or progesterone whereas GRP expression in the endometrium is inhibited. Changes in GRP mRNA expression did not correlate with changes in endometrial expression of mRNA for oestrogen receptor alpha, oestrogen receptor beta and the progesterone receptor. This study is the first reported demonstration that expression of the GRP gene can be influenced by the presence of ovarian steroids, with the conclusion that oestrogen and/or progesterone act as negative regulators of endometrial GRP expression.

SUMMARY

Carbonic anhydrase was shown to occur in the female reproductive tract of a variety of mammalian species. The uterine endometrium, placental tissue and the Fallopian tubes were established as the main loci of carbonic anhydrase activity.

The enzyme was present in the endometrium of the non-pregnant rabbit in a low concentration. Following mating no perceptible increase in enzyme content occurred before the 4th day; from then onwards the activity continued to rise, reaching a maximum by about the 8th day; with advancing foetal development the endometrial activity declined, but at the same time the enzyme could be demonstrated in the placenta, chiefly in the maternal, but to a small extent also in the foetal, part.

The behaviour of carbonic anhydrase in the pseudopregnant uterus or in response to ovulating doses of gonadotrophin or copper salts, presented essentially the same picture as in the early phase of pregnancy; excessive doses of gonadotrophin were capable of increasing the enzyme content within 2 days of administration; moreover, their effect persisted for 20–24 days.

Progesterone, and to a smaller extent ethisterone and methyltestosterone, injected into oestrous adult or into oestrogen-primed immature rabbits, produced marked increases in the content of uterine carbonic anhydrase, the extent of which depended upon the dose.

Whereas the endometrium of rats, hamsters and guinea-pigs was completely devoid of carbonic anhydrase, both in pregnant and non-pregnant females, the placenta of these animals contained the enzyme, again mainly in the maternal portion.

The uterine mucosa of the non-pregnant sheep was conspicuously rich in carbonic anhydrase, the activity being largely restricted to the intercotyledonary areas; the uterine portion of the Fallopian tubes was also remarkably active. In this species the uterine carbonic anhydrase was found to be independent of ovarian function: the enzyme was present in the uteri of prepubertal lambs, and it was fully preserved in ovariectomized animals. Considerable enzymic activity was found in the sheep placenta.

No carbonic anhydrase was found in the uterus or Fallopian tubes of the non-pregnant pig; the pig placenta, however, was very active, the enzyme being located in the chorion in late pregnancy.

In the non-pregnant cow only the fimbrial portion of the Fallopian tubes showed enzymic activity, especially marked in the immediate post-ovulatory phase. No carbonic anhydrase was present in the non-pregnant uteri or Fallopian tubes of mares, cats or dogs.

By introducing parenterally large amounts of a sulphonamide inhibitor of carbonic anhydrase it was possible to inhibit the enzyme in vivo, both in the rat placenta and in the progestational rabbit endometrium.

SUMMARY

In ovariectomized rats progesterone acts like oestradiol at the endometrial, but not at the myometrial level, by increasing the number of oestrogen receptors in the cytoplasm. After 3 days of progesterone priming, the number of endometrial oestrogen receptors was found to be three times higher (P<0·05, Student's t-test) than control values. This progesterone-induced oestrogen receptor molecule appears identical in its physicochemical properties (sedimentation coefficient, kinetic constants, steroid specificity) to that induced in the endometrium and myometrium under the influence of oestradiol. However, in the myometrium progesterone acts antagonistically reducing significantly (P< 0·001, Student's t-test) the oestradiol-induced increase in the number of oestrogen receptors.