Regulation of estrogen and progesterone receptor levels in epithelium and stroma from pre- and postmenopausal endometria

Morphometric analysis of the uterine endometrium of swine on days 12 and 16 postestrus

The uterine endometrium of swine is comprised of luminal epithelial, glandular epithelial, and stromal cells that secrete the luteolysin, prostaglandin F(2alpha) (PGF(2alpha)), during late diestrus. However, which of these cells contribute the most to luteolytic PGF(2alpha) secretion is unknown because the cellular composition of the endometrium has not been quantified. Therefore, this study quantified the cellular composition of the endometrium on days 12 and 16 postestrus by histologic and morphometric analyses. On day 12, the endometrium consisted predominantly of stromal cells (47% of total cell quantity) and glandular epithelial cells (37%), whereas luminal epithelial cells represented only 16% of the total of the three cell types. The number of glandular epithelial cells tended to increase (P < 0.10) between days 12 and 16, such that they comprised 45% of the endometrium by day 16, while the number of stromal and luminal cells did not change and accounted for 45% and 10% of the cells, respectively. Luminal epithelial cells had a 58% greater cross-sectional area (P < 0.001) than glandular epithelial cells, whereas glandular epithelial cells had a 22% greater area (P < 0.001) than stromal cells. Glandular epithelial cells decreased (P < 0.001) in cross-sectional area between days 12 and 16, whereas the area of luminal epithelial and stromal cells remained unchanged. These results indicate that the porcine endometrium is comprised predominantly of stromal and glandular epithelial cells that are likely to contribute substantially to endometrial PGF(2alpha) secretion during luteolysis. The contribution of glandular epithelium to luteolytic PGF(2alpha) secretion probably increases during diestrus as the number of these cells increases.

Exogenous sex hormone use, correlates of endogenous hormone levels, and the incidence of histologic types of sarcoma of the uterus

BACKGROUND

We analyzed data from a population-based, multi-center, case-control study to determine whether the occurrence of histologic types of uterine sarcoma is related to exogenous hormone use and/or to two correlates of endogenous estrogens: excess weight and cigarette smoking.

METHODS

One hundred sixty-seven women with newly-diagnosed uterine sarcoma (56 leiomyosarcoma, 85 mixed mullerian tumors, and 26 endometrial stromal sarcomas) were interviewed by telephone regarding possible risk factors for these neoplasms, For comparison, 208 women identified at random from the general population of the study areas were interviewed as controls.

RESULTS

Use of oral contraceptives was positively associated with the risk of leiomyosarcoma (odds ratios [OR] = 1.7, 95% confidence interval [CI] = 0.7, 4.1), primarily among women who last used these medications 15 or more years prior to diagnosis. Use of noncontraceptive estrogens was directly associated with the risk of mixed mullerian tumors, but only among recent and long-term users of these medications. Women in the highest quantile of body mass index (> or = 27.5 kg/m2) one year prior to diagnosis were at increased risk of each type of uterine sarcoma (leiomyosarcoma, OR = 2.5, 95% CI = 1.1, 5.7; mixed mullerian tumors, OR = 2.9, 95% CI = 1.3, 6.7; stromal sarcoma, OR = 3.5, 95% CI = 1.1, 10.9). Women who had ever smoked cigarettes were at reduced risk of leiomyosarcoma (OR = 0.6, 95% CI = 0.3, 1.1) and stromal sarcoma (OR = 0.5, 95% CI = 0.2, 1.2), but the relationship was not more pronounced among heavy smokers; no association with smoking was observed with mixed mullerian tumors.

CONCLUSIONS

Several of these findings parallel those from studies of endometrial carcinoma and may indicate a role for unopposed estrogen in the etiology of histologic types of uterine sarcoma.

Dysfunctional uterine bleeding (DUB)

Cyclic or irregular uterine bleeding is common in perimenarchal and perimenopausal women with or without endometrial hyperplasia. The disturbance often requires surgical treatment because of its negative effects on both blood loss and abnormal endometrial growth including the development of endometrial cancer. The endometrium is often overstimulated during the perimenopausal period when estrogen/progesterone production is unbalanced. A therapeutical approach with gonadotropin-releasing hormone agonist (GnRHa) was proposed in a depot formulation (Zoladex) that induces a sustained and reversible ovarian suppression. To avoid the risk of osteoporosis and to obtain adequate endometrial proliferation and differentiation during ovarian suppression, transdermal 17-beta-estradiol and oral progestin were administered. Results of 20 cases versus 20 controls showed a reduction of metrorrhagia, a normalization of hemoglobin plasma concentration, and an adequate proliferation and secretory differentiation of the endometrium of patients with abnormal endometrial growth. Abnormal uterine bleeding is mainly due to uterine fibrosis and an inadequate estrogen and/or progesterone production or to a disordered estrogen transport from blood into the endometrium. In premenopausal women, endometrial hyperplasia may be part of a continuum that is ultimately manifested in the histological and biological pattern of endometrial carcinoma. The regression of endometrial hyperplasia obtained by using the therapeutic regimen mentioned above represents a preventive measure for endometrial cancer. Finally the normalization of blood loss offers a good medical alternative to surgery for patients with DUB.

Endometrial effects during hormone replacement therapy with a sequential oestradiol valerate/cyproterone acetate preparation

Three sequential oestradiol valerate (E2V) and cyproterone acetate (CPA) combinations based on 11 days of oestrogen and 10 days of oestrogen-progestogen administration were investigated during hormone replacement therapy in two prospective, double-blind randomized trials. Treatment A comprised 2 mg E2V and 1 mg CPA, treatment B, 1 mg and 0.5 mg and treatment C, 2 mg and 2 mg, respectively. During treatment A hot flushes (P < 0.0001), night sweating (P < 0.0001), depression (P = 0.0001), dizziness (P = 0.0001) and insomnia (P = 0.003) decreased significantly. The only side effect was breast tenderness, which was experienced by 18% of the women. Weight and blood pressure, thyroid, adrenal, liver and kidney functions, parathyroid hormone and vitamin D, platelets and blood cell counts did not change during the 12 months of therapy. In the women who received treatment A the menstrual flow became less abundant during the early months of treatment (P < 0.0001), the menses being scanty in around 30% of the women, while some 10% had amenorrhoea. Spotting occurred in 10-20% of the subjects. Endometrial biopsies were atrophic in 10% of the women, whereas a normal secretory phase was observed in 45% and irregular secretion in 45%. After careful analysis using visual analog scales, these findings were interpreted as indicating a high-normal progestational effect. In comparison with the pattern observed in normal menstrual cycles the women who received treatment A had a more heterogenic glandular epithelium, with more papillae, larger stromal cells, a more pronounced decidual reaction and more fibrinoid material. No cases of hyperplasia were seen. Treatment B was less effective than treatment A in relieving climacteric complaints. Irregular bleeding was troublesome in over 20% of cases and amenorrhoea occurred in 50%. Endometrial biopsies were atrophic in 57% of the women. The effectiveness of treatment C in alleviating flushes, sweating, dizziness and depression was the same as that of treatment A. The decrease in menstrual flow during the early months and the incidence of amenorrhoea (approx. 10%) and atrophic endometria (approx. 10%) were comparable. Detailed analysis revealed that C had an even stronger progestational effect than A. It was concluded that A was the treatment of choice in comparison with B and C. It proved highly effective in treating climacteric complaints, had no side effects apart from breast tenderness, provided good cycle control and induced a physiological secretory transformation of the endometrium.(ABSTRACT TRUNCATED AT 400 WORDS)

Effect of Medroxyprogesterone Acetate on Immunohistochemical Expression of Estradiol in Endometrial Carcinoma

The effect of medroxyprogesterone acetate (MPA) on the immunohistochemical expression of estradiol (E2) was investigated in 25 cases of endometrial carcinoma. Twenty-three cases of the endometrial carcinomas showed positive Immunoreactivity for E2. The immunohistochemical expression of E2 was more intensive in carcinoma cells than in stromal cells. Although the morphologic alterations induced by MPA treatment were observed only in 2 cases who were administered more than 30,000 mg of MPA, the staining intensity in most cases appeared to decrease after the treatment. The decrease in E2 immunoreactivities of cancer cells as well as of stromal cells in Grade 1 or Grade 2 was significant. These results suggest that MPA might decrease the E2 content in endometrial carcinoma cells as well as in stromal cells.

Steroid binding alterations in tissue compartments of the vagina of control and neonatally diethylstilbestrol-treated adult mice

Steroid binding in both the vaginal epithelium and the vaginal fibromuscular wall (FMW) was compared in control and neonatally estrogen-treated mice. Neonatal treatment with a low dose of the estrogen diethylstilbestrol (DES) had no significant effect on adult estrogen binding within the assayed vaginal compartments; however, this treatment caused a 2-fold increase in the level of cytosolic progestin binding in the vaginal FMW over that in vehicle-treated mice. This low neonatal dose did not affect the level of progestin binding in the vaginal epithelium. In contrast, neonatal treatment with a larger dose of DES caused marked increases in cytosolic progestin binding, decreases in cytosolic estrogen binding, and increases in nuclear estrogen binding within the FMW. Furthermore, as a result of the changes in specific binding induced by the neonatal DES treatment, the degree of the estrogen binding within in each tissue shifted from a predominantly cytosolic site to a nuclear one.

The histochemistry of isocitric and oestradiol-17 beta dehydrogenases in the endometrium of postmenopausal women treated with oestrogens and progestogens

Endometrium was obtained from postmenopausal women during treatment with either oestrogen alone or on the third, sixth, tenth or twelfth day of combined therapy with oestrogens and progestogens. The activities of oestradiol-17 beta and isocitric dehydrogenases were measured in homogenates of the whole tissue and the enzymes were also located histochemically. Oestradiol dehydrogenase was located exclusively within the epithelium, whilst isocitric dehydrogenase was found in both epithelium and stroma, and also in stromal arterioles. Histochemically, oestradiol dehydrogenase was found in all the specimens which exhibited biochemical activity but in none of those from which it was absent. Isocitric dehydrogenase however, was seen in all tissue sections despite widely varying levels of biochemical activity in the homogenate. The method for measuring isocitric dehydrogenase activity was therefore nonspecific, whilst that for oestradiol dehydrogenase was reliable and low levels of enzyme activity could be detected. The latter technique may therefore be useful to predict the sensitivity of endometrial carcinomata to progestogens.

The effects of the addition of nomegestrol acetate to post-menopausal oestrogen therapy

Progestogens are added to the oestrogen treatment for 10-12 days each cycle in order to prevent endometrial abnormalities. However, concern has been expressed about the safety of certain of the currently available progestogens because of the potential adverse metabolic effects. We have evaluated the effects of nomegestrol acetate - non-androgenic progestogen - for administration to post-menopausal oestrogen users. Thirty-six (36) women receiving 50 mg oestradiol implants at regular intervals also took nomegestrol acetate for 12 days each calendar month at doses of 0.5 mg, 1.0 mg and 2.5 mg daily. Allocation to one of the dose regimens was random. Physical and psychological side-effects were recorded and all vaginal bleeding was noted: an endometrial biopsy was performed on the sixth day of progestogen addition for histological, ultrastructural and biochemical evaluation. Adverse side-effects were responsible for a dose-dependent drop out rates of 17%. All patients experienced a regular, progestogen-induced withdrawal bleed each month; and histological, ultrastructural and biochemical changes were induced within the endometrium by all 3 doses. Nomegestrol acetate is a potent progestogen and further studies are required to determine its lowest effective dose.

Immunohistochemical study of distribution of estrogen receptors in corpus and cervix uteri

An immunohistochemical assay based on monoclonal antiestrophilin antibodies has been used to localize estrogen receptor (ER) in frozen sections of normal human endometrial, myometrial and cervical tissues from menstruating, hormonally treated, pregnant and postmenopausal women. Specific staining was confined to the cellular nuclei. In proliferative phase endometrium, postmenopausal emdometrium, and endometrium from patients treated with hormone ERs were easily detected in most glandular and stromal cells. After ovulation and in early pregnancy a quick and distinct decrease of ER expression was noted. This was especially the case with the more superficial layers of endometrium (endometrium functionalis), the majority of whose cells had either weak localization of ER or none at all. In the endometrium basalis, however, the reduction of ER localization turned out to be more moderate. More then half of the epithelial and stromal cells displayed nuclear staining, partly strong. The myometrium of the corpus uteri showed a similar ER localization and dependence on hormonal stage when compared with the endometrium functionalis. The endocervical mucosa displayed a high degree of ER expression in the proliferative phase, in postmenopausal women and in women who had been treated with hormones. Unlike the endometrium and myometrium, the endocervical glands underwent minimal changes in nuclear ER content during the menstrual cycle. Although the endocervical stroma showed cyclic alterations in ER levels, their reduction after ovulation was less marked than in the corresponding endometria. In cervical squamous epithelium ER localization was predominantly confined to the basal layers. In the course of cellular maturation, specific nuclear staining vanished. In the proliferative phase, after the menopause and in early pregnancy, the basal, parabasal and intermediate cells were specifically stained. In the postovulatory phase, However, nuclear staining was confined to the basal and parabasal cells. Hormonally treated squamous epithelia almost completely lacked nuclear ER localization.

Oestrogen receptor in glands and stroma of normal and neoplastic human endometrium: a combined biochemical, immunohistochemical, and morphometric study

Cryostat sections of unfixed human endometrial tissue from normal, hyperplastic, and carcinomatous endometrium were assayed for oestrogen receptor content using a radiolabelled oestradiol binding assay with isoelectric focusing to separate receptor proteins. The proportions of myometrium, stroma, and glandular tissue were estimated in adjacent sections by point counting. Further cryostat sections were stained for oestrogen receptor immunohistochemically with a monoclonal antibody and the relative staining intensity of the various tissue components assessed. The area proportions and relative immunohistochemical staining intensity of each tissue component in the cryostat sections were then used to adjust the biochemical results and derive separate values of oestrogen receptor content in myometrium, glands, and stroma. The greatest difference in oestrogen receptor content through the menstrual cycle and between normal, hyperplastic, and malignant endometrium occurred in the glandular element.

The effect of estradiol-17 beta and actinomycin D on the release of PGF and PGE from separated cells of human endometrium

Estradiol-17 beta selectively stimulated the release of PGF from separated glandular but not stromal cells of human secretory endometrium (p less than 0.025) but had no effect on PGF release from either type of cells obtained from proliferative endometrium. PGE release was not affected by estradiol-17 beta. Actinomycin D did not antagonise the effect of estradiol-17 beta on PGF release from secretory, glandular cells. Basal release of PGF from these cells was stimulated by actinomycin D alone (100 ng/ml) (p less than 0.025) and PGE release stimulated in the presence of estradiol-17 beta. Actinomycin D had no effect on PGF or PGE release from proliferative endometrium. These findings suggest that estradiol-17 beta stimulates PGF release by a mechanism that does not affect PGE release and which is not dependent on the synthesis of new protein. The basal release of PGF and PGE by glandular cells of secretory endometrium in vitro is regulated by protein/proteins which reduce PG release.

Effects of dydrogesterone on the oestrogenized postmenopausal endometrium

Postmenopausal women receiving conjugated oestrogens 1.25 mg daily continuously were also given dydrogesterone either 5, 10 or 20 mg daily for the first 12 days of each calendar month. Endometrial tissue obtained on the sixth day of combined therapy in the third or subsequent treatment cycle was subjected to histological, ultrastructural and biochemical assessments. Dydrogesterone provoked secretory histological and ultrastructural changes within the endometrium in a dose-dependent manner. A daily dose of 5 mg produced sub-optimal responses but 10 and 20 mg daily produced effects similar to those observed in the secretory phase of the ovulatory cycle. Dydrogesterone 10 mg and 20 mg daily reduced epithelial DNA synthesis and nuclear oestradiol receptor levels to values within the secretory phase range. A dose-response relation was seen in the induction of oestradiol-17 beta and isocitrate dehydrogenase activities; hyperphysiological values were observed with 20 mg of dydrogesterone daily. This study has demonstrated that dydrogesterone exerts potent anti-oestrogenic and progestational effects on the human endometrium which are dose-related. The 10 and 20 mg doses induced responses equal to or greater than those observed in the secretory phase of the ovulatory cycle and both dosages can be recommended for use in combination with exogenous oestrogens in postmenopausal women: and they may also have a role in the management of anovulatory dysfunctional uterine bleeding.

Immunological probes for oestradiol receptors in human breast tumours

Monoclonal antibodies have been prepared against a soluble oestradiol receptor (REC) preparation partially purified from human myometrium by oestradiol affinity chromatography. The antibodies were detected by their ability to immunoprecipitate receptor bound [125I] oestradiol. One of the antibodies (D5) has been studied in detail. It will only precipitate REC after activation by salt, heat, low pH or KCNS and will not react with nuclear RE. It will not react with androgen, progesterone or glucocorticoid receptors nor with sex hormone binding globulin; it will only combine with REC from human sources. D5 recognizes a cytoplasmic 29 kdalton protein (p29) that can be separated from both type I and II soluble oestradiol binding proteins. p29 can react with activated REC and is qualitatively and quantitatively related to REC. IRMA and histochemical methods have been developed for quantitating p29 and relating its amount to receptors in human breast tumours. With both methods, highly significant (P less than 0.001) correlations with REC but not RP have been obtained. Both methods indicate that many REC-RP+ tumours contain p29. The histochemical method detects marked cellular heterogeneity in some tumours. The function of p29 is not known. It is an REC-related antigen that may be a previously undetected component of the oestradiol receptor machinery.

High-performance chromatofocusing and size-exclusion chromatography: separation of human uterine estrogen-binding proteins

We have employed high-performance chromatofocusing (HPCF) and high-performance size exclusion chromatography (HPSEC) to separate and identify radiolabelled estrogen binding proteins present in human uterine cytosol. Results obtained using these high-performance methods are compared to results of similar analyses by conventional isoelectric focusing procedures and open-column size exclusion chromatography. By HPCF, descending pH gradients (pH 8-4) allow us to discern four to five estrogen binding proteins with elution pH values typically between pH 4.5 and 7.2. However, when using HPCF, significant quantities of estrogen binding proteins are rarely detected between pH 7.2 and 8.0. This observation has been confirmed by open-column chromatofocusing of these proteins on Polybuffer Exchanger 94. In contrast, preparative isoelectric focusing by electrophoresis in polyampholytes reveals substantial quantities of estrogen binding activity eluted between pH 7.5 and 8.0. Several possible explanations for this disparity are discussed. Apparent differences are also observed when the size heterogeneity of estrogen binding proteins is analyzed simultaneously by size exclusion chromatography in open-column (Sephacryl S-300) and high-performance (TSK-3000SW) modes. HPSEC of these estrogen binding proteins on TSK-3000SW columns demonstrates a predominant 80-85 A species, whereas size exclusion chromatography on conventional Sephacryl S-300 columns reveals two to three distinct regions of estrogen binding proteins with Stokes radii of ca. 85, 60 and 30 A (major species). The larger form of receptor, whether a non-specific aggregate or a multisubunit complex, is stable in unfractionated cytosol and becomes more labile only during size exclusion chromatography.

Human endometrium in cell culture: a new method for culturing human endometrium as separate epithelial and stromal components

The present study describes a simple method for culturing human endometrium as separate epithelial and stromal components. Fifty-two samples of normal human endometrium have been initiated in tissue culture: endometrium from both the proliferative and luteal phases of the menstrual cycle showed satisfactory growth in vitro with a success rate of about 94%. Epithelial cultures remained viable for 60 days, while from stromal cells it was possible to establish cell lines. Both cell types possessed estrogen receptors. Epithelial cells showed no clear estrogen or progesterone response. Our observations suggest that this simple method for culturing human endometrium may serve as a tool in further investigations.

Dose dependent effects of oral progesterone on the oestrogenised postmenopausal endometrium

Oral progesterone 100, 200, or 300 mg daily was given for the first 10 days of each calendar month to postmenopausal women also receiving conjugated oestrogens 1.25 mg daily continuously. Endometrial biopsy specimens were taken on the sixth day of the third or subsequent cycle of combined treatment for histological, ultrastructural, and biochemical evaluation. Secretory histological changes were induced within the endometrium in a dose dependent manner, as were progesterone sensitive ultrastructural features such as nucleolar channel systems, giant mitochondria, and subnuclear accumulations of glycogen. Dose response relations were also observed for suppression of DNA synthesis and nuclear oestrogen receptor, and for induction of the activities of oestradiol and isocitric dehydrogenases. Progesterone administered by mouth clearly provokes an end organ response within the endometrium. Suboptimal effects were observed with the lower doses but progesterone 300 mg daily achieved responses approaching and within the physiological range. This dose may therefore be effective as an alternative to synthetic progestogens for therapeutic purposes.

Subcellular distribution of androgens and oestrogens in target tissue

To study the endogenous concentration of androgens and oestrogens in target tissue, three different methods have been used: (a) measurement of concentration gradient across mammary tumours, (b) long-term infusion of subphysiological amounts of labelled oestrogens and measurement of tissue-plasma gradients in human uterine tissue and (c) measurement of endogenous concentrations in mammary and uterine tissues. In addition to the tissue-plasma gradient, the subcellular distribution was also measured. An improved method is presented for processing the tissue and for the quantitative extraction of steroid hormones from cytosol and nuclear fraction. The data obtained show clearly that steroid hormones have a tissue-plasma gradient that varies from tissue to tissue and from one hormone to another. As steroid hormones exert their influence intracellularly at the site of receptor binding, our findings may have major consequences for the study of hormone-related cancers of the breast and of the uterus.

Actions of progestins on the morphology and biochemistry of the endometrium of postmenopausal women receiving low-dose estrogen therapy

Endometrial biopsies were obtained from postmenopausal women receiving 0.625 mg Premarin daily and either 2.5 or 5 mg norethindrone daily or 150 or 500 microgram dl-norgestrel daily for 10 days each month. Sample were taken during the estrogen-only phase of treatment and on the sixth day of combined estrogen/progestin administration. Progestin exposure caused marked morphologic and biochemical changes as well as features comparable with the premenopausal luteal phase. Thus, progestins oppose the stimulation of premarin to the postmenopausal endometrium. However, the currently recommended dosage of norethindrone and dl-norgestrel greatly exceed those necessary to suppress endometrial proliferation effectively. The recommended daily dosage may be lowered without losing protective effect. This reduction will probably minimize the risk of dose-dependent progestin side effects.