Estradiol binding and metabolism in human endometrial hyperplasia and adenocarcinoma

Key Considerations for Studying the Effects of High-Fat Diet on the Nulligravid Mouse Endometrium

The obesity epidemic continues to increase, with half of US women predicted to be obese by 2030. Women with obesity are at increased risk for not only cardiovascular and liver disease, but also reproductive disorders. Although mouse models are useful in studying the effects of obesity, there is inconsistency in obesity-induction methods, diet composition, and mouse strains, and studies using female mice are limited. In this study, we sought to compare the effects of a 45% high-fat diet (HFD) versus a 60% HFD on the uterine estrous cycle of nulligravid C57BL/6J mice. For 22 weeks, we placed a total of 20 mice on either a 60% HFD, 45% HFD, or each HFD-matched control diet (CD). Both HFDs produced significant weight gain, with 60% HFD and 45% HFD gaining significant weight after 2 weeks and 15 weeks, respectively. Additionally, both HFDs led to glucose intolerance, fatty liver, and adipocyte hypertrophy. Mice fed 60% HFD displayed hyperphagia in the first 12 weeks of HFD treatment. Moreover, 60% HFD-treated mice had a longer estrous cycle length and an increased percentage of estrus stage samplings compared to CD-treated mice. Estrous cycle stage-controlled 60% HFD-treated mice displayed an increased estrogen-to-progesterone ratio and decreased ovarian corpora lutea compared to CD-treated mice, which may underlie the observed estrous cycle differences. There was no significant difference between diets regarding endometrial morphology or the percent of endometrial CD45+ immune cells. Our results indicate that consideration is needed when selecting a HFD-induced obesity mouse model for research involving female reproductive health.

Decreased suppression of interleukin-6 after treatment with medroxyprogesterone acetate and danazol in endometrial stromal cells of women with adenomyosis

OBJECTIVE

To examine changes in local cytokine production in the eutopic endometrium of adenomyosis after treatment with medroxyprogesterone acetate (MPA) and danazol.

DESIGN

Prospective cohort study.

SETTING

Tertiary university hospital.

PATIENT(S)

Twenty-four women with adenomyosis (study group) and 22 women without adenomyosis (control group).

INTERVENTION(S)

Eutopic endometrium was separated into single endometrial stromal cells (ESCs), and was cultured in vitro alone, with MPA (10(-7) M), or with danazol (10(-7) M) for 8 days.

MAIN OUTCOME MEASURE(S)

Messenger RNA expression of interleukin (IL)-6, IL-8, and tumor necrosis factor-alpha in ESCs, and their concentrations in the supernatants of ESCs.

RESULT(S)

A significant decrease of IL-6 concentration in the supernatant, measured by ELISA, was found with time of ESCs cultured with MPA and danazol in the control group, but not in adenomyosis. The IL-6 mRNA in ESCs determined by real-time quantitative polymerase chain, as well as its concentration in the supernatant, was much higher in adenomyosis than that in the control group after treatment with MPA and danazol for 8 days.

CONCLUSION(S)

Medroxyprogesterone acetate and danazol appeared to have a decreased effect on the suppression of IL-6 liberated by ESCs in adenomyosis. This aberrant secretion of IL-6 might play a role in the formation of ectopic endometrial implants in adenomyosis.

Endometrium in PCOS: Implantation and predisposition to endocrine CA

Polycystic ovarian syndrome (PCOS) is a common endocrinopathy characterized by oligo/anovulatiaon and elevated circulating androgens or evidence of hyperandrogenism after all known potential causes have been excluded. In addition, insulin resistance and accompanying hyperinsulinemia commonly occur in women with PCOS. There is increasing evidence that the endocrinologic and metabolic abnormalities in PCOS may have complex effects on the endometrium, contributing to the infertility and endometrial disorders observed in women with this syndrome. Androgen receptors and steroid receptor co-activators are over-expressed in the endometrium of women with PCOS. Also, biomarkers of endometrial receptivity to embryonic implantation-such as alpha(v)beta3-integrin and glycodelin-are decreased, and epithelial expression of estrogen receptor alpha (ERalpha) abnormally persists in the window of implantation in endometrium in women with PCOS. In addition to being responsive to the steroid hormones estradiol, progesterone, and androgens, the endometrium is also a target for insulin, the receptor for which is cyclically regulated in normo-ovulatory women. In vitro, insulin inhibits the normal process of endometrial stromal differentiation (decidualization). In addition, insulin-like growth factors (IGFs) and their binding proteins are regulated in and act on endometrial cellular constituents, and hyperinsulinemia down-regulates hepatic IGFBP-1, resulting in elevated free IGF-I in the circulation. Thus, elevated estrogen (without the opposing effects of progesterone in the absence of ovulation), hyperinsulinemia, elevated free IGF-I and androgens, and obesity all likely contribute to endometrial dysfunction, infertility, increased miscarriage rate, endometrial hyperplasia, and endometrial cancer common in women with PCOS. The potential mechanisms underlying these disorders, specifically in women with PCOS, are complex and await additional transdisciplinary research for their complete elucidation.

Estradiol−Adenosine Hybrid Compounds Designed to Inhibit Type 1 17β-Hydroxysteroid Dehydrogenase

The steroidogenic enzyme type 1 17beta-hydroxysteroid dehydrogenase (17beta-HSD) is involved in the synthesis of estradiol (E(2)), a hormone well-known to stimulate the growth of estrogen-sensitive tumors. To obtain compounds able to control E(2) formation, two moieties were linked with a methylene side chain: an adenosine moiety for interacting with the cofactor-binding site and an E(2) moiety for interacting with the substrate-binding site. When tested as inhibitors of type 1 17beta-HSD, the hybrid compounds inhibited the reductive activity (E(1) into E(2)) with IC(50) values ranging from 52 to 1,000 nM. The optimal side-chain length was determined to be eight methylene groups for a 16 beta-orientation. The presence of two components (E(2) and adenosine) is essential for good inhibition, since 16 beta-nonyl-E(2) and 5-nonanoyl-O-adenosine, two compounds having only one of the components, did not inhibit the enzyme. Moreover, the 3D-structure analysis of EM-1,745 complexed with type 1 17beta-HSD showed key interactions with both substrate- and cofactor-binding sites.

Hormonal regulation of implantation

Implantation is a complex process that requires synchronization between the embryo and a receptive endometrium. Hormones, such as the female sex steroids, prostaglandins, and peptide hormones, regulate the cellular and molecular mediators of endometrial receptivity, which include pinopodes, cell adhesion molecules, cytokines, homeobox genes, and growth factors. These mediators can be altered, despite the presence of normal hormone levels and endometrial histology; this limits the usefulness of the luteal phase endometrial biopsy. Therefore, analysis of markers of endometrial receptivity may predict successful implantation better. Elevated androgen and estrogen levels, as seen with polycystic ovary syndrome and controlled ovarian hyperstimulation, respectively, also can have detrimental effects on the endometrium, and therefore, implantation.

A 6beta-(thiaheptanamide) derivative of estradiol as inhibitor of 17beta-hydroxysteroid dehydrogenase type 1

In an effort to develop potent agents for reducing the levels of the active estrogen, estradiol, we developed a new category of 17beta-hydroxysteroid dehydrogenase (17beta-HSD) type 1 inhibitors. The compounds described possess a butyl methyl alkylamide side chain linked to the C6 position of estradiol by a thioether. With a series of epimeric mixtures, an optimal side-chain length of five methylene groups (between the amide group and steroid part) was first determined. Thereafter, both C6 epimers of optimized mixture were obtained after high-pressure liquid chromatography separation. 1H and 13C NMR experiments were performed to confirm the stereochemistry of each epimer. The 6beta-orientation of the side-chain was found to be crucial for enzymatic inhibition. Indeed, for the optimized side-chain length, the compound with a beta-orientation (5: N-butyl,N-methyl 7-(3',17'beta-dihydroxy-1',3',5'( 10')-estratriene-6'beta-yl)-7-thiaheptanamide) was 70-fold more potent than the 6alpha-analog. Compound 5 did not inactivate 17beta-HSD type 1, suggesting a reversible inhibitor. In addition, it was found to be a more potent inhibitor than the substrate estrone itself or a panel of three known inhibitors.

17 beta-Hydroxysteroid dehydrogenase type 2: chromosomal assignment and progestin regulation of gene expression in human endometrium

The cDNAs for two separate human 17 beta-hydroxysteroid dehydrogenases (17 beta-HSD) have been isolated and sequenced. The well-studied human placental cytosolic 17 beta-HSD (also referred to as estradiol dehydrogenase) preferentially catalyzes the reduction of estrone to estradiol-17 beta and the reduction of the C-20-ketone of progesterone to 20 alpha-dihydroprogesterone. This isoform of the enzyme has been referred to as 17 beta-HSD type 1 and localized to chromosome 17. A second 17 beta-HSD isoform (referred to as type 2) is localized in the endoplasmic reticulum of human trophoblast and is characterized by the preferential oxidation of the C-17 beta-hydroxyl group of C18- and C19-steroids and the C-20 alpha-hydroxyl group of 20 alpha-dihydroprogesterone. In this study, we determined the chromosomal localization of human 17 beta-HSD type 2, the expression of this gene in human endometrium, and the tissue distribution of the mRNA. We found that the human 17 beta-HSD type 2 gene is localized on chromosome 16, 16q24. 17 beta-HSD type 2 mRNA (approximately 1.5 kb) was identified in human endometrial tissues by Northern analysis of total RNA (10 micrograms). The highest levels of 17 beta-HSD type 2 mRNA were found in endometrial tissues obtained during the mid- to late secretory phase of the ovarian cycle (i.e., during the time of high plasma levels of progesterone). 17 beta-HSD type 2 mRNA levels were much greater in glandular epithelium than in the stromal cells isolated from secretory phase endometrium. The levels of 17 beta-HSD type 2 mRNA in secretory phase endometrium were approximately one-tenth that in villous trophoblast tissue from human placenta. We did not detect 17 beta-HSD type 1 mRNA in endometrial tissue by Northern analysis of total (10 micrograms) RNA. These findings are consistent with the view that the progestin-regulated 17 beta-HSD of the glandular epithelium of the human endometrium is primarily, if not exclusively, the product of the 17 beta-HSD type 2 gene. 17 beta-HSD type 2 mRNA was present in human placenta, liver, and small intestine; much smaller amounts, barely detectable by Northern analysis of poly(A)+ RNA, were present in prostate, kidney, pancreas, and colon, but not in heart, brain, skeletal muscle, spleen, thymus, ovary, or testis.

The effect of dietary fat and fiber on serum estrogen concentrations in premenopausal women under controlled dietary conditions

The effect of dietary fiber and fat on serum sex hormones was studied in premenopausal women. After an initial control period during which the diet was high in fat (40% of calories as fat) and low in fiber (12 g/day), the amounts of fat and fiber were varied in the setting of a metabolic kitchen and carefully monitored meals. Forty-eight women completed 58 protocols. When the diet was changed to low-fat (20-25% calories as fat) and high fiber (40 g/day), there were significant decreases in serum concentrations of estrone, estrone sulfate, testosterone, androstenedione, and sex hormone binding globulin (SHBG) and near significant decreases in estradiol and free estradiol. When independent effects were examined, high fiber alone caused a decrease in estradiol and SHBG, whereas fat and fiber caused the observed decrease in estrone sulfate. Dietary fat independently influenced the serum concentration of androstenedione. Increased dietary fiber caused a lengthening of the menstrual cycle by 0.72 day and a lengthening of the follicular phase by 0.85 day.

Metabolism of the oral contraceptive steroids ethynylestradiol, norgestimate and 3-ketodesogestrel by a human endometrial cancer cell line (HEC-1A) and endometrial tissue in vitro

Human endometrial cancer cells and human endometrial tissue have been extensively used to study steroid hormone action and metabolism. The natural estrogens estradial (E2) and estrone (E1) are known to be metabolized by both cells and tissue with the interconversion of the two steroids and the formation of sulphate conjugates. The aim of the present work was to see if the commonly used oral contraceptive steroids ethynylestradiol (EE2), norgestimate (Ngmate) and 3-ketodesogestrel (3-KDG) were metabolized by a human endometrial cancer cell line (HEC-1A) and human endometrial tissue in vitro. Metabolites were analysed by on-line radiometric HPLC. Endometrial tissue was obtained from women undergoing dilation and curettage or hysterectomy operations. In preliminary studies with endogenous estrogens, HEC-1A cells were able to interconvert E1 and E2; the equilibrium favouring the formation of E2. Normal endometrial tissue extensively converted E2 to E1, tumour tissue appeared to catalyse this reaction much less avidly. In addition sulphate conjugates were formed by normal tissue from some patients. Cell line and endometrial tissue was able to hydrolyse estrone 3-sulphate. With EE2 as substrate there was no evidence of phase I metabolism by cell line or tissue. However, conversion to the presumed 3-sulphate conjugate was observed following incubation with normal tissue from some women. Deacetylation of the progestogen Ngmate to norgestrel oxime (NgOx) was complete within 24 h. There was also some loss of the oxime moiety to give norgestrel (Ng) following incubation with HEC-1A cells. Metabolism of Ngmate was also complete within 24 h following incubation with endometrial tissue. There were both qualitative and quantitative differences in metabolite formation between tissue obtained from different women. In contrast, 3-KDG was relatively resistant to metabolism by cell line and tissue. The major metabolite formed by HEC-1A cells accounted for only 3.3 +/- 0.4% of total added radiolabelled steroid and co-chromatographed with 3 alpha-hydroxydesogestrel. Smaller amounts of other radiometabolites were formed. No phase I metabolites of 3-KDG were formed by normal endometrial tissue, however small amounts of radiometabolites appeared to be formed by malignant tissue. These studies have provided evidence to suggest that the oral contraceptives EE2, Ngmate and 3-KDG are metabolized in the human endometrium. Knowledge of the metabolism of these in target tissues such as the endometrium may be pertinent considering the possibility that metabolites may exert specific effects.

Immunological measurement of human 17 beta-hydroxysteroid dehydrogenase

Human placental 17 beta-hydroxysteroid dehydrogenase (17-HSD) was purified to apparent homogeneity using ammonium sulfate precipitation and chromatography on Red-Agarose and DEAE-Sepharose columns. Electrophoresis on polyacrylamide gels under denaturing conditions and using silver staining showed a single protein with an apparent molecular weight of 37,800. Antibodies to the purified protein were raised in rabbits and were found by immunoblotting to be specific to 17-HSD. A sensitive radioimmunoassay was established using 125I-labeled 17-HSD as a tracer, an appropriate dilution of the antibody, and a kaolin-coupled double antibody for separating the antibody-bound and free fractions. The detection limit of the assay was approximately 150 pg/tube (1.5 micrograms/l). The cytosol fraction (105,000 g) of term placental tissue contained approximately 0.7 mg of 17-HSD per gram of protein, and the concentrations of 17-HSD measured by immunoassay and enzymatic activity proved to be strictly parallel in different partly purified placental preparations. The supernatants from centrifugations of human endometrial homogenates at 800 g and 105,000 g (after detergent treatment) displayed cross-reactivity with the antibody. The mean concentration of the cross-reacting substance in the radioimmunoassay was 14.1 micrograms/g protein (range 2-62.3) in specimens taken on different days in the cycle. These concentrations showed a significant correlation with the 17-HSD activities measured in the endometrial specimens (r = 0.722, P less than 0.001, n = 21). Mean concentrations of substance were 8.3 micrograms/g protein in endometrial specimens taken during the follicular phase (days 4-12, n = 8) and 22.9 micrograms/g protein during the luteal phase (days 16-22, n = 6) were obtained using the radioimmunoassay. There was excellent parallelism between the competition curves for [125I]iodo-17-HSD with purified 17-HSD standards and placental and endometrial homogenate dilutions. These data strongly suggest that the substance measured in the endometrial specimens was 17-HSD.

Uterine estrogen sulfatase activity. Influence of steroid hormones and adenine nucleotides

Steroid sulfatase enzymes participate greatly in reproductive events. To date, estrogen sulfatase seems to have a regulatory role in the control of free estrogen levels in target tissues. The present study evaluates the participation of some adenine nucleotides in estrogen sulfatase kinetics. Using ADP, ATP, NAD and the combination of ADP + NAD or ATP + NAD it was found that adding either of the combined cofactors, the enzymatic activity increased more than 2.0 times. In ovariectomized rats, the corresponding mean enzyme activity was found to be higher than in intact rats. It was also found, in ovariectomized rats treated with ovarian hormones, an inhibition that was higher with estradiol-17 beta than with progesterone treatment. This data suggests that the estrogen sulfatase, being a hormone-dependent enzyme, participates in a new control mechanism of estrogen levels in presence of some cofactors and free steroids.

Estrone sulfatase activity in human uterine leiomyoma

Human uterine leiomyoma is a benign tumor and its development is closely related to estrogen. In this study, estrone sulfatase (E1SF) activity and concentrations of estrone (E1) and estrone sulfate (E1S) were measured in endometrial, leiomyoma, and myometrial tissues of the same human uterus (n = 11) with a leiomyoma. E1SF activity in endometrial tissue overlying a leiomyoma was 2.62 +/- 0.29 nmole/hr/mg protein (mean +/- SD), this activity being significantly higher (P less than 0.01) compared with that in normal endometrial tissue (2.0 +/- 0.24 nmole/hr/mg protein). E1SF activity in normal endometrial tissue was significantly higher (P less than 0.001) compared with that in leiomyoma tissue (0.49 +/- 0.82 nmole/hr/mg protein) or myometrial tissue (0.76 +/- 0.10 nmole/hr/mg protein). We also found a significant difference (P less than 0.05) in E1SF activity between leiomyoma tissue and myometrial tissue. On the other hand, the E1 concentration in endometrial tissue overlying a leiomyoma (10.9 +/- 8.9 pg/mg protein) proved to be higher than that in endometrial tissue overlying normal myometrium (1.23 +/- 1.97 pg/mg protein). E1S concentrations in these tissues, however, were 631 +/- 339 and 902 +/- 482 pg/mg protein, respectively, these values showing a trend opposite that of the E1 concentration data. Thus, these results suggest that high E1SF activity and high E1 concentration in the endometrium overlying a leiomyoma may be related to estrogen supply to a uterine leiomyoma node.

Characterization of two mRNA species encoding human estradiol 17 beta-dehydrogenase and assignment of the gene to chromosome 17

Using two 33-mer synthetic oligonucleotides derived from the amino acid sequence of the catalytic site of estradiol 17 beta-dehydrogenase (E2DH) and polyclonal antibodies raised against the enzyme purified from human placenta, clones were isolated from a lambda gt11 human placental cDNA library. A 327-amino acid sequence was deduced from cDNA sequencing. Two mRNA species have been identified in poly(A)+ RNA from human placenta, a major species migrating at 1.3 kb while a minor one is found at approx. 2.2 kb. Primer extension and S1 nuclease analysis indicate that the major mRNA species starts 9-10 nucleotides while the minor mRNA starts 971 nucleotides upstream from the ATG initiating codon, respectively. Sequence analysis of the longest cDNA clone (2092 bp) shows that it possesses identical coding and non-coding sequences in the regions of overlap with the shorter cDNA clones. The 32P-labeled 5' non-coding fragment hybridizes only to the 2.2 kb band, thus providing evidence for the existence of two distinct mRNA species which differ in their 5' noncoding regions. Using hp E2DH-36 cDNA as a probe for in situ hybridization of translocated chromosomes, the human E2DH gene was localized to the q11-q12 region of chromosome 17.

Steroid hormone receptors in carcinoma of the cervix

To correlate the presence of specific steroid receptors with certain characteristics of cervical carcinoma, cytosol estrogen receptors (ERc) were measured in 70 cases of cervical carcinoma, and progesterone receptors (PRc) were measured in 56 of these cases; ERc and PRc were also measured in 17 normal cervices. Measurements were made using a dextran-coated charcoal technique involving a seven-point Scatchard plot analysis. In carcinoma of the cervix significant numbers of ERc (greater than 3 fmol/mg protein) were found in 41% of the cases, and of PRc (greater than 3 fmol/mg protein) in 30%; only 28% of the 56 cases contained both ERc and PRc. In the normal cervices, 59% contained significant levels of ERc and 41% significant levels of PRc. No correlation was found between ERc and PRc and menopausal status of the patient, stage, cell type, or histologic grade of the tumor. A weak (P = 0.063) correlation between the presence of PRc and length of survival was also found, but there was no correlation between ERc and survival. Unlike the situation for breast cancer, measurement of ERc and PRc appears to add little of value to the clinical management of cervical carcinoma.

Postmenopausal bleeding: etiology, evaluation, and management

Postmenopausal bleeding can be an alarming symptom for both the patient and the physician because, although in a majority of these cases no pathology is present, the risk of malignancy must be considered. It is important for the physician to fully understand the pathophysiology, differential diagnosis, and the methods of evaluating and treating this disorder in order to ensure the health and comfort of the patient.

Estrone sulfatase activity in normal and abnormal endometrium

We investigated the activity of estrone sulfatase in normal and pathological endometrium. In normal endometrium, the estrone sulfatase activity [pmol E1 X min-1 X (mg prot)-1] was 23.13 +/- 8.44 (mean +/- SD). An increase (p less than 0.01) of estrone sulfatase activity (62.81 +/- 21.97) was noted in mild endometrial hyperplasia. In focal hyperplasia (when the measurements were performed in the normal endometrial biopsies) such an increase was not noted (19.10 +/- 5.33). Estrone sulfatase activities of moderate hyperplasia (25.30 +/- 11.40) and endometrial neoplasia (30.30 +/- 9.57) were in the same range as in normal endometrium. Treatment with progestagen simultaneously reduced hyperplasia and estrone sulfatase activity. But when morphologically abnormal endometrium persisted after treatment, estrone sulfatase activity remained increased. The increase of estrone sulfatase activity appeared to be specific to mild endometrial hyperplasia. The role of estrone sulfatase in the pathogenesis of endometrial hyperplasia is discussed.

Estrone and dehydroepiandrosterone sulfatase activities in guinea-pig uterus and liver: estrogenic effect of estrone sulfate

Estrone and dehydroepiandrosterone (DHA) sulfatase activities were studied in the uterus and liver of female guinea-pigs (albino variety). The two activities were found in particulates, with the highest specific activity in microsomes. The effects of pH, buffers, temperature and the non-competitive inhibition of DHA sulfate on estrone sulfatase provided arguments for the existence of two distinct sulfatases. However, acrylamide gel electrophoresis of the solubilized microsome sulfatases gave a single peak for the two activities. In the uterus, the apparent Km of estrone and DHA sulfatases were 26.4 and 15.6 microM. Solubilized microsomal estrone sulfatase was inhibited by unconjugated steroids. The apparent Km of estrone sulfatase in liver was 10.7 microM. Estrone and DHA sulfatase activities were consistently lower in liver than in uterus and no DHA sulfatase activity was detected in fetal liver. In the uterus, the same sulfatase activities were found in female fetuses, castrated or mature females. Estrone sulfatase was significantly increased in the uterus of pregnant females (60-65 days gestation). Estrone sulfate was injected in vivo into mature castrated females. A significant increase in uterine weight and in uterine progesterone receptors was observed. The cytosol progesterone receptors were characterized by their Kd (1.40 nM) and by sucrose density gradient. It is concluded that the variations of estrone sulfatase activity in target tissues like the uterus may control the intracellular levels of biologically active estrogens.

Prevention by progesterone of cervicovaginal lesions in neonatally estrogenized BALB/c mice

Instillation of progesterone into the vaginal lumen of BALB/c mice treated neonatally with 25 micrograms 17 beta-estradiol resulted in a significant decrease in vaginal concretions (P less than 0.025), vaginal cornification (P less than 0.025) and vaginal lesions (P less than 0.05).

Peripheral aromatization as a risk factor for breast and endometrial cancer in postmenopausal women: a review

In menopause, estrogens are produced almost exclusively through peripheral aromatization of androgens, especially androstenedione. Obesity increases the production rate of estrogens by means of the same mechanism. In postmenopause, plasma levels of SHBG diminish significantly. Obesity even further decreases the levels of SHBG, thus increasing "free" E2 available to target tissues. The increase in circulating estrogenic activity in menopause, whether as a result of obesity or of ingestion of estrogens, implies a risk factor for endometrial and breast cancer not only because of the permissive and stimulating effects of estrogens but also due to the special circumstance that they may act on target tissues in the almost absolute absence of the "protecting effect" of progesterone. The modifications performed by obesity on the values of SHBG and circulating estrogens are reversible, since they tend to normalize with weight loss.

Role of estrogens and progesterone in the etiology and prevention of endometrial cancer: review

Our present knowledge of the role of sex steroids in the development as well as the prevention of endometrial cancer is reviewed. Factors which increase the exposure of the uterus to unopposed estrogens, either exogenous or endogenous, are associated with increased risk of endometrial adenocarcinoma. However, there is increasing evidence that progestogens can reverse endometrial hyperplasia and protect against the development of endometrial cancer. The mechanisms to explain the antiestrogenic effects of progestogens include changes in enzyme activity and steroid receptors in endometrial tissue. Postmenopausal women treated with combined estrogen and progestogen have the lowest incidence of endometrial carcinoma. Oral contraceptives containing both estrogen and progestogen in each tablet are protective against adenocarcinoma of the endometrium, while the sequential oral contraceptive pills afforded less protection. The risks and benefits of these hormone therapies are discussed in relation to the etiology and prevention of endometrial cancer.

Estrogen and progesterone receptors in ovarian neoplasms

The cytoplasmic receptors for 17 beta-estradiol (ER) and progesterone (PR) were measured in 39 malignant and 15 benign ovarian neoplasms. All eight endometroid carcinomas had positive ER sites, one-half contained PR. The number of ER binding sites decreased as tumor grade increased. Conversely, none of the 11 mucinous tumors contained either ER or PR receptors. One-half of the well-differentiated serous tumors had ER (57 +/- 23 fmole/mg protein) while none of the poorly differentiated tumors had measurable binding. In serous carcinomas, PR was only detected in well-differentiated lesions (447 +/- 240 fmole/mg protein). Only one of 15 benign neoplasms contained ER and PR receptors. Correlation of tumor grade and type may help to plan hormonal therapies in advanced ovarian malignancies.

Intra-tumoural variation of oestrogen receptor status in endometrial cancer

Soluble and nuclear oestrogen receptor status was determined in both the central and peripheral portions of tumour for 37 cases of adenocarcinoma of the endometrium. Of these, 29 had functional receptor in the peripheral biopsy, but only 19 retained functional receptor in the centre. Six of the 10 patients whose tumours showed this difference came from the group of 12 patients who were immediately post-menopausal (4.50 +/- 1.45 y post-menopausal age). Receptor status was not related to tumour classification into histological grades I and II. However, receptor-negative central biopsies were significantly more likely (P less than 0.05) to be Grade III. Early relapse was also related to a receptor-negative central biopsy.

Estrogen and progesterone receptor sites in malignancies of the uterine cervix, vagina, and vulva

Cytoplasmic receptors for 17 beta-estradiol (ER) and progesterone (PR) were measured in uterine cervical, vaginal, and vulvar carcinomas by the dextran-coated charcoal (DCC) technique. Tissues from 30 patients with cervical carcinoma were examined. Thirteen percent (2 of 16) of well-differentiated squamous carcinomas had positive ER, and 19% (3 of 19) had positive PR. None of the three patients with moderately well-differentiated disease have positive ER or PR, while two of five patients with poorly differentiated lesions contained measurable ER and PR. In contrast, all four of the well-differentiated adenocarcinomas of the cervix had detectable ER, and three of four for PR. Neither of the two patients with poorly differentiated adenocarcinoma had either ER or PR. None of the five vulvar and seven vaginal epidermoid carcinomas studied had ER or PR activity. Hormonal therapies may be useful in the treatment of adenocarcinoma of the cervix.

Estrone sulfatase activity in guinea pig tissues

Estrone sulfatase activity is widespread in guinea pig tissues. Whole homogenates of adult testis, uterus, lung, adrenal, amnion, ovary, chorion, small intestine, placenta, spleen, kidney and liver exhibit approximately descending order of specific activity. Certain properties, including pH requirement, lack of inhibition by inorganic sulfate and magnitude of estimated Km values, are similar to that for arylsulfatase C of rat liver. Of the subcellular fractions prepared from guinea pig tissues, microsomes exhibit the highest specific activity although considerable enzyme activity remains associated with large cellular fragments sedimenting at 750 g. The sulfatase activity is readily inhibited by inorganic phosphate even when substrate concentration satisfied zero order kinetics. Rat liver arylsulfatase C is not inhibited under these conditions. Sensitivity of the guinea pig enzyme activity to inhibition by a variety of steroids and related compounds, is markedly less than for rat liver. Diethylstilbestrol(DES) strongly inhibits the rat liver enzyme but has little effect on the guinea pig liver system. Guinea pig testicular activity is suppressed to a degree intermediate between these extremes by increasing DES concentration. In guinea pig lung, kidney, and possibly liver, elevated fetal enzyme activities decrease from neonatal to adult life. Testicular activity appears to follow the opposite trend. Uterine enzyme activity is not markedly affected by pregnancy.

Cytoplasmic progesterone and estradiol receptors in normal, hyperplastic, and carcinomatous endometria: therapeutic implications

This study was designed to determine whether the presence of progesterone receptors (PR) and/or estradiol receptors (ER) could be used to predict progestin responsiveness of recurrent or advanced endometrial cancers. We have demonstrated the presence of physicochemically similar cytoplasmic progesterone and estradiol receptors in normal, hyperplastic, and carcinomatous endometria. All normal endometria contained both PR and ER. Seventy-three percent of endometrial hyperplasias were PR(+) and 93% were ER(+). A decreasing concentration of progesterone receptor activity was observed with increasing tumor anaplasia [grade 1, 84% PR(+); grade 2, 55% PR(+); grade 3, 22% PR(+)] and in irradiated tumors. A statistically significant (p less than 0.001) relationship has been demonstrated between the presence of specific cytoplasmic PR and response to progestin therapy in recurrent or advanced endometrial adenocarcinomas. Thus, we conclude that a PR assay may be used to help select the most appropriate therapy for patients with recurrent or advanced endometrial adenocarcinoma.

Estradiol and progesterone receptors in estrogen-primed endometrium

Estradiol and progesterone receptor levels were measured in endometrial samples obtained from patients who were on different dosages of estradiol therapy and from women in the late proliferative phase of a normal menstrual cycle. Samples of blood were collected at the time of biopsy, and the levels of estradiol, estrone, progesterone, follicle stimulating hormone, and luteinizing hormone were measured in the serum. The patients were divided into five groups. The first group (controls) consisted of patients in their late proliferative phase. The patients in groups two, three, and five were receiving estradiol in various doses by pellet therapy, along with a cyclic progestogen each month. The women in the fourth group also had implantation of estradiol pellets but failed to take the progestogen as advised. In our series, the levels of cytoplasmic estradiol and progesterone receptors were markedly elevated in the no progestogen group compared to the controls. There was no significant difference in the levels of the receptors in the groups which took the progestogen as advised.

Plasma estrone sulfate levels in postmenopausal women

Estrone sulfate levels were measured in the plasma of 63 postmenopausal women. The assay method involved prior extraction of the free estrogens, enzyme hydrolysis of the estrone sulfate with sulfatase and radioimmunoassay of the estrone liberated. The plasma levels ranged from 37 to 320 pg/ml (expressed as free estrone) with a mean value of 178 +/- 79 pg/ml. As observed in premenopause, estrone sulfate is quantitatively the most important circulating estrogen in postmenopausal women.

A study of endocrine and metabolic variables in postmenopausal women with endometrial carcinoma

Although an underlying endocrine-metabolic disorder has been implicated as causally related to the development of endometrial carcinoma, data to support such an association are ambiguous and/or contradictory. In this prospective study of 16 consecutive nonobese postmenopausal women with endometrial carcinoma and 16 cancer-free postmenopausal women matched for age and weight, fasting values for growth hormone (GH), insulin, prolactin, follicle-stimulating hormone, luteinizing hormone, estrone (E1), and estradiol (E2) were measured on 3 consecutive days. Intravenous glucose tolerance, pituitary GH release in response to arginine infusion, hyperglycemia, and hypoglycemia, and insulin secretion in response to arginine infusion and to hyperglycemia were analyzed. Our data show that these endocrine-metabolic profiles were not significantly different between the cancer patients and control subjects, suggesting that the postmenopausal women with endometrial cancer who is not obese exhibits no accountable endocrine or metabolic disorders.

The effects of oestrogens and progestogens on the postmenopausal endometrium

Cyclical regimens of unopposed oestrogens are associated with the development of endometrial hyperplasia and the incidence of hyperplasia is dose-related. As no pattern of vaginal bleeding serves as a reliable indicator of underlying endometrial pathology and as hyperplasia can develop subsequent to the finding of a normal endometrium and at any time from 2 to 35 mth after the start of treatment, serial biopsies are required on every patient. Oral oestrone and oestradiol complexes both give rise in the plasma principally to oestrone and therefore the term "Hormone replacement therapy" is inappropriate. The incidence of hyperplasia during sequential oestrogen/progestogen therapy is greatly reduced and therefore progestogens are capable of protecting against the development of this condition. Sequential regimens can also reverse oestrogen-related hyperplasia to normal endometrium.

Estrogen metabolism in normal and neoplastic endometrium

Studies on normal endometrium at different phases of the menstrual cycle have shown that progesterone and synthetic progestins reduce the levels of estradiol receptors in the tissue and increase the activity of estradiol-17beta-dehydrogenase, an enzyme that converts estradiol to estrone. These effects may account for the antiestrogenic characteristics of the progestins. Similar effects were obtained in some postmenopausal patients with endometrial adenocarcinoma treated for two to 10 days with oral medroxyprogesterone acetate. These results point to the potential usefulness of a short-term, in vivo biochemical test which, combined with histologic observations, may identify patients who are likely to respond to treatment with progestins.