Effects of an antiprogesterone (RU486) on the hypothalamic-hypophyseal-ovarian-endometrial axis during the luteal phase of the menstrual cycle

Mifepristone Treatment in Pregnant Murine Model Induced Mammary Gland Dysplasia and Postpartum Hypogalactia

Mammary gland dysplasia and postpartum hypogalactia often occur in humans and in the livestock breeding industry. However, their underlying mechanisms are not clear yet. Mifepristone, which has a high affinity for progesterone (P4) and glucocorticoid receptors, was exploited here to induce the disorders of mammary gland development and lactation. Four strategies were devised for treating pregnant mice with mifepristone. In the first strategy, mice were administered 1.20 mg mifepristone/kg body weight (BW) on pregnancy day 4 (Pd4). In the second strategy, mifepristone was administered to mice twice, with 1.20 mg/kg BW on Pd4 and 0.40 mg/kg BW on Pd8. In the third strategy, mice were treated with a single dose of 0.40 mg mifepristone/kg BW on Pd8. In the fourth strategy, mice were administered 0.40 mg mifepristone/kg BW on Pd8 and 0.20 mg mifepristone/kg BW on Pd12. The results suggested that mifepristone administration at the dose of 1.20 mg/kg BW on Pd4 caused significant reduction in milk production on lactation day 1 (Ld1), Ld2, and Ld3, as assessed using a weigh-suckle-weigh assay. Mammary β-casein expression, milk yields, litter growth rates, gland structure, and serum concentrations of 17-β estrogen (E2), P4, prolactin (PRL), growth hormone (GH), corticosterone (CORT) and oxytocin (OT) as well as the receptors of these hormones were determined during pregnancy or lactation after performing the first (Pd4) strategy. The results demonstrated that mifepristone administration during early pregnancy decreased β-casein expression, milk yields and litter growth rates, induced fewer alveoli, enlarged alveolar lumina, and altered the levels of E2, P4, PRL, GH, CORT, and OT as well as the mRNA expression of these hormonal receptors during pregnancy or early lactation. The present study on pregnant mice treated with mifepristone offers an innovative murine model to study the mechanism underlying mammary gland dysplasia and postpartum hypogalactia.

Treatment of a Woman with Inoperable Meningioma Using Mifepristone for 26 Years

Meningioma treatment includes observation of its growth or surgery with or without associated radiotherapy. However, drug treatment can be used for tumors deemed inoperable because of their size and location. Due to the presence of progesterone receptors, the use of antiprogestin mifepristone is recommended. This study describes a case of inoperable meningioma treated with mifepristone for 26 years without interruption. The patient is a 45-year-old woman diagnosed with plaque meningioma, extending from the bottom of her right orbit, through the length of the small wing of the sphenoid, part of the large wing of the sphenoid, especially near the superior orbital fissure, and at the ceiling of the orbit. As this meningioma was considered inoperable, treatment with 200 mg oral mifepristone was administered uninterruptedly for 26 years. This treatment initially halted the growth of the meningioma and subsequently resulted in a small reduction of its volume; however, the meningioma has persisted until the last evaluation. After five years of mifepristone use, hydroxyurea was added for nine months but was discontinued due to anemia and leucopenia. In conclusion, mifepristone was useful for the survival of the patient for those 26 years. The drug interfered with the natural history of the meningioma, which generally evolves to death in such long follow-up durations without associated surgery or radiation therapy.

Mifepristone for uterine fibroids

BACKGROUND

Uterine fibroids are the most common benign uterine tumours present in women of reproductive age. Mifepristone (RU-486) competitively binds and inhibits progesterone receptors. Studies have suggested that fibroid growth depends on the sexual steroids. Mifepristone has been shown to decrease fibroid size. This review summarises the effects of mifepristone treatment on fibroids and the associated adverse effects as described in randomised controlled trials.

OBJECTIVES

To determine the efficacy and safety of mifepristone for the management of uterine fibroids in pre-menopausal women.

SEARCH METHODS

We searched the specialised register of the Cochrane Menstrual Disorders and Subfertility (Cochrane Menstrual Disorders and subfertility Review Group), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 4), MEDLINE, EMBASE, PsycINFO, and CINAHL (to November 2011). We handsearched a number of journals, and searched reference lists, databases of ongoing trials and the Internet. There were no language restrictions.

SELECTION CRITERIA

Only truly randomised controlled trials of mifepristone versus other forms of medical therapy or placebo in pre-menopausal women with confirmed uterine fibroids were included.

DATA COLLECTION AND ANALYSIS

Four authors independently extracted data and assessed trial quality. Data were analysed using the Peto odds ratios (OR) for dichotomous data and the weighted mean differences for continuous data, with 95% confidence intervals (CI). Meta-analyses were performed using the fixed-effect model.

MAIN RESULTS

Three studies involving 112 participants were included. Comparison interventions included different dosages of mifepristone, placebo and vitamin B tablets. There is evidence that treatment with mifepristone relieves heavy menstrual bleeding compared with placebo (Peto OR 17.84; 95% CI 6.72 to 47.38; 2 RCTs, 77 women, I(2) = 0%). Three studies (Bagaria 2009; Engman 2009; Fiscella 2006) were included in the meta-analysis of this comparison. There was no evidence of an effect of mifepristone on the fibroid volume (standardised mean difference (SMD) -0.02; 95% CI -0.38 to 0.41; 99 women). Two studies (Bagaria 2009; Fiscella 2006) were included in the meta-analysis of this comparison. There was no evidence of an effect of mifepristone on uterine volume (mean difference (MD) -77.24; 95% CI -240.62 to 86.14; 72 women). The pooled data suggest an increased adverse event (abnormal endometrial histology) in the mifepristone group compared to placebo (OR 31.65; 95% CI 4.83 to 207.35; 2 RCTs; 54 women; I(2) = 0%). Only one study (Bagaria 2009) reported endometrial hyperplasia at the end of the therapy (12/19 women in the mifepristone group versus 0/16 in the placebo group; OR 55.0; 95% CI 2.86 to 105.67). Engman 2009 found a significantly higher rate of cystic glandular dilatation in women in the mifepristone group (5/8 women biopsied) compared with the placebo group (1/11 women biopsied) (OR 16.67; 95% CI 1.36 to 204.03). One study (Fiscella 2006) suggested significant improvements (P < 0.001) for specific quality of life outcomes.

AUTHORS' CONCLUSIONS

Mifepristone reduced heavy menstrual bleeding and improved fibroid-specific quality of life. However, it was not found to reduce fibroid volume. Further well-designed, adequately powered RCTs are needed before a recommendation can be made on the use of mifepristone for the treatment of uterine fibroids.

Estradiol and progesterone-induced slowing of gonadotropin-releasing hormone pulse frequency is not reversed by subsequent administration of mifepristone

Subsequent to suppression of LH (GnRH) pulse frequency by progesterone (P) and estradiol (E(2)), LH pulse frequency remains slow for 7 days after P withdrawal if mid-luteal E(2) concentrations are maintained. This may reflect an ability of E(2) to potentiate the suppressive effects of low P levels. We explored this notion in a similar experimental paradigm by administering a P-receptor antagonist (mifepristone) after P withdrawal while continuing E(2). Studies were performed in seven ovulatory, non-obese women. Transdermal E(2) (0.2 mg/day) and oral micronized P (100 mg every 8 h) were started within 24 h of the LH surge and continued for 10 days. Subjects then underwent a 13-h blood sampling protocol for determination of LH pulse characteristics and various hormone concentrations. Oral P was then discontinued, and oral mifepristone (50, 100, or 200 mg daily) and transdermal E(2) (0.2 mg/day) were administered for 7 days, after which the above sampling protocol was repeated. Results with all mifepristone doses were similar and therefore pooled. Mean LH, LH amplitude, and mean FSH markedly decreased after 7 days of mifepristone, but LH pulse frequency did not change (3.3 +/- 1.5 vs. 2.4 +/- 1.5 pulses/13 h). Prolactin and androstenedione increased between the first and second admissions, with no changes in E(2), cortisol, testosterone, or DHEAS. In conclusion, blockade of P action by mifepristone does not reverse a suppressed LH pulse frequency within 7 days when E(2) concentrations are maintained, suggesting that P withdrawal alone may not explain the luteal-follicular increase of GnRH pulse frequency.

Mifepristone induced progesterone withdrawal reveals novel regulatory pathways in human endometrium

In women, a single dose of the antiprogestin mifepristone (RU486) in the secretory phase rapidly renders the endometrium unreceptive and is followed by endometrial breakdown and menstruation within 72 h. This model provides a system to identify progesterone-regulated genes, which may be involved in endometrial receptivity and the induction of menstruation. We used cDNA microarrays to monitor the response of the endometriuim over 24 h following administration of mifepristone in the mid-secretory phase. We identified 571 transcripts whose expression was significantly altered, representing 131 biochemical pathways. These include new progesterone regulated members of the Wnt, matrix metalloproteinase (MMP), prostaglandin (PG) and chemokine regulatory pathways. Transcripts involved in thyroid hormone metabolism and signalling such as type II iodothyronine deiodinase and thyroid receptors were also found to be highly regulated by progesterone antagonism in the endometrium. Transcripts required for thyroid hormone synthesis such as thyroid peroxidase (TPO) and thyroglobulin (TG) were also expressed, indicating that the endometrium may be a site of thyroxin production. These results add to the existing knowledge of the role of the Wnt, chemokine, MMP and PG pathways in receptivity and early menstrual events. They provide in vivo evidence supporting direct or indirect regulation of many new transcripts by progesterone. We have also identified for the first time the very early transcriptional changes in vivo in response to progesterone withdrawal. This greatly increases our understanding of the pathways leading to menstruation and may provide new approaches to diagnose and treat menstrual disorders.

Ultrasonographic appearance of the conceptus, fetal heart rate and profiles of pregnancy-associated glycoproteins (PAG) and prostaglandin F2α-metabolite (PGF2α-metabolite) after induction of fetal death with aglepristone during early gestation in cattle

A higher incidence of fetal losses, especially after the use of artificial reproduction techniques, asks for more intensive monitoring of bovine pregnancies. In this study, a model for fetal death (FD) was created by administering the antiprogesterone aglepristone twice, at Day 47 and 48 of gestation (n=5). Control heifers received the solvent (n=5). The temporal relationships between changes in ultrasonographic appearance of fetal fluids and membranes, fetal heart rate (FHR) and peripheral plasma levels of pregnancy-associated glycoprotein (PAG) and PGF2alpha-metabolite as determined by radioimmunoassay associated with FD were monitored at eight hour intervals around treatment. For the analysis of plasma levels the period under study was divided into five epochs (T1: before injection of aglepristone/solvent; T2: from first to second injection; T3: from second injection to FD; T4: from diagnosis of FD to 56 h later; T5: from 56 h to 104 h after diagnosis of FD). Control heifers produced healthy calves at term, but in treated heifers, FD occurred on average at 58 (range 48-80) h after first injection of aglepristone. Fetal death was always preceded by a visible reduction of the amount of allantoic fluid and by segregation of the allantochorionic membrane from the endometrium. FHR remained rather constant in both groups, but a (non-significant) drop in FHR around 8h before FD was diagnosed in four of five treated animals. All fetuses were expulsed after FD. Levels of PAG remained constant or even slightly increased in controls, but decreased in treated animals from T2 onward: levels during T4 and T5 significantly differed from those during T1 and from values in controls during T4 and T5 (P<0.01). PGF2alpha-metabolite levels did not change in the controls, but in the treated group they were significantly higher during T3 when compared to T1 (P<0.05). After this increase, a sharp decrease in PGF2alpha-metabolite level occurred, reaching a significantly lower level at T5 when compared to control animals (P=0.01). It is concluded, that FD induced by aglepristone is preceded by ultrasonographic visible changes in fetal membranes and fluids and a rise in PGF2alpha-metabolite and is followed by a drop in PAG and PGF2alpha-metabolite.

Mifepristone for luteal phase contraception

The concept of luteal phase contraception and the use of mifepristone in clinical trials, which allows for testing of its validity, as well as clinical pharmacological research designed to understand its mode of action, are reviewed. Early luteal phase administration has a variety of morphological, physiological and biochemical effects on the endometrium that are likely to interfere with embryonic-endometrial interactions. In fact, specifically designed pilot clinical trials as well as data derived from emergency contraception studies indicate that early luteal phase administration of mifepristone is highly effective in preventing pregnancy, with minimal disturbance of hormonal parameters or menstrual cyclicity. Mid and late luteal phase administration of mifepristone at doses above 25 mg are highly effective in inducing endometrial bleeding in nonconceptional cycles. However, administration of mifepristone within the period between implantation and expected menses fails to induce bleeding in a significant proportion of cases, and furthermore the bleeding induced does not insure the termination of pregnancy. While the data suggest there is potential for a once-a-month contraceptive pill, it is likely that no molecule endowed with partial agonistic properties, like mifepristone, will completely and reliably suppress the essential functions of progesterone in order to achieve contraceptive efficacy comparable to that of modern contraceptive methods.

Summary of evidence and research needs on the use of mifepristone in fertility regulation: consensus from the conference

The conference on the use of mifepristone to reduce unwanted pregnancy, sponsored by the World Health Organization, Concept Foundation and the Rockefeller Foundation, took place in Bellagio, Italy, between 24 and 28 September 2001. The objective of the conference was to review the scientific information and to evaluate the use of mifepristone for emergency contraception, luteal contraception and menstrual induction. Mifepristone is highly effective for emergency contraception but its advantages and disadvantages in comparison with levonorgestrel need to be further studied. Data indicate that mifepristone alone or in combination with misoprostol has potential for occasional use for women seeking help following repeated unprotected intercourse and/or when the interval between intercourse and treatment is more then 120 h. Administration of mifepristone immediately after ovulation seems to be an effective contraceptive method. However, before it can be used commonly, there is a need for a simple and inexpensive method to identify the right time in the cycle. Once-a-month treatment with mifepristone and misoprostol at the expected time of menstruation is not a practical method due to bleeding irregularities and timing of treatment. Menstrual induction with mifepristone and a suitable prostaglandin analogue is highly effective. A randomized comparison with manual vacuum aspiration is, however, needed before it can be recommended for routine use.

Mechanisms of action of mifepristone when used for emergency contraception

An emergency contraceptive method is used after coitus but before pregnancy occurs. The use of emergency contraception is largely underutilized worldwide. Recently, treatment with 10 mg mifepristone as a single dose has emerged as one of the most effective hormonal methods for emergency contraception, with very low side effects. However, the mechanism of action of mifepristone in humans when used for contraceptive purposes and especially for emergency contraception remains largely unknown. The objective of this review is to summarize available data on the effect of mifepristone on female reproductive functions relevant to emergency use of the compound. Taken together, available data from studies in humans indicate that the contraceptive effect of mifepristone used as a single low dose for emergency contraception is mainly due to impairment of ovarian function, either by blocking or postponing the luteinizing hormone surge, rather than to inhibiting of implantation.

Termination of mid-gestation pregnancy in bitches with aglepristone, a progesterone receptor antagonist

Six pregnancies were terminated in mid-gestation with aglépristone, a progesterone receptor antagonist, in 5 beagle bitches in order to determine the effects of aglépristone on plasma concentrations of prolactin and progesterone, the duration of the luteal phase, and the interestrous interval. In addition, the effects of aglépristone on the condition of the uterus and fetuses were examined by ultrasonography. After confirmation of pregnancy by ultrasonography, the dogs received 10 mg, s.c. aglépristone per kg body weight on 2 consecutive days at about 30 d post ovulation. Before, during and after treatment with aglépristone, plasma samples were collected for determination of the concentrations of prolactin and progesterone. The condition of the uterus and fetuses was assessed by ultrasonography the day before and at least 3 times a week for at least 2 wk after aglépristone administration. Termination of pregnancy occurred within 4 to 7 d after the start of aglépristone treatment, which was well tolerated, with no side-effects except slight vaginal discharge. The results of ultrasonographic examination indicated that aglépristone leads to abortion but not to fetal resorption. Elevated plasma concentrations of prolactin were observed during aglépristone treatment, while plasma progesterone levels remained unchanged. Pregnancy termination with aglépristone resulted in premature cessation of luteal function. In addition, the interestrous interval was shortened. The latter effects may be the consequence of actions of the progesterone receptor antagonist at the hypothalamus-pituitary level. In conclusion, aglépristone proved to be a safe and effective abortifacient in mid-gestation in the bitch. The results of the present study also indicated that aglépristone directly or indirectly influences pituitary function.

Effects of progesterone receptor blockers on human granulosa-luteal cell culture secretion of progesterone, estradiol, and relaxin

We have developed culture methods for human luteinizing granulosa cells (GLC) that support the timely and dynamic secretion of estrogen (estradiol-17beta; E(2)), progesterone (P(4)), and relaxin (Rlx) in patterns that mimic serum hormone concentrations during the luteal phase of the menstrual cycle. Additional hCG, to simulate rescue of the corpus luteum, prevented the normal decline in GLC hormone production. To test the importance of the P(4) receptor in P(4) production, GLC were treated in vitro with two P(4) receptor antagonists. Human GLC received one of two hCG support protocols: a Baseline group simulating the normal luteal phase or a Rescue group simulating early pregnancy. Baseline and Rescue groups were treated with either RU-486 or HRP2000 either early or late in the cell culture period. The effects of treatments or control on ovarian steroid and peptide hormone production were determined (significant difference was P < 0.05). In the Rescue group, late treatment resulted in an immediate and dramatic decline in E(2), P(4), and Rlx secretion to nearly nondetectable levels within 1 day after treatment, and hormones remained depressed for the remaining 10 days of culture. In contrast, early treatment resulted in a decline in steroid hormone secretion that returned to control levels within 5 days of cessation of treatment, and Rlx secretion was delayed for approximately 5 days more than in controls. The data support the hypothesis that P(4) may be a required autocrine factor, not only for its own production but also for the maintenance of full endocrine function of the corpus luteum.

Preliminary report on the treatment of endometriosis with low-dose mifepristone (RU 486)

OBJECTIVE

We have previously shown that treatment with mifepristone, 50 to 100 mg daily, results in amenorrhea, anovulation, and symptomatic improvement in women with endometriosis. In this study we lowered the dose to 5 mg daily to determine whether clinical efficacy is altered without other adverse actions.

STUDY DESIGN

After a baseline cycle, seven women with endometriosis were given mifepristone, 5 mg daily, for 6 months. Daily symptom inventories were recorded. Laparoscopy was performed during the sixth month of therapy.

RESULTS

Pelvic pain improved in six of seven patients. Cyclic bleeding ceased in all patients, but four of the seven patients complained of irregular bleeding. Surgical staging at the conclusion of the study (five of seven patients) did not detect a change in endometriosis.

CONCLUSIONS

Mifepristone, 5 mg daily, resulted in symptomatic improvement, but did not stabilize the endometrium. From our experience with three doses of mifepristone, we would recommend a dose of 50 mg be used for continued investigations.

Mifepristone (RU486): a review

OBJECTIVE

To review the literature concerning the mechanism of action and pharmacodynamics of mifepristone (RU486), potential new uses of RU486, and its current use not only as an abortifacient but also as therapy for endometriosis, leiomyoma, breast cancer, and meningioma.

DATA IDENTIFICATION AND SELECTION

Studies that relate to RU486 were identified through a MEDLINE search.

CONCLUSION(S)

RU486 is an 11 beta-dimethyl-amino-phenyl derivative of norethindrone with a high affinity for P and glucocorticoid receptors. The receptor binding is not followed by transcription of P-dependent genes. Mifepristone effectively blocks P receptors in the placenta, resulting in the termination of pregnancy. In addition, it has been used in the treatment of leiomyomata, endometriosis, advanced breast cancer, and meningioma. It is a powerful tool to study the molecular action of P and in the future may be used as an estrogen-free contraceptive.

Modern medical management of endometriosis

The modern medical management of endometriosis has changed considerably since the first attempts were made to control this disease hormonally over four decades ago. Currently, there are multiple choices for the clinician and patient, including oral contraceptives, danazol, GnRH agonist analogues, and gestrinone. Several advances have been made in the use of GnRH agonists in preventing some of the untoward effects of prolonged hypoestrogenism. These add-back regimens provide the best therapy available today for prolonged medical control of endometriotic symptoms. The antiprogesterones (RU-486) hold promise for the future, but are still in the investigational stage of development.

RU486 (mifepristone): mechanisms of action and clinical uses

RU486 (mifepristone) has proved to be a remarkably active antiprogesterone and antiglucocorticosteroid agent in human beings. The mechanism of action involves the intracellular receptors of the antagonized hormones (progesterone and glucocorticosteroids). At the molecular level, the most important features are high binding affinity to the receptor, interaction of the phenylaminodimethyl group in the 11 beta-position with a specific region of the receptor binding pocket, and RU486-induced transconformation differences in the ligand-binding domain. These particularities have consequences at different steps of the receptor function as compared with agonists. However, the reasoning cannot be limited to the RU486-receptor interaction, and, for instance, there is the possibility of a switch from antagonistic property to agonist activity, depending on the intervention of other signaling pathways. It would be desirable to have derivatives with only one of the two antagonistic properties (antiprogestin, antiglucocorticosteroid) in spite of similarities between steroid structures, receptors involved, and responsive machineries in target cells. Clinically, the RU486-plus-prostaglandin method is ready to be used on a large scale and is close to being as convenient and safe as any medical method of abortion may be. The early use of RU486 as a contragestive as soon as a woman fears a pregnancy she does not want will help to defuse the abortion issue. Research should now be conducted to define an efficient and convenient contraceptive method with RU486 or other antiprogestins. The usefulness of RU486 for obstetric indications, including facilitation of difficult delivery, has to be assessed rapidly. Gynecologic trials, particularly in leiomyomata, should be systemically continued. The very preliminary results obtained with tumors, including breast cancers, indicate that further studies are necessary.

Endometrial effects of RU486 in primates--antiproliferative action despite signs of estrogen action and increased cyclin-B expression

Continuous antiprogestin administration to hormone replaced, castrate monkeys inhibits estrogen-induced endometrial proliferation through mechanisms which remains unclear. To elucidate the molecular mechanisms of RU486-induced endometrial suppression, we treated six intact female cynomolgus monkeys on cycle days 2-22 sequentially with placebo, RU486 (1 mg/kg/day) and levonorgestrel (LNG) (2 microg/kg/day) intramuscularly (i.m.), with uterine wedge sections and endometrial biopsies collected on day 22 of each cycle. The uterine sections were evaluated for morphology, mitosis and proliferating cell nuclear antigen (PCNA) immunohistochemistry. Changes in the mRNA levels of ER, PR, cyclin-B and tumour suppressor gene p21 were assessed using co-amplification with beta-actin by reverse transcriptase-polymerase chain reaction (RT-PCR). Administration of RU486 uniformly resulted in characteristic suppression of endometrium with few mitosis, dense stroma and simple glands, whereas the effects of LNG were less uniform. Following RU486 administration, the levels of endometrial ER and PR mRNA were comparable to proliferative phase endometrium, and significantly higher than those seen in the secretory endometrium, indicating that some of the biological actions of E2 were not inhibited during RU486 treatment. Despite scarce mitosis, PCNA was readily detectable in all samples. Curiously, in comparison to secretory phase controls, the levels of cyclin-B, but not p21, mRNA were markedly increased following RU486. The effects of LNG on the levels of these mRNA species varied, with mean levels falling between those of the secretory phase controls, and RU486-treated specimens. The increase in cyclin-B mRNA and lack of mitosis suggests that anti-proliferative actions of RU486 in the primate endometrium might be associated with a cell-cycle block at the G2-M interphase. Whether mechanisms similar to these are associated with the beneficial clinical effects of RU486 seen in the treatment of various hormone dependent maladies remains to be determined.

Focal cellular origin and regulation of interstitial collagenase (matrix metalloproteinase-1) are related to menstrual breakdown in the human endometrium

Recent studies suggest that interstitial collagenase (MMP-1) is an essential enzyme in the early events leading to menstruation. This study analyses its cellular origin, regulation and relation to extracellular matrix breakdown in the human endometrium, both in cultured and non-cultured samples. The source of MMP-1 was identified by in situ hybridization and by immunohistochemistry on serial sections. This was compared with the immunolocalization of other MMPs, steroid receptors, macrophages, and laminin. In non-cultured endometrium, MMP-1 was only expressed during the perimenstrual period. It was either restricted to superficial foci of stromal cells or extended towards the entire functional layer. MMP-1 expression remarkably correlated with matrix breakdown, as assessed by silver staining, and was prominent at the periphery of shedding fragments and along some arterioles. In cultured non-menstrual explants, MMP-1 expression was induced within two days after deprivation of sex steroids. Both in cultured and non-cultured samples, progesterone receptors were not detectable in epithelial cells at foci of MMP-1 expression. The same stromal cells could synthesize MMP-1, MMP-2 (gelatinase A) and MMP-3 (stromelysin-1), as well as laminin, and did not correspond to macrophages. In conclusion, MMP-1 is focally expressed in stromal cells of the functional layer of the endometrium, when and where steroid receptors disappear, and especially where tissue breakdown is prominent. These observations point to an essential role for MMP-1 in the early stages of menstruation.

Mifepristone and ovarian function

In summary, RU 486 has been a powerful instrument in delineating progesterone action on the ovary. However, early experiments using RU 486 must be interpreted with the understanding that systemic administration of the antiprogestin may have had extraovarian sites of action, such as at the hypothalamic-pituitary axis or at the adrenal, that in turn led to indirect ovarian responses. Treatment with progesterone, agonist, or antagonist at periods during which the ovary lacks progesterone receptors would further suggest extraovarian sites of action or nongenomic mechanisms of action. Furthermore, the dose of ligand or antagonist administered and the hormonal milieu at the time of administration may dictate the ovarian response (Espey L, personal communication). For example, low doses of exogenous progesterone may elicit a biologic response, whereas high doses are without effect or may inhibit the biologic effect observed at lower doses. Although RU 486 is classically described as an antiprogestin, agonist actions have been observed in addition to its the well documented antiglucocorticoid effects. All of these variables may contribute to the confounding observations of progesterone and RU 486 action on the ovary. Regardless of these caveats, experimental paradigms have demonstrated that RU 486, either indirectly or directly, regulates ovarian folliculogenesis, stimulates and/or inhibits steroidogenesis depending on the species and time of RU 486 administration, inhibits ovulation, and modulates luteal function. These findings supports a progesterone-dependent mechanism in these varied aspects of ovarian function.

Contraception with anti-progesterone

Anti-progesterones have potential as contraceptives, acting either by the inhibition of ovulation or the inhibition of endometrial development. Clinical studies have shown that once-a-month treatment with Mifepristone in the early luteal phase is an effective contraceptive method, and that emergency post-coital contraception with Mifepristone is at least as effective as other methods currently used. Recent studies indicate that the endometrium is more susceptible to Mifepristone than are the hypothalamic and pituitary regions, and it may therefore be possible to develop a new contraceptive method based on low daily or once-weekly doses of Mifepristone that does not influence ovarian function.

Treatment of endometriosis with the antiprogesterone mifepristone (RU486)

OBJECTIVE

To evaluate the safety and efficacy of an antiprogesterone (mifepristone, RU486; Roussel-Uclaf, Romaineville, France) on endometriosis.

DESIGN

An open, prospective clinical trial.

SETTING

The clinical practice of an academic faculty.

PATIENTS

Nine women with endometriosis were studied.

INTERVENTIONS

RU486 (50 mg/d) was administered for 6 months.

MAIN OUTCOME MEASURES

Daily symptom inventories and urinary steroid metabolites were assessed before, during, and after treatment. Blood for hormone analysis was obtained weekly for 4 weeks and monthly thereafter. The extent of endometriosis, bone mineral density, circadian rhythm of cortisol, and LH pulsatility were determined before and after treatment. Safety laboratory measurements were made before and at 1, 2, and 6 months of treatment.

RESULTS

Pelvic pain and uterine cramping improved in all patients. Endometriosis regressed by 55%. All patients exhibited endocrine features of anovulatory amenorrhea without hypoestrogenism. A rise in serum LH and T levels was observed during the first month of treatment and one patient developed an elevation of liver transaminases during the last month of treatment. All other measurements were unchanged.

CONCLUSION

RU486 appears to be effective in improving the symptoms and causing regression of endometriosis in the absence of significant side effects.

Effect of daily low dose mifepristone on the ovarian cycle and on dynamics of follicle growth

BACKGROUND AND OBJECTIVE

The antiprogestin mifepristone has been shown to disrupt folliculogenesis and endometrial maturation and, therefore, has the potential to be used as a novel form of contraception. The purpose of this study was to investigate further the effects of daily administration of a low dose of mifepristone (2mg) on the ovarian cycle and on the dynamics of follicle growth.

SUBJECTS

Six healthy female volunteers were given 2mg mifepristone daily for 30 days following an ovulatory control cycle.

MEASUREMENTS

Follicle growth was monitored with transvaginal ultrasonography and hormonal measurements in blood and urine were used to monitor effects on the ovarian cycle. In addition, concentrations of cortisol and ACTH in serum were measured to assess the effects of mifepristone on the pituitary-adrenal axis.

RESULTS

Treatment with mifepristone retarded the follicular growth rate in all women (P = 0.01). Ovulation was inhibited in 4 of 6 subjects and appeared to be mediated through an effect on the hypothalamo-pituitary axis, as no surge of FSH or LH occurred. In these subjects the dominant follicle continued to grow and developed into a persistent follicle. In two cases the persistent follicle remained functional and ovulation occurred soon after stopping treatment. In the remaining two subjects, the dominant follicle developed into a non-functioning cyst ( > 30 mm) which persisted for one month after the end of the post-treatment cycle. In the two subjects who ovulated, the LH surge was delayed by 6 and 7 days but was followed by a luteal phase of normal length. There was no significant change in the concentration of ACTH or cortisol suggesting that treatment with mifepristone in this dose has little if any effect on the pituitary-adrenal axis.

CONCLUSION

These findings add further evidence to support the contraceptive potential of mifepristone through effects on follicular development and on the menstrual cycle.

Treatment with a progesterone antagonist ZK 98.299 delays endometrial development without blocking ovulation in bonnet monkeys

The effects of an antiprogestin ZK 98.299 (onapristone) on serum levels of estradiol and progesterone, and on the endometrial morphology were studied in adult bonnet monkeys. Twelve animals having menstrual cycles of normal duration (24 to 30 days) were randomly distributed into 4 equal groups. The animals in Group 1 were treated (s.c.) with the vehicle (benzyl benzoate: castor oil, 1:10), and in Groups 2, 3 and 4 with 5 mg, 10 mg, or 20 mg ZK 98.299 once-a-week, respectively. Treatment was initiated on day 1 of the menstrual cycle and each animal in Groups 1, 2 and 3 was treated for two consecutive cycles. Since the treatment cycle length of animals in Group 4 was considerably prolonged, they were treated for one menstrual cycle only. Endometrial biopsy was taken around day 20 of the second treatment cycle of first three groups and around day 50 of the 4th group of animals. Treatment with vehicle or 5 mg ZK 98.299 had no significant effect on the menstrual cycle length. Treatment with 10 mg dose had no effect in two animals and prolonged the cycle length in one, whereas, further increase in the dose to 20 mg prolonged the cycle length in all the animals. The duration of menses was generally reduced. Treatment with vehicle or different doses of ZK 98.299 had no effect on ovulation. In animals treated with 5 or 10 mg dose, the pattern of mid cycle rise in serum estradiol levels and progesterone levels during the luteal phase of both treatment cycles were comparable to those of vehicle-treated animals and were suggestive of normal ovulatory cycles. On the other hand, in animals treated with the higher dose (20 mg/week), progesterone levels during the luteal phase were significantly reduced and were indicative of luteal insufficiency. The hormonal data during the treatment period of this group of animals was suggestive of two distinct ovarian cycles indicating that the menstrual bleeding during the treatment period was probably very scanty. Treatment with ZK 98.299 impaired the endometrial development in a dose-dependent manner. In vehicle-treated animals, the endometrium had large and tortous glands with secretions. Treatment with ZK 98.299 caused atrophic changes in the glands as well as in the stroma. The height of the epithelial cells was markedly decreased and they became small and inactive. This study, therefore, suggests that treatment with low doses of antiprogestin ZK 98.299 at weekly intervals does not block folliculogenesis or ovulation, but has an inhibitory effect on the endometrium.(ABSTRACT TRUNCATED AT 250 WORDS)

Mode of action of RU 486

RU 486 is a 19-norsteroid which has a specific high affinity binding to the progesterone and glucocorticoid receptor. It is generally accepted that RU 486 acts as a pure progesterone antagonist almost without agonistic activity. RU 486 acts mainly directly on the target organ, such as the endometrium, but also to some extent indirectly through an effect on the pituitary gonadotrophin secretion. The effect of RU 486 during the menstrual cycle is dependent on time of treatment. Treatment before ovulation will result in a prolongation of the proliferative phase of the menstrual cycle, while treatment during the mid- and late luteal phase will invariably induce bleeding, often followed by a second bleeding episode at the expected time of menstruation. The only treatment period which does not influence the menstrual cycle is treatment immediately following ovulation. Treatment during the proliferative phase has no effect on endometrial morphology but inhibits follicular development and delays oestrogen and LH surge. Treatment on the first days following ovulation has no effect on ovarian steroid concentration, but will significantly delay endometrial development, cause a change in the concentration of oestrogen and progesterone receptor concentration enzyme activity and production of substances thought to be progesterone dependent. The change in endometrial development is sufficient to prevent implantation. In mid- and late luteal phase, treatment with RU 486 will result in endometrial shedding in spite of normal progesterone levels. Post-ovulatory treatment with RU 486 will also significantly change uterine contractility. In early pregnancy, withdrawal of progesterone inhibition will result in uterine contractility and a significant increase in the sensitivity of the myometrium to prostaglandin.(ABSTRACT TRUNCATED AT 250 WORDS)

Mifepristone (RU 486) compared with high-dose estrogen and progestogen for emergency postcoital contraception

BACKGROUND

Mifepristone (RU 486) is a synthetic steroid with potent antiprogestational and antiglucocorticoid properties that provides an effective medical method of inducing abortion in early pregnancy. Since progesterone is essential for implantation, we tested the use of mifepristone for emergency postcoital contraception.

METHODS

We studied 800 women and adolescents requesting emergency postcoital contraception who had had unprotected intercourse within the preceding 72 hours. A total of 398 women and adolescents were randomly assigned to treatment with 100 micrograms of ethinyl estradiol and 1 mg of norgestrel, each given twice 12 hours apart (standard therapy), and 402 women and adolescents were randomly assigned to receive 600 mg of mifepristone.

RESULTS

None of the women and adolescents who received mifepristone became pregnant, as compared with four of those who received standard therapy; the difference in failure rates between the two regimens was not statistically significant. The number of pregnancies in each group was significantly lower than the number expected according to calculations based on the day of the cycle during which intercourse had taken place (P less than 0.001). In many subjects the stage of the cycle as calculated by menstrual history was inconsistent with measurements of plasma progesterone or urinary pregnanediol excretion. The subjects treated with mifepristone reported less nausea (40 percent vs. 60 percent) and vomiting (3 percent vs. 17 percent) on the day of treatment, as well as lower rates of other side effects, than the subjects treated with the standard regimen, but they were more likely to have a delay in the onset of the next menstrual period (42 percent vs. 13 percent).

CONCLUSIONS

Mifepristone is a highly effective postcoital contraceptive agent that, if used more widely, could help reduce the number of unplanned and unwanted pregnancies.

Interruption of endometrial maturation without hormonal changes by an antiprogesterone during the first half of luteal phase of the menstrual cycle: a contraceptive potential

OBJECTIVE

To examine hormonal and endometrial responses to intermittent low-dose RU486 administration in the luteal phase of the menstrual cycle.

DESIGN

Prospective open trial in which subjects serve as their own controls.

PATIENTS/PARTICIPANTS

Eight normal cycling women.

INTERVENTIONS

RU486 (10 mg, orally) was administered 5 and 8 days after urinary luteinizing hormone (LH) surge of treatment cycle.

MAIN OUTCOME MEASURES

Daily serum concentrations of LH, follicle-stimulating hormone, estradiol (E2), and progesterone (P) were determined in control, treatment, and recovery cycles (n = 5) or treatment and recovery cycles (n = 3). Changes in endometrial morphology and immunohistochemical staining for P receptor (PR) and E2 receptor (ER) were determined during control (or recovery) and treatment cycles.

RESULTS

Cycle length and hormonal patterns were unaltered after treatment with RU486. As demonstrated by reduced stromal edema and delayed glandular development, endometrial dyssynchrony occurred in all eight treatment cycles. In addition, seven of eight treatment cycle endometria demonstrated a decrease in PR staining without consistent change in ER staining.

CONCLUSIONS

Two low doses of RU486 given 72 hours apart during the luteal phase of the cycle disrupted ongoing endometrial maturation without altering the hormonal and time course of the menstrual cycle. This study provides a basis for the development of a novel form of luteal contraception.

A randomized clinical trial of mifepristone (RU486) for induction of delayed menses: efficacy and acceptability

Mifepristone (RU486) should be useful for inducing menstrual bleeding in women with menses delayed up to 10 days. We evaluated this potential use for "menstrual regulation" in a randomized clinical trial with 16 women, half of whom received a single 600 mg dose and half of whom received a placebo. Four of eight women in each treatment group proved to be pregnant. Seven of eight who received mifepristone were not pregnant at two-week follow-up, in contrast to four of eight who received the placebo (p = 0.15). Mifepristone may hold promise for "menstrual regulation" for women who do not have access to medical confirmation of pregnancy or who choose not to have this determination made.

RU486 and the early nineties

RU486 is a very powerful antisteroid hormone compound. Its antiprogestin activity particularly leads to clinical application in reproductive medicine. Its use for voluntary pregnancy interruption is only one aspect of its medical potentiality.

Mifepristone (RU486) alone or in combination with a prostaglandin analogue for termination of early pregnancy: a review

The availability of a medical mode of termination of early pregnancy by the administration of RU486, an antiprogesterone alone, or in combination with one of the PG analogues significantly reduces the maternal morbidity and mortality associated with the classical surgical abortion. RU486 given alone in early pregnancy induces complete abortion in 60% to 85% of cases, and when combined with prostaglandin analogues, gemeprost or sulprostone, reaches a success rate of 95% to 99%. RU486 may also be of potential value in the medical treatment of ectopic pregnancy. Its use as a postcoital contraception is suggested, but further research is required to determine whether RU486 can be used on a once-a-month basis for contraception.

Endocrine responses to long-term administration of the antiprogesterone RU486 in patients with pelvic endometriosis

OBJECTIVE

To examine endocrine and clinical responses to long-term administration of RU486 in patients with endometriosis.

DESIGN

Prospective open trial.

SETTING

Faculty practice of the authors.

PATIENTS, PARTICIPANTS

Six normally cycling women with endometriosis were recruited.

INTERVENTIONS

Subjects received RU486 100 mg/d for 3 months.

MAIN OUTCOME MEASURE(S)

Hormonal changes during RU486 were compared with control data obtained in the preceding cycle during the early follicular phase. Clinical responses were determined by patient assessment and second-look laparoscopy.

RESULTS

All women became amenorrheic, and daily urinary levels of ovarian steroid metabolites remained acyclic. Mean luteinizing hormone (LH) (P less than 0.02) and LH pulse amplitude (P less than 0.05) were increased without changes in LH pulse frequency. An antiglucocorticoid effect was demonstrated by an increase in serum cortisol (P less than 0.01) and adrenocorticotropic hormone (P less than 0.05) levels. Treatment resulted in an improvement in pelvic pain in all subjects without significant change in the extent of disease as evaluated by follow-up laparoscopy.

CONCLUSIONS

Daily administration of RU486 results in acyclic ovarian function and improvement in the subjective painful symptoms of endometriosis.

Antiprogestin treatment decreases midluteal luteinizing hormone pulse amplitude and primarily exerts a pituitary inhibition

Mifepristone (RU 486), a synthetic steroid with antiprogesterone receptor activity, was given with and without naloxone hydrochloride to six women in the midluteal phase to investigate the role of progesterone in the modulation of endogenous opioid activity and the secretion of luteinizing hormone and cortisol. Subjects were evaluated during four sequential monthly admissions during which multiple blood samples were obtained every 15 minutes for 8 hours. Patients were studied during a baseline cycle, after administration of RU 486 alone (100 mg/day), naloxone with RU 486, and naloxone alone. After administration of RU 486 there was a significant decline in total luteinizing hormone secretion (p less than 0.01) and luteinizing hormone pulse amplitude (p less than 0.05), but compared with baseline there was no significant change in luteinizing hormone pulse frequency. After infusion of naloxone there was a significant increase in mean luteinizing hormone values (p less than 0.05) and luteinizing hormone pulse frequency (p less than 0.01) but no change in pulse amplitude. There was no significant difference in mean luteinizing hormone values or luteinizing hormone pulse amplitude and frequency between administration of RU 486 and naloxone plus RU 486. Administration of naloxone alone, RU 486 alone, and RU 486 plus naloxone caused a significant increase in cortisol as compared with baseline cycles (p less than 0.05). These data further support the notion that progesterone is important in the control of luteinizing hormone secretion and suggest that progesterone may primarily influence luteinizing hormone pulse amplitude and pituitary release of luteinizing hormone during the luteal phase.

Late luteal administration of the antiprogesterone RU486 in normal women: effects on the menstrual cycle events and fertility control in a long-term study

Twelve regularly cycling women, with contraindications to other methods of contraception, received RU486 (Roussel UCLAF, Romainville, France), once a month as a method of fertility control. The study was designed for 18 consecutive cycles. Each patient recorded basal body temperature, detected urinary luteinizing hormone peak, and collected saliva samples during each luteal phase for progesterone (P) determinations. A single dose of RU486, 600 mg, was given on the day before the expected date of the menses and 8 days later in case of continuing pregnancy after the first dose. Blood samples were collected for estradiol, P, and beta-human chorionic gonadotropin analyses on these two occasions. The compliance was poor and the results of only 137 cycles were obtained. The menstrual cyclicity was not significantly modified during this long-term study. Of the 137 cycles, 22 pregnancies occurred (16%), and 4 (18.2%) were not interrupted by the second dose of RU486. Thus, because of the high failure rate, use of RU486 at the time of the natural P withdrawal cannot be advocated as a "once-a-month" contragestive agent.

Ovarian steroid regulation of pulsatile luteinizing hormone release during early gestation in the rat

Abstract The object of this study was to examine ovarian regulation of pulsatile luteinizing hormone (LH) secretion during early gestation. This was done primarily by analyzing pulsatile LH release in rats that were either sham ovariectomized (OVX) on Day 7 of pregnancy, implanted with empty Silastic capsules, and bled on Day 8, or OVX on Day 7, immediately implanted with Silastic capsules producing plasma levels of estradiol and/or progesterone characteristic of Day 7 to 8 of pregnancy, and bled on Day 8. In addition, the role of progesterone in regulating pulsatile LH secretion was also examined by administration of the progesterone receptor antagonist, RU486, on Day 7 and examining pulsatile LH release on Day 8 of pregnancy. OVX caused a marked increase in LH pulse amplitude and frequency within 24 h. Replacement with physiological plasma levels of estradiol or progesterone alone had no suppressive effect on this OVX-induced increase in pulsatile LH secretion. Restoration of physiological plasma levels of both estradiol and progesterone returned LH pulse amplitude to values seen in sham OVX controls, and prevented the OVX-induced increase in LH pulse frequency. The group mean LH pulse frequency tended to be less in estradiol + progesterone-treated rats than in sham OVX controls, but this difference was not statistically significant. RU486 blocked uterine progesterone receptors as evidenced by endometrial hemorrhaging. In agreement with the OVX + steroid replacement data, RU486 administration also resulted in increases in LH pulse amplitude and frequency. These data demonstrate that the frequency and amplitude of LH pulses on Day 8 of gestation are held in check by negative feedback signals coming from the ovary. Neither steroid alone exerts any suppressive influence over pulsatile LH secretion during early gestation, but both steroids acting together exert a prominent negative feedback regulation on the pulsatile LH release process.

Antiprogesterone RU 486--a drug for non-surgical abortion

RU 486 is the first steroidal antiprogesterone in clinical use. It acts by binding to progesterone receptor, thus blocking the effects of progesterone at the uterine level, and provoking endometrial necrosis and shedding. RU 486 can, therefore, be used to interrupt early human pregnancy. In pregnancies of up to 7-8 weeks duration, the rate of complete abortions with RU 486 has ranged from 50% to 90%. The success rate can, however, be augmented up to 95%-100% by combining RU 486 with a low dose prostaglandin. RU 486 induced abortion has been well tolerated by women and highly acceptable to them. The bleeding starts 2-3 days after RU 486 administration lasting for 12-14 days. Possible clinical uses of RU 486 include induction of menstruation, late post-coital contraception, induction of labour after intrauterine fetal death, preoperative cervical ripening and treatment of progesterone receptor positive mammary tumours. When administered in the follicular phase of the cycle, RU 486 inhibits follicular development. In addition, the antiglucocorticoid properties of RU 486 have been used in symptomatic treatment of hypercortisolemia of Cushings disease. The pharmacokinetics of RU 486 are characterised by high micromolar serum concentrations, long half-life of 26-48 hours and substantial metabolism after oral administration. Although effective and well tolerated, RU 486 has aroused great moral controversy, which is currently hampering further testing and distribution of the drug. So far RU 486 has been accepted for termination of pregnancy in France and in the Peoples Republic of China, to be used with prostaglandins and under strict medical surveillance.