Pharmacokinetics and metabolism of RU 486

Selective Progesterone Receptor Modulators-Mechanisms and Therapeutic Utility

Selective progesterone receptor modulators (SPRMs) are a new class of compounds developed to target the progesterone receptor (PR) with a mix of agonist and antagonist properties. These compounds have been introduced for the treatment of several gynecological conditions based on the critical role of progesterone in reproduction and reproductive tissues. In patients with uterine fibroids, mifepristone and ulipristal acetate have consistently demonstrated efficacy, and vilaprisan is currently under investigation, while studies of asoprisnil and telapristone were halted for safety concerns. Mifepristone demonstrated utility for the management of endometriosis, while data are limited regarding the efficacy of asoprisnil, ulipristal acetate, telapristone, and vilaprisan for this condition. Currently, none of the SPRMs have shown therapeutic success in treating endometrial cancer. Multiple SPRMs have been assessed for efficacy in treating PR-positive recurrent breast cancer, with in vivo studies suggesting a benefit of mifepristone, and multiple in vitro models suggesting the efficacy of ulipristal acetate and telapristone. Mifepristone, ulipristal acetate, vilaprisan, and asoprisnil effectively treated heavy menstrual bleeding (HBM) in patients with uterine fibroids, but limited data exist regarding the efficacy of SPRMs for HMB outside this context. A notable class effect of SPRMs are benign, PR modulator-associated endometrial changes (PAECs) due to the actions of the compounds on the endometrium. Both mifepristone and ulipristal acetate are effective for emergency contraception, and mifepristone was approved by the US Food and Drug Administration (FDA) in 2012 for the treatment of Cushing's syndrome due to its additional antiglucocorticoid effect. Based on current evidence, SPRMs show considerable promise for treatment of several gynecologic conditions.

The selective glucocorticoid receptor antagonist CORT125281 has tissue-specific activity

Glucocorticoids mediate numerous essential processes in the human body via binding to the glucocorticoid receptor (GR). Excessive GR signaling can cause disease, and GR antagonists can be used to treat many symptoms of glucocorticoid-induced pathology. The purpose of this study was to characterize the tissue-specific properties of the selective GR antagonist CORT125281. We evaluated the antagonistic effects of CORT125281 upon acute and subchronic corticosterone exposure in mice. In the acute corticosterone setting, hypothalamus-pituitary-adrenal-axis activity was investigated by measurement of basal- and stress-induced corticosterone levels, adrenocorticotropic hormone levels and pituitary proopiomelanocortin expression. GR signaling was evaluated by RT-PCR analysis of GR-responsive transcripts in liver, muscle, brown adipose tissue (BAT), white adipose tissue (WAT) and hippocampus. Pretreatment with a high dose of CORT125281 antagonized GR activity in a tissue-dependent manner. We observed complete inhibition of GR-induced target gene expression in the liver, partial blockade in muscle and BAT and no antagonism in WAT and hippocampus. Tissue distribution only partially explained the lack of effective antagonism. CORT125281 treatment did not disinhibit the hypothalamus-pituitary-adrenal neuroendocrine axis. In the subchronic corticosterone setting, CORT125281 partially prevented corticosterone-induced hyperinsulinemia, but not hyperlipidemia and immune suppression. In conclusion, CORT125281 antagonizes GR transcriptional activity in a tissue-dependent manner and improves corticosterone-induced hyperinsulinemia. Tailored dosing of CORT125281 may allow tissue-specific inhibition of GR transcriptional activity.

Inhibition of adenovirus infection by mifepristone

The repurposing of drugs approved by the regulatory agencies for other indications is emerging as a valuable alternative for the development of new antimicrobial therapies, involving lower risks and costs than the de novo development of novel antimicrobial drugs. Adenovirus infections have showed a steady increment in recent years, with a high clinical impact in both immunosuppressed and immunocompetent patients. In this context, the lack of a specific drug to treat these infections supports the search for new therapeutic alternatives. In this study, we examined the anti-HAdV properties of mifepristone, a commercially available synthetic steroid drug. Mifepristone showed significant in vitro anti-HAdV activity at low micromolar concentrations with little cytotoxicity. Our mechanistic assays suggest that this drug could affect the microtubule transport, interfering with the entry of the virus into the nucleus and therefore inhibiting HAdV infection.

Resetting the Stress System with a Mifepristone Challenge

Psychotic depression is characterized by elevated circulating cortisol, and high daily doses of the glucocorticoid/progesterone antagonist mifepristone for 1 week are required for significant improvement. Using a rodent model, we find that such high doses of mifepristone are needed because the antagonist is rapidly degraded and poorly penetrates the blood–brain barrier, but seems to facilitate the entry of cortisol. We also report that in male C57BL/6J mice, after a 7-day treatment with a high dose of mifepristone, basal blood corticosterone levels were similar to that of vehicle controls. This is surprising because after the first mifepristone challenge, corticosterone remained elevated for about 16 h, and then decreased towards vehicle control levels at 24 h. At that time, stress-induced corticosterone levels of the 1xMIF were sevenfold higher than the 7xMIF group, the latter response being twofold lower than controls. The 1xMIF mice showed behavioral hyperactivity during exploration of the circular hole board, while the 7xMIF mice rather engaged in serial search patterns. To explain this rapid reset of corticosterone secretion upon recurrent mifepristone administration, we suggest the following: (i) A rebound glucocorticoid feedback after cessation of mifepristone treatment. (ii) Glucocorticoid agonism in transrepression and recruitment of cell-specific coregulator cocktails. (iii) A more prominent role of brain MR function in control of stress circuit activity. An overview table of neuroendocrine MIF effects is provided. The data are of interest for understanding the mechanistic underpinning of stress system reset as treatment strategy for stress-related diseases.

Stress affects expression of the clock gene Bmal1 in the suprachiasmatic nucleus of neonatal rats via glucocorticoid-dependent mechanism

AIM

The reactivity of the circadian clock in the suprachiasmatic nuclei (SCN) to stressful stimuli has been controversial but most studies have confirmed the resilience of the SCN to stress. We tested the hypothesis that during a critical period shortly after birth, the developing SCN clock is affected by glucocorticoids.

METHODS

Mothers of 2 rat strains with different sensitivities to stress, that is Wistar rats and spontaneously hypertensive rats (SHR), and their pups were exposed to stressful stimuli every day from delivery, and clock gene expression profiles were detected in the 4-day-old pups' SCN. Levels of glucocorticoids in plasma were measured by LC-MS/MS. The glucocorticoid receptors antagonist mifepristone was administered to pups to block the effect of the glucocorticoids.

RESULTS

The glucocorticoid receptors were detected at the mRNA and protein levels in the SCN of 4-day-old pups. The exposure of mothers to stressful stimuli elevated their plasma glucocorticoid levels. In Wistar rat pups, combination of daily maternal stress with their manipulation increased the plasma glucocorticoid levels and shifted the Bmal1 rhythm in the SCN which was completely blocked by mifepristone. In contrast, in SHR pups, maternal stress on its own caused phase shift of the Bmal1 expression rhythm in the SCN but the effect was mediated via glucocorticoid-independent mechanism. The Per1 and Per2 expression profiles remained phase-locked to the light/dark cycle.

CONCLUSION

The results demonstrate that the SCN is sensitive to stressful stimuli early after birth in pups maintained under light/dark conditions and the effect is mediated via glucocorticoid-dependent pathways.

Drug Methods for Arteficial Termination of Unwanted Pregnancy

All medical and surgical procedures are carried out in order to premature termnination of pregnancy, can be divided on medicament and surgical methods, according to the way of procedure.

Medications used today in order to break unwanted pregnancy are inhibitors of the synthetics of progesterone and antiprogesterone, prostaglandini and antimetabolite.

Mifepristone is a derivate of norethidrone, binds to the progesterone receptor with an affinity similar progesterone, but it does not activate them so as to act as an antiprogestine.

Metotrexat is an antimetabolite and is used in gynecology practice for more indication areas. It is used the most often in conservative treatment of ectopical pregnancy. Because of low price and accessibility in order to mifepristone, it was used for application in drug methods of inducative abortions.

Misoprostol is an anlogue PGE1, used in peroral pills.

The complication are very rare at aplication of mifepristone and misoprostole in the aim to the termination the early unwanted pregnancy. The appearance of more efficient procedure of drugs called out abortions, it does not mean taht decision for the abortion is more modest. The ease and safety should not help to make a decision.

Discovery of novel mifepristone derivatives via suppressing KLF5 expression for the treatment of triple-negative breast cancer

Triple-negative breast cancer (TNBC) is one of the most malignant breast cancers currently with a lack of targeted therapeutic drugs. Accumulating evidence supports that KLF5 represents a novel therapeutic target for the treatment of basal TNBC. Our previous studies revealed that mifepristone is capable of suppressing TNBC cell proliferation and promoting cancer cell apoptosis by inhibiting KLF5 expression. Nevertheless, its anticancer efficacy is only modest with high dose. Moreover, its main metabolite N-desmethyl mifepristone with the removal of one methyl moiety results in a significant loss of antiproliferative activity, indicating an important pharmacophore domain around this methyl moiety. To improve the pharmacokinetic properties including metabolic stability and enhance the anticancer activities, a focused compound library by altering this sensitive metabolic region of mifepristone has been designed and synthesized for scaffold repurposing and structural optimization. Compound 17 (FZU-00,004) has been identified with an attractive anticancer profile against TNBC via suppressing KLF5 expression.

Synthesis of metapristone through an efficient N-demethylation of mifepristone

An improved and efficient condition of N-demethylation of mifepristone in an excellent yield is described.

Early versus late misoprostol administration after mifepristone for medical abortion

PURPOSE

To evaluate the successful medical termination of pregnancy comparing two regimens: misoprostol 2 or 48 h after mifepristone administration.

DESIGN

Prospective randomized study.

SETTING

Department of Obstetrics and Gynecology.

SAMPLE

One hundred pregnant women admitted for medical termination of pregnancy were enrolled; no pregnancies were over 55 days gestational age.

METHODS

All subjects were randomly assigned for misoprostol administration either 2 or 48 h after mifepristone. All participants underwent transvaginal ultrasound examination for uterine contents 48 h and 3 weeks after mifepristone.

MAIN OUTCOME MEASURE

Procedure failure, defined as the presence of fetal heart activity, presence of a gestational sac, or a need for uterine curettage after misoprostol administration.

RESULTS

Each group consisted of 50 women. Fetal heart activity was significantly more frequent after 48 h in the 2-h interval group (10/50) than in the 48-h interval group (0/50) (p = 0.002). Three weeks after misoprostol administration, fetal heart activity was present in 4/50 (8 %) in the 2-h interval group (p = 0.118) and none of the 48-h interval group. At 48 h residual tissue was present in 13/50 (26 %) and 5/50 (10 %) in the 2 and 48-h interval groups, respectively (p = 0.031); this was reduced to 12/50 (24 %) compared to 5/50 (10 %) in the two groups, respectively (p = 0.054) after 3 weeks.

CONCLUSIONS

Successful medical termination of pregnancy can be achieved using misoprostol administration 2 h after mifepristone in 76 % of cases. However, this regimen is not recommended as it is significantly inferior to the traditional 48-h interval regimen.

Differential effects of sympathetic nervous system and hypothalamic-pituitary-adrenal axis on systemic immune cells after severe experimental stroke

Infectious complications are the leading cause of death in the post-acute phase of stroke. Post-stroke immunodeficiency is believed to result from neurohormonal dysregulation of the sympathetic nervous system (SNS) and hypothalamic-pituitary-adrenal (HPA) axis. However, the differential effects of these neuroendocrine systems on the peripheral immune cells are only partially understood. Here, we determined the impact of the hormones of the SNS and HPA on distinct immune cell populations and characterized their interactions after stroke. At various time points after cortical or extensive hemispheric cerebral ischemia, plasma cortisone, corticosterone, metanephrine and adrenocorticotropic hormone (ACTH) levels were measured in mice. Leukocyte subpopulations were flow cytometrically analyzed in spleen and blood. To investigate their differential sensitivity to stress hormones, splenocytes were incubated in vitro with prednisolone, epinephrine and their respective receptor blockers. Glucocorticoid receptor (GCR) and beta2-adrenergic receptor (β2-AR) on leukocyte subpopulations were quantified by flow cytometry. In vivo effects of GCR and selective β2-AR blockade, respectively, were defined on serum hormone concentrations, lymphopenia and interferon-γ production after severe ischemia. We found elevated cortisone, corticosterone and metanephrine levels and associated lymphocytopenia only after extensive brain infarction. Prednisolone resulted in a 5 times higher cell death rate of splenocytes than epinephrine in vitro. Prednisolone and epinephrine-induced leukocyte cell death was prevented by GCR and β2-AR blockade, respectively. In vivo, only GCR blockade prevented post ischemic lymphopenia whereas β2-AR preserved interferon-γ secretion by lymphocytes. GCR blockade increased metanephrine levels in vivo and prednisolone, in turn, decreased β2-AR expression on lymphocytes. In conclusion, mediators of the SNS and the HPA axis differentially affect the systemic immune system after stroke. Moreover, our findings suggest a negative-feedback of corticosteroids on the sympathetic axis which may control the post-stroke stress-reaction. This complex interplay between the HPA and the SNS after stroke has to be considered when targeting the neurohormonal systems in the post acute phase of severe stroke.

Effects of endogenous glucocorticoids on allergic inflammation and T(H)1 /T(H)2 balance in airway allergic disease

BACKGROUND

Glucocorticoids play an important role in modulating allergic inflammation and immune response. However, little is known about the role of endogenous glucocorticoids in airway allergic disease.

OBJECTIVE

To investigate the effects of endogenous glucocorticoids on regulating allergic inflammation and T(H)1/T(H)2 balance in an airway allergic murine model.

METHODS

An ovalbumin-sensitized murine model was established by intraperitoneal injection sensitization and intranasal challenge with ovalbumin. Glucocorticoid release was inhibited by administration of metyrapone, and the peripheral glucocorticoid receptors were blocked by administration of RU486. The numbers of eosinophils in the lung, peripheral blood, and bone marrow were quantified. The changes in T(H)2/T(H)1 cells were investigated by flow cytometry, and their cytokines were tested by enzyme-linked immunosorbent assay, including interleukin 4, interleukin 5, and interferon gamma, in the supernatant of the spleen cell culture.

RESULTS

Inhibition of endogenous glucocorticoids caused more sneezing and further increased eosinophil counts in the peripheral blood and bone marrow of the sensitized mice. However, by inhibition of endogenous glucocorticoids, the interferon gamma levels were upregulated, the interleukin 4 and 5 levels were down-regulated, and the ratio of T(H)2/T(H)1 cells decreased significantly, indicating a shift to a T(H)1-predominant immune response in sensitized mice.

CONCLUSIONS

Our findings suggest that endogenous glucocorticoids play an important role in abating allergic inflammatory reaction and modulating the T(H)1/T(H)2 balance in an airway allergic murine model. Inhibition of endogenous glucocorticoids resulted in a shift to T(H)1 predominance, but that did not attenuate the severity of the allergic inflammatory reaction.

Emergency contraception: a review

Emergency contraception (EC), also known as 'the morning after pill', or post-coital contraception, is a modality of preventing the establishment of a pregnancy after unprotected intercourse. Both a hormonal and an intrauterine form are available. Modern hormonal EC, with low side effects, was first proposed by Yuzpe in 1974. More recently, a new regimen, consisting of levonorgestrel administered alone, was introduced and found in clinical trials to be more effective (if taken as early as possible), and associated with less side effects than the Yuzpe regimen, which it has gradually replaced. The WHO developed another regimen based on the use of the selective progesterone receptor modulator (antiprogestin) mifepristone and conducted trials with different dosages. Intrauterine EC was first proposed by Lippes in 1976. It has the advantage of being applicable for almost a week and the disadvantage of a greater complexity. In addition, this modality is solely interceptive, acting by preventing implantation. Pregnancy rates reported following EC using an intrauterine device with more than 300 mm2 of copper are consistently low (0.1-0.2%).

Selective serotonin reuptake inhibitor and substance P antagonist enhancement of natural killer cell innate immunity in human immunodeficiency virus/acquired immunodeficiency syndrome

BACKGROUND

Natural killer (NK) cells play an important role in innate immunity and are involved in the host defense against human immunodeficiency virus (HIV) infection. This study examines the potential role of three underlying regulatory systems that have been under investigation in central nervous system research as well as immune and viral research: serotonin, neurokinin, and glucocorticoid systems.

METHODS

Fifty-one HIV-seropositive subjects were recruited to achieve a representative sample of depressed and nondepressed women. The effects of a selective serotonin reuptake inhibitor (SSRI), a substance P (SP) antagonist, and a glucocorticoid antagonist on NK cell function were assessed in a series of ex vivo experiments of peripheral blood mononuclear cells from each HIV-seropositive subject.

RESULTS

Natural killer cell cytolytic activity was significantly increased by the SSRI citalopram and by the substance P antagonist CP-96345 relative to control conditions; the glucocorticoid antagonist, RU486, showed no effect on NK cytotoxicity. Our results suggest that the effects of the three agents did not differ as a function of depression.

CONCLUSIONS

Our findings provide evidence that NK cell function in HIV infection may be enhanced by serotonin reuptake inhibition and by substance P antagonism. It remains to be determined if HIV-related impairment in not only NK cytolytic activity but also NK noncytolytic activity can be improved by an SSRI or an SP antagonist. Clinical studies are warranted to address these questions and the potential roles of serotonergic agents and SP antagonists in improving NK cell immunity, delaying HIV disease progression, and extending survival with HIV infection.

Mifepristone (RU 486) in Cushing's syndrome

CONTEXT

Mifepristone (RU 486) blocks the action of cortisol by binding to the glucocorticoid receptor and, therefore, is of potential therapeutic value in Cushing's syndrome. However, research in endogenous hypercortisolism has been hampered by the controversy related to the use of mifepristone for inducing abortion. Currently, new studies are planned to better define the role of RU 486 in Cushing's syndrome. This paper reviews the available evidence concerning the therapeutic effects and adverse events of RU 486 in Cushing's syndrome.

EVIDENCE ACQUISITION

Original articles and reviews were identified using a PubMed search strategy covering the time period until February 2007.

EVIDENCE SYNTHESIS

Treatment of Cushing's syndrome with mifepristone has been reported in a total of 18 patients, with daily doses ranging from 5 to 30 mg/kg. Case reports indicate that the mifepristone-induced receptor blockade may lead to significant clinical improvement in patients with Cushing's syndrome in whom surgery and inhibitors of adrenal steroidogenesis fail to control hypercortisolism. Due to its rapid onset of action, mifepristone may be particularly useful in acute crises, e.g. in cortisol-induced psychosis. Side effects include adrenal insufficiency and, as a result of its antiprogestin action, endometrial hyperplasia in long-term treatment. Adrenal insufficiency can be assessed only by careful clinical evaluation, as the hormonal parameters are not reliable during receptor blockade, and is rapidly reversed by exogenous dexamethasone. Well-designed larger clinical trials are needed to better assess the value of this interesting drug in the treatment of Cushing's syndrome.

Does glucocorticoid receptor blockade exacerbate tissue damage after mineralocorticoid/salt administration?

Mineralocorticoid receptor (MR) antagonism reverses established inflammation, oxidative stress, and cardiac fibrosis in the mineralocorticoid/salt-treated rat, whereas withdrawal of the mineralocorticoid deoxycorticosterone (DOC) alone does not. Glucocorticoid receptors (GRs) play a central role in regulating inflammatory responses but are also involved in cardiovascular homeostasis. Physiological glucocorticoids bind MR with high affinity, equivalent to that for aldosterone, but are normally prevented from activating MR by pre-receptor metabolism by 11beta-hydroxysteroid dehydrogenase 2. We have previously shown a continuing fibrotic and hypertrophic effect after DOC withdrawal, putatively mediated by activation of glucocorticoid/MR complexes; the present study investigates whether this effect is moderated by antiinflammatory effects mediated via GR. Uninephrectomized rats, drinking 0.9% saline solution, were treated as follows: control; DOC (20 mg/wk) for 4 wk; DOC for 4 wk and no steroid wk 5-8; DOC for 4 wk plus the MR antagonist eplerenone (50 mg/kg.d) wk 5-8; DOC for 4 wk plus the GR antagonist RU486 (2 mg/d) wk 5-8; and DOC for 4 wk plus RU486 and eplerenone for wk 5-8. After steroid withdrawal, mineralocorticoid/salt-induced cardiac hypertrophy is sustained, but not hypertension. Inflammation and fibrosis persist after DOC withdrawal, and GR blockade with RU486 has no effect on these responses. Rats receiving RU486 for wk 5-8 after DOC withdrawal showed marginal blood pressure elevation, whereas eplerenone alone or coadministered with RU486 reversed all DOC/salt-induced circulatory and cardiac pathology. Thus, sustained responses after mineralocorticoid withdrawal appear to be independent of GR signaling, in that blockade of endogenous antiinflammatory effects via GR does not lead to an increase in the severity of responses in the mineralocorticoid/salt-treated rat after steroid withdrawal.

Changes in the ovarian dynamics and endocrine profiles in goats treated with a progesterone antagonist during the early luteal phase of the estrous cycle

The aim of the present study was to determine the physiological role of endogenous progesterone in the regulation of ovarian dynamics, gonadotropin and progesterone secretion during the early luteal phase in the goat. Cycling Shiba goats received subcutaneously a vehicle (control group, n=5) or 50 mg of RU486 (RU486 group, n=4) daily from 1 to 7 days after ovulation (day 0) determined by transrectal ultrasonography. Ovarian dynamics were monitored by the ultrasonography and blood samples were collected daily until the subsequent ovulation for analysis of progesterone, luteinizing hormone (LH) and follicle stimulating hormone (FSH) secretion. Blood samples were also collected at 10 min intervals for 6 h on day 3 and day 7 for the analysis of pulsatile patterns of LH and FSH. The LH pulse frequency was significantly (P<0.05) higher in the RU486 group than in the control group on day 7 (4.8+/-1.1 pulses/6 h versus 1.2+/-0.4 pulses/6 h). The shape of the FSH pulses was unclear on day 3 and day 7 in both groups and the overall means of FSH concentration for 6 h on day 3 and day 7 were not significantly different between the RU486 and the control groups. The pattern of daily FSH concentrations showed a wave-like fluctuation in both groups. There was no significant difference in the inter-peak intervals of the wave-like pattern of daily FSH secretion between the RU486 and the control groups (4.1+/-0.6 days versus 4.5+/-0.6 days). The maximum diameter of the largest follicle that grew from day 1 to day 7 in the RU486 group tended to be greater than that in control goats (6.4+/-0.8 mm versus 5.0+/-0.8 mm, P=0.050), whereas no significant difference was detected in the size of the corpus luteum and progesterone concentrations between the control and RU486 groups on almost all days during the treatment period. These results indicate that the rise of the progesterone concentration suppresses the pulsatile LH secretion and follicular growth, whereas progesterone has no physiological role in the regulation of FSH secretion and luteal function during the early luteal phase of the estrous cycle in goats.

Contraception today

Modern contraceptive methods represent more than a technical advance: they are the instrument of a true social revolution-the "first reproductive revolution" in the history of humanity, an achievement of the second part of the 20th century, when modern, effective methods became available. Today a great diversity of techniques have been made available and-thanks to them, fertility rates have decreased from 5.1 in 1950 to 3.7 in 1990. As a consequence, the growth of human population that had more than tripled, from 1.8 to more than 6 billion in just one century, is today being brought under control. At the turn of the millennium, all over the world, more than 600 million married women are using contraception, with nearly 500 million in developing countries. Among married women, contraceptive use rose in all but two developing countries surveyed more than once since 1990. Among unmarried, sexually active women, it grew in 21 of 25 countries recently surveyed. Hormonal contraception, the best known method, first made available as a daily pill, can today be administered through seven different routes: intramuscularly, intranasally, intrauterus, intravaginally, orally, subcutaneously, and transdermally. In the field of oral contraception, new strategies include further dose reduction, the synthesis of new active molecules, and new administration schedules. A new minipill (progestin-only preparation) containing desogestrel has been recently marketed in a number of countries and is capable of consistently inhibiting ovulation in most women. New contraceptive rings to be inserted in the vagina offer a novel approach by providing a sustained release of steroids and low failure rates. The transdermal route for delivering contraceptive steroids is now established via a contraceptive patch, a spray, or a gel. The intramuscular route has also seen new products with the marketing of improved monthly injectable preparations containing an estrogen and a progestin. After the first device capable of delivering progesterone directly into the uterus was withdrawn, a new system releasing locally 20 microg evonorgestrel is today marketed in a majority of countries with excellent contraceptive and therapeutic performance. Finally, several subcutaneously implanted systems have been developed: contraceptive "rods," where the polymeric matrix is mixed with the steroid and "capsules" made of a hollow polymer tube filled with free steroid crystals. New advances have also been made in nonhormonal intrauterine contraception with the development of "frameless" devices. The HIV/AIDS pandemic forced policy makers to look for ways to protect young people from sexually transmitted diseases as well as from untimely pregnancies. This led to the development of the so-called dual protection method, involving the use of a physical barrier (condom) as well as that of a second, highly effective contraceptive method. More complex is the situation with antifertility vaccines, still at a preliminary stage of development and unlikely to be in widespread use for years to come. Last, but not least, work is in progress to provide effective emergency contraception after an unprotected intercourse. Very promising in this area is the use of selective progesterone receptor modulators (antiprogestins).

Mid-trimester induced abortion: a review

Mid-trimester abortion constitutes 10-15% of all induced abortion. The aim of this article is to provide a review of the current literature of mid-trimester methods of abortion with respect to efficacy, side effects and acceptability. There have been continuing efforts to improve the abortion technology in terms of effectiveness, technical ease of performance, acceptability and reduction of side effects and complications. During the last decade, medical methods for mid-trimester induced abortion have shown a considerable development and have become safe and more accessible. The combination of mifepristone and misoprostol is now an established and highly effective method for termination of pregnancy (TOP). Advantages and disadvantages of medical versus surgical methods are discussed. Randomized studies are lacking, and more studies on pain treatment and the safety of any method used in patients with a previous uterine scar are debated, and data are scarce. Pain management in abortion requires special attention. This review highlights the need for randomized studies to set guidelines for mid-trimester abortion methods in terms of safety and acceptability as well as for better analgesic regimens.

Review of medical abortion using mifepristone in combination with a prostaglandin analogue

Induced abortion is still a major health problem in the world and the most frequently performed intervention in obstetrics and gynecology with an estimated total of 46 million worldwide each year. Medical abortion with mifepristone and prostaglandin was first introduced in 1988 and is now approved in 31 countries. This combination of drugs has recently been included in the List of Essential Medicines by the World Health Organisation. The present review summarizes the development, physiology and the development of the currently used regimens.

Effect of intermittent treatment with mifepristone on bleeding patterns in Norplant® implant users

A double-blind, placebo-controlled, randomized trial, was carried out in 120 Norplant users to evaluate the effect of mifepristone, 100 mg/day administered for 2 consecutive days every 30 days, on the vaginal bleeding pattern. Treatment was given from months 2-7 of implant use. Volunteers recorded bleeding and spotting days, during treatment and for the ensuing 6-month period. During treatment, women on mifepristone recorded the same frequency of bleeding/spotting episodes but significantly less prolonged bleeding episodes than placebo controls (mean +/- SD: 11 +/- 3 vs. 22 +/- 23 days) and their total number of bleeding days was 35% lower than in the placebo group. After the end of mifepristone use, bleeding patterns were similar in both groups. One pregnancy occurred in the mifepristone-treated group, in month 6 of treatment, the outcome was a healthy male baby. We conclude that intermittent administration of mifepristone can offer a clinically significant improvement of the vaginal bleeding pattern in Norplant users.

Emergency contraception--clinical and ethical aspects

Emergency contraception (EC) consists of either 1.5 mg of levonorgestrel (LNG) in one or two doses, or a combination of LNG with ethinylestradiol, administered for up to 5 days after unprotected intercourse. Clinical studies indicate that LNG alone is more effective and has less side effects. Its effectiveness decreases the longer after coitus it is taken. EC is indicated when there is non-compliance or accidents with the use of regular methods of contraception, or when women have had voluntary or imposed unprotected intercourse. The ethics of providing EC has been questioned by some, arguing that it acts by preventing implantation. Scientific evidence does not support this concept, but shows that EC acts mostly before fertilization. Placing obstacles to the access of EC is unethical as it transgresses the ethical principles of autonomy, non-maleficence beneficence and justice. Far from inducing abortions, EC reduces unwanted pregnancies and prevents abortion.

Effects of onapristone on postmenopausal endometrium

The progesterone antagonist mifepristone (RU486, Exelgyn) has been shown to exert a paradoxical agonist effect on postmenopausal endometrium. We conducted a study to investigate the effects of the 'pure' antiprogestin onapristone (ZK 98 299, Schering AG) on postmenopausal endometrium. Seventeen postmenopausal subjects (45-62 years), took 2 mg of oestradiol and either placebo, 1 mg onapristone or 10 mg of onapristone, daily for 56 days. An endometrial biopsy was performed during the final week of treatment and assessed for histology and immunohistochemistry for oestrogen receptors (ER), progesterone (PR), androgen receptors (AR) and the cell proliferation marker Ki 67. FSH fell in all 14 subjects who completed the study, consistent with the effect of oestradiol treatment. There was a dose-dependent additive effect of onapristone on suppression of gonadotrophins. All endometrial biopsies showed proliferative endometrium. A similar pattern and intensity of immunostaining of ER, PR and Ki 67 was observed in all groups, with positive immunoreactivity in both glands and stroma. AR immunostaining was observed in both glands and stroma from all subjects, but there was an increase in intensity of immunostaining within the glandular epithelium of women receiving 10 mg onapristone. The antiprogestin onapristone, in contrast to mifepristone, is not agonistic on postmenopausal endometrium and does not exert obvious antiproliferative effects. It does however cause a dose dependent suppression of FSH and LH release.

Effect of chronic administration of selective glucocorticoid receptor antagonists on the rat hypothalamic-pituitary-adrenocortical axis

The effects of the selective glucocorticoid receptor (GR) antagonists ORG 34850, ORG 34116, and ORG 34517 on the rat hypothalamic-pituitary-adrenocortical (HPA) system were investigated. To assess the potency of the compounds to occupy GR in the brain and pituitary, we applied a single acute subcutaneous (s.c.) injection (10 mg/kg). ORG 34517 was most potent to occupy GR in the anterior pituitary and distinct brain areas, whereas all compounds were unable to occupy mineralocorticoid receptor (MR). Chronic administration of ORG 34850, ORG 34116, and ORG 34517 (20 mg/kg/day) for 1, 3, and 5 weeks resulted only in minor changes in brain GR levels. However, profound increases of hippocampal MR were observed virtually at all time points. Treatment with ORG 34850 and ORG 34116 elicited episodic increases in HPA axis activity, whereas ORG 34517 did not cause any changes in HPA activity. Thus, the GR antagonists exert distinct effects on the HPA axis, which may be pertinent for the proposed antidepressant activity of these compounds.

Pharmacokinetics and metabolism of endothelin receptor antagonist: contribution of kidneys in the overall in vivo N-demethylation

In vivo clearance of BMS-182874 was primarily due to metabolism via stepwise N-demethylation. Despite in vivo clearance approached ca 50% of the total liver plasma flow, BMS-182874 was completely bioavailable after oral administration in rats. Saturable first-pass metabolism and the role of extrahepatic tissue were evaluated as possible reasons for complete oral bioavailability despite extensive metabolic clearance. Pharmacokinetic parameters were obtained after an intravenous and a range of oral doses of BMS-182874 in rats. Bile and urine were collected from bile-duct cannulated (BDC) rats and the in vivo metabolic pathways of BMS-182874 were evaluated. Pharmacokinetics of BMS-182874 were also compared in nephrectomized (renally impaired) vs. sham-operated control rats. Oral bioavailability of BMS-182874 averaged 100%, indicating that BMS-182874 was completely absorbed and the first-pass metabolism (liver or intestine) was negligible. The AUC and Cmax values increased dose-proportionally, indicating kinetics were linear within the oral dose range of 13 to 290 mmole/kg. After intravenous administration of BMS-182874 to BDC rats, about 2% of intact BMS-182874 was recovered in excreta, indicating that BMS-182874 was cleared primarily via metabolism in vivo. The major metabolite circulating in plasma was the mono-N-desmethyl metabolite and the major metabolite recovered in excreta was the di-N-desmethyl metabolite. In vivo clearance of BMS-182874 was significantly reduced in nephrectomized rats. These observations suggest saturable first-pass metabolism is unlikely to be a mechanism for complete oral bioavailability of BMS-182874. Reduced clearance observed in the nephrectomized rats suggests that extrahepatic tissues (e.g., kidneys) may play an important role in the in vivo clearance of xenobiotics that are metabolized via N-demethylation.

Mifepristone followed on the same day by vaginal misoprostol for early abortion

We performed a pilot study to examine the clinical efficacy of mifepristone 200 mg followed on the same day by misoprostol 800 microg vaginally in women with pregnancies up to 49 days gestation. Forty women received mifepristone 200 mg after which they self-inserted misoprostol intravaginally 6 to 8 h later at home. Participants returned for an evaluation, including transvaginal ultrasonography, 24 +/- 1 h after using the misoprostol. Participants who had not aborted received a second dose of misoprostol to administer 48 h after the mifepristone. All participants returned approximately 2 weeks after receiving mifepristone. At 24 h after receiving misoprostol, 37/40 (92%, 95% CI 81-98%) had ultrasonographic evidence of complete abortion. By follow-up 2 weeks after the mifepristone, 40/40 (100%, 95% CI 92-100%) women were felt to have complete abortions. One subject subsequently had a suction aspiration for an incomplete abortion on study Day 44. Nausea, vomiting, diarrhea, and warmth/chills occurred in 38%, 13%, 13%, and 60%, respectively. This pilot study suggests that mifepristone 200 mg, followed on the same day by misoprostol 800 microg vaginally, effects abortion at rates comparable to regimens using the standard time interval of 48 h between medications.

Mifepristone

OBJECTIVE

To review the efficacy and safety of mifepristone (with misoprostol) for the termination of early pregnancy.

DATA SOURCES

A MEDLINE search (1966-October 2000) was conducted, and additional references listed in articles were included; unpublished data obtained from the manufacturer were used to identify data from the scientific literature. Studies evaluating mifepristone were considered for inclusion.

STUDY SELECTION

Human clinical studies in the English language were reviewed and evaluated. Clinical trials selected for detailed review were limited to those including the regimens of mifepristone and misoprostol, recently approved by the Food and Drug Administration for early pregnancy termination.

DATA SYNTHESIS

Mifepristone is an antiprogestin available for pregnancy termination in combination with a prostaglandin such as misoprostol. Mifepristone offers efficacy similar to, if not better than, other drugs used for pregnancy termination, but appears less efficacious overall than surgical termination of pregnancy. Mifepristone in combination with misoprostol commonly causes adverse effects such as abdominal pain and, less commonly, can cause serious adverse effects such as incomplete abortion; endometritis; and bleeding warranting transfusion, hospitalization, or surgery. Mifepristone is metabolized by the cytochrome P450 system. Thus, the potential for drug interactions with this agent exists, although this has not been well studied. Data are included from clinical trials evaluating the safety, tolerability, efficacy, and pharmacoeconomics of mifepristone combined with misoprostol for early pregnancy termination. Data comparing the use of these agents with surgical abortion and other drugs used for pregnancy termination are included where available.

CONCLUSIONS

Mifepristone in combination with misoprostol for the termination of early pregnancy (amenorrhea of < or = 49 d) is effective in 92-95% of women. Incomplete abortion requiring surgical abortion after the fact occurs in 3-5% of women, and pregnancy continues 1-2% of the time. Mifepristone with misoprostol treatment is not without significant risks, including hemorrhage, infection, and potential for long-term emotional consequences.

The progesterone blockade of the luteinizing hormone surge is overcome by RU486

Progesterone can prevent the oestrogen-induced and spontaneous preovulatory luteinizing hormone (LH) surges but the mechanisms underlying this effect remain poorly understood. Using a follicular phase ovariectomised (OVX) ewe model and by elevating progesterone in the presence of oestrogen to inhibit the LH surge, we investigated whether the progesterone receptor antagonist, RU486, could block the inhibitory effects of progesterone. Accordingly, intravaginal progesterone implants were inserted into OVX Ile-de-France ewes (n = 18), bearing 10 mm Silastic 17beta-oestradiol implants. Ten days later, the progesterone implants were removed, whereupon new implants were inserted immediately into 12 ewes: six of which were also injected with 100 mg RU486 dissolved in 10 mL vehicle (10% alcohol in peanut oil) and six received vehicle only. The remaining six ewes were injected with vehicle only. RU486 and vehicle injections were made again 12 and 24 h later. After the last injection, oestrogen concentrations were raised to peak follicular phase levels in all ewes by subcutaneous insertion of four 3-cm 17beta-oestradiol implants. Blood samples were collected every 2 h for 40 h starting 9 h after the insertion of the oestrogen implants. As expected, the six ewes treated only with oestradiol had a LH surge whereas no ewes given the implants in the presence of progesterone surged. RU486 completely blocked the inhibitory effect of progesterone. There were no differences in the time of LH surge onset, duration over which LH levels remained above their half-maximal concentration or magnitude of the LH surge between the two groups showing surges. Our study suggests strongly that the progesterone-mediated blockade of the ovine oestrogen-induced LH surge is not through allopregnanolone activation of the GABA(A) receptor. Rather, our study demonstrates that this effect is transduced by the classic nuclear progesterone receptor.

Safety, tolerability, and pharmacokinetics of a novel, selective antiprogestagen (Org 31710) in healthy male volunteers

The safety and tolerability as well as pharmacokinetics of a new selective antiprogestagen, Org 31710, were studied after oral administration of single doses of 10, 25, 50, or 75 mg to 24 healthy male volunteers. Per dose-group, five subjects received active and one subject received placebo treatment. In subjects receiving 75 mg, the effects of Org 31710 on serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone were also studied. No adverse or seriously adverse events were observed. All doses of Org 31710 were well tolerated. Characterization of the Org 31710 plasma pharmacokinetics revealed a statistically significant deviation from linearity: the dose normalized Cmax (nCmax) and dose normalized area under the curve (nAUC) values were significantly lower for the higher dosages (p < 0.05). Furthermore, tmax tended to decrease (from 1.6 to 0.9 h), whereas the elimination half-life (t1/2) tended to increase (from on average 45 to 57 h) with increasing dose. Org 31710 did not have any effect on serum levels of FSH, LH, and testosterone. In conclusion, Org 31710 appears to be a safe and well-tolerated compound in the dosage range studied.

Effects and metabolism of steroid hormones in human neuroblastoma cells

The development of the central nervous system is influenced by sex steroids and by their metabolites. However, little information on the possible effects of steroid hormones on neuroblastoma cells is available. Human neuroblastoma cell lines have been used as a model of human neuroblasts in vitro to study the metabolism of steroid hormones; in addition, the effects of steroids and steroid antagonists on neuroblastoma cell growth have also been investigated. The results obtained show that SH-SY5Y human neuroblastoma cells may actively metabolize testosterone and progesterone to their respective 5 alpha-reduced metabolites and that differentiation of neuroblastoma cells is paralleled by a significant increase in expression of the type-1 5 alpha-reductase and of the formation of steroid metabolites. All these data are suggestive of a potential role of steroid 5 alpha-reduced metabolites in the biology of neuroblastoma cells. Studies performed to analyze the role of steroid hormones on neuroblastoma cell proliferation show that progesterone at low doses may induce minor stimulation, and at higher doses, a toxic effect on the neuroblastoma cell line SK-N-SH is seen. Moreover, the antiprogestin 17 beta-hydroxy-11 beta-(4-dimethylamino-phenyl-1)-17-(prop-1-ynyl)estra-4,9-dien+ ++-3-one (RU486) decreases the proliferation of these cells in a dose-dependent manner. The effect of RU486 is not antagonized by either progesterone or dexamethasone, a result that seems to exclude the action of RU486 via classic intracellular steroid hormone receptors.

Antiprogestin-mediated inactivation of cytochrome P450 3A4

Based on previous observations of very short periods of linearity for antiprogestin metabolite formation and the presence of a common tertiary amine moiety in each compound as the principal site of their metabolism, we hypothesized that mifepristone, lilopristone and onapristone are oxidized by cytochrome P450 (CYP) 3A4 to reactive nitroso species that complex the heme of the enzyme, thereby inactivating it. Upon preincubation with human liver microsomes in the presence (but not the absence) of NADPH, mifepristone inhibited midazolam 1'-hydroxylation, a marker of CYP3A4 catalytic activity, very potently (IC50 approximately 3.5 mumol/l) and extensively (by approximately 87%). Lilopristone and onapristone also displayed NADPH and time-dependent inactivation of CYP3A4 with characteristics very similar to mifepristone. These data support antiprogestin-mediated inactivation of CYP3A4 and suggest the potential for drug-drug interactions and time-dependent nonlinearities in pharmacokinetics upon their long-term administration.

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.

Antiprogestin pharmacodynamics, pharmacokinetics, and metabolism: implications for their long-term use

Antiprogestins represent a relatively new and promising class of therapeutic agents that could have significant impact on human health and reproduction. In the present work, the pharmacodynamics, pharmacokinetics, and metabolism of mifepristone (MIF), lilopristone (LIL), and onapristone (ONA) in humans are reviewed, and characteristics bearing important clinical implications are discussed. Although MIF has gained notoriety as an "abortion pill," antiprogestins may more importantly prove effective in the treatment of endometriosis, uterine leiomyoma, meningioma, cancers of the breast and prostate, and as contraceptive agents. MIF pharmacokinetics display nonlinearities associated with saturable plasma protein (alpha 1-acid glycoprotein, AAG) binding and characterized by lack of dose dependency for parent drug plasma concentrations (for doses greater than 100 mg) and a zero-order phase of elimination. LIL and ONA pharmacokinetics are less well characterized but ONA does not appear to bind AAG and displays a much shorter t1/2 than the other agents. The three antiprogestins are substrates of cytochrome P450 (CYP) 3A4, an enzyme exceedingly important in human xenobiotic metabolism. Even more implicative of likely drug-drug interactions subsequent to their long-term administration are recent data from our laboratory indicating that they inactivate CYP3A4 in a cofactor- and time-dependent manner, suggesting that complexation and induction of the enzyme may occur in vivo via protein stabilization. Moreover, it has been demonstrated that MIF increases CYP3A4 mRNA levels in human hepatocytes in primary culture, indicative of message stabilization and/or transcriptional activation of CYP3A4 expression. Finally, MIF has also been shown to inhibit P-glycoprotein function. Whether LIL and ONA share these latter two characteristics with MIF has not yet been determined but they illustrate properties that, in addition to diminished antiglucocorticoid activities and altered pharmacokinetic characteristics, warrant consideration during the development of these and never antiprogestational agents.

Glucocorticoid receptor regulates expression of L-selectin and CD11/CD18 on human neutrophils

BACKGROUND

Recent studies have raised the hypothesis that glucocorticoids could diminish the ability of endothelial cells to direct leukocyte traffic into inflamed tissues by inhibiting expression of the adhesion molecules endothelial-leukocyte adhesion molecule-1 and intercellular adhesion molecule-1. The aim of the present study was to investigate whether glucocorticoids also regulate the expression of L-selectin and CD11/CD18 integrins on human neutrophil granulocytes.

METHODS AND RESULTS

Incubation of human whole blood with platelet-activating factor (PAF, 1 mumol/L) evoked downregulation of L-selectin and upregulation of CD11/CD18 adhesion receptors on neutrophils as measured by flow cytometry. While dexamethasone (0.1 nmol/L to 100 mumol/L) did not affect expression of adhesion molecules on resting neutrophils, it attenuated the PAF-induced changes in L-selectin and CD18 expression in a time- and concentration-dependent fashion with IC50 values of 31 and 13 nmol/L, respectively. These effects of dexamethasone were completely aborted by RU-486 (10 mumol/L), which blocks transcriptional activation of the glucocorticoid receptor, and by the protein synthesis inhibitor cycloheximide (35.5 mumol/L). Dexamethasone, up to a concentration of 1 mumol/L, neither affected significantly the release of granule enzymes nor interfered with PAF binding to its membrane receptors.

CONCLUSIONS

Our results show that glucocorticoids at clinically relevant concentrations exert specific actions on expression of adhesion molecules on activated neutrophils, which are mediated through ligation of glucocorticoid receptors and induction of protein synthesis, and suggest a novel mechanism by which anti-inflammatory corticosteroids may inhibit leukocyte accumulation.

Protection against oxidative stress-induced neuronal cell death--a novel role for RU486

Free radicals and oxidative stress-induced neuronal cell death have been implicated in a variety of neurological disorders. Therefore, neuroprotection is of primary interest in basic and preclinical neuroscience. Here it is shown that RU486 (mifepristone), a potent antagonist of progesterone and glucocorticoid receptors, protects rat primary hippocampal neurons, clonal mouse hippocampal cells and organotypic hippocampal slice cultures against oxidative stress-induced neuronal cell death. 10(-5) M RU486 prevents intracellular peroxide accumulation and cell death induced by amyloid beta protein, hydrogen peroxide and glutamate, neurotoxins that have been implicated in certain neurodegenerative disorders, including Alzheimer's disease. RU486 has a significant protective effect that is independent of the presence and activation of glucocorticoid or progesterone receptors. The neuroprotective activity of this well-studied drug may have an impact on therapeutic interventions for neurodegenerative conditions which involve peroxidation processes, such as stroke and Alzheimer's disease.

Determination of RU486 (mifepristone) in blood by radioreceptorassay; a pharmacokinetic study

A human progesterone receptor assay has been developed for the measurement of the biologically active molecular fraction of RU486 (RU486 binding equivalent) for studying its pharmacokinetic properties. Thirty-nine healthy pregnant volunteers with amenorrhoea of 49 days or less receiving a single oral dose of 200 mg, 400 mg or 600 mg RU486 orally in a single dose were involved in this study. Blood samples were collected within 48 hours for the analysis. It was found that the pharmacokinetics of the RU486 binding equivalent followed an open two-compartment model. The dose was rapidly absorbed and peak serum concentrations were measured within 1-2 hours after ingestion of the drug. The distribution was also rapid, but the elimination was slow, the elimination half-life ranging between 83 and 90 hours. Significant differences were found between the peak plasma values for the 200 mg and 600 mg doses (p < 0.05) and between the AUCs for the 200 mg and 600 mg doses (p < 0.01) and the 400 mg and 600 mg doses (p < 0.05). It can be concluded that this newly developed radioreceptor assay satisfies the requirements of radioligand binding techniques and can be used to determine the serum levels of RU486 and its metabolites, which are able to bind to human myometrial progesterone receptors. The pharmacokinetics for the RU486 binding equivalent is similar to that for RU486, with the exception of very slow elimination, which may originate from the measurement of the biologically active metabolites together with the parent compound.

Muscle hypercatabolism during cancer cachexia is not reversed by the glucocorticoid receptor antagonist RU38486

In rats into which a fast growing ascites hepatoma (Yoshida AH-130) had been transplanted, tumor growth elicited a marked loss of body weight and tissue waste, particularly of the skeletal muscle. This depletion has been associated with enhanced rates of protein breakdown, mainly due to hyperactivation of the ATP-ubiquitin-dependent proteolytic system [Llovera, M., García-Martínez, C., Agell, N., Marzábal, M., López-Soriano, F.J. and Argilés, J.M. (1994) FEBS Lett., 338, 311-318]. Profound alterations of the hormonal status and the production of tumor necrosis factor have been involved in the development of such wasting syndrome [Tessitore, L., Costelli, P. and Baccino, F.M. (1993) Br. J. Cancer, 67, 15-23]. In the present study, the role of glucocorticoids in muscle hypercatabolism was investigated using the glucocorticoid receptor antagonist RU38486. The treatment with this drug was unable to interfere with the development of cachexia in the AH-130 hosts with regard to tissue weight as well as to muscle protein turnover rates. As one would expect, the RU38486 was also ineffective in lowering both the expression of ubiquitin mRNA and the degree of muscle protein ubiquitinization in AH-130 bearers. These data allow us to exclude that glucocorticoids play a direct crucial role in the development of cachexia in this tumor model.