Induction of ovulation with clomiphene citrate

Amoxicillin-resistant Streptococcus pneumoniae can be resensitized by targeting the mevalonate pathway as indicated by sCRilecs-seq

Antibiotic resistance in the important opportunistic human pathogen Streptococcus pneumoniae is on the rise. This is particularly problematic in the case of the β-lactam antibiotic amoxicillin, which is the first-line therapy. It is therefore crucial to uncover targets that would kill or resensitize amoxicillin-resistant pneumococci. To do so, we developed a genome-wide, single-cell based, gene silencing screen using CRISPR interference called sCRilecs-seq (subsets of CRISPR interference libraries extracted by fluorescence activated cell sorting coupled to next generation sequencing). Since amoxicillin affects growth and division, sCRilecs-seq was used to identify targets that are responsible for maintaining proper cell size. Our screen revealed that downregulation of the mevalonate pathway leads to extensive cell elongation. Further investigation into this phenotype indicates that it is caused by a reduced availability of cell wall precursors at the site of cell wall synthesis due to a limitation in the production of undecaprenyl phosphate (Und-P), the lipid carrier that is responsible for transporting these precursors across the cell membrane. The data suggest that, whereas peptidoglycan synthesis continues even with reduced Und-P levels, cell constriction is specifically halted. We successfully exploited this knowledge to create a combination treatment strategy where the FDA-approved drug clomiphene, an inhibitor of Und-P synthesis, is paired up with amoxicillin. Our results show that clomiphene potentiates the antimicrobial activity of amoxicillin and that combination therapy resensitizes amoxicillin-resistant S. pneumoniae. These findings could provide a starting point to develop a solution for the increasing amount of hard-to-treat amoxicillin-resistant pneumococcal infections.

Estrogen Receptors and Signaling in Fibroids: Role in Pathobiology and Therapeutic Implications

Uterine fibroids are the most common gynecologic tumors with a significant medical and financial burden. Several genetic, hormonal, and biological factors have been shown to contribute to the development and growth of fibroid tumors. Of these factors, estrogen is particularly critical since fibroids are considered estrogen dependent because no prepubertal cases have been described in the literature and tumors tend to regress after menopause. Understanding the role of estrogen in fibroids is not only important for understanding the pathobiology of fibroids but also for the development of successful therapeutics. In this review, we discuss the types and structure of estrogen receptors (nuclear and membrane bound, including α and β receptors and G protein-coupled estrogen receptor 1 GPER1). Estrogen-signaling pathways in fibroids include genomic (direct and indirect) and nongenomic including Ras-Raf-MEK (MAPK/Erk Kinase)-mitogen-activated protein kinase (MAPK) and phosphatidylinositide 3-kinase (PI3K)-phosphatidylinositol-3,4,5-trisphosphate (PIP3)-Akt (Protein kinase B)-mammalian target of rapamycin (mTOR) pathways; shortly Ras-Raf-MEK-MAPK and PI3K-PIP3-Akt-mTOR pathways. Several aberrations in estrogen receptors and signaling pathways are implicated in fibroid pathobiology. Current therapeutic and research agents targeting ERs/signaling include gonadotropin-releasing hormone (GnRH) agonists, GnRH antagonists, aromatase inhibitors, selective ER modulators, gene therapy, and others. Future research can identify potential targets for the development of novel treatments. In particular, epigenomics of estrogen activity and individualized (precision) medicine appear to be attractive areas for future research.

Structure-activity relationships of SERMs optimized for uterine antagonism and ovarian safety

Structure-activity relationship studies are described, which led to the discovery of novel selective estrogen receptor modulators (SERMs) for the potential treatment of uterine fibroids. The SAR studies focused on limiting brain exposure and were guided by computational properties. Compounds with limited impact on the HPO axis were selected using serum estrogen levels as a biomarker for ovarian stimulation.

A new selective estrogen receptor modulator with potent uterine antagonist activity, agonist activity in bone, and minimal ovarian stimulation

The use of selective estrogen receptor modulators for the treatment of estrogen-dependent diseases in premenopausal women has been hindered by undesirable ovarian stimulation and associated risks of ovarian cysts. We have identified a selective estrogen receptor modulator compound (LY2066948) that is a strong estrogen antagonist in the uterus yet has minimal effects on the ovaries of rats. LY2066948 binds with high affinity to both estrogen receptors and has potent estrogen antagonist activity in human uterine and breast cancer cells. Oral administration of LY2066948 to immature rats blocked uterine weight gain induced by ethynyl estradiol with an ED50 of 0.07 mg/kg. Studies in mature rats demonstrated that LY2066948 decreases uterine weight by 51% after 35 d treatment, confirming potent uterine antagonist activity over several estrous cycles. This strong uterine response contrasted with the minimal effects on the ovaries: serum estradiol levels remained within the normal range, whereas histologic evaluation showed granulosa cell hyperplasia in few of the rats. Bone studies demonstrated that LY2066948 prevented ovariectomy-induced bone loss and treatment of ovary-intact rats caused no bone loss, confirming estrogen receptor agonist skeletal effects. Collectively, these data show that LY2066948 exhibits a tissue-specific profile consistent with strong antagonist activity in the uterus, agonist activity in bone, and minimal effects in the ovaries.

Use of alternative therapies in menopause

Hormone replacement therapy has traditionally been used to treat the accompanying symptoms of oestrogen deficiency in menopause. However, not all women can, or prefer to, receive this treatment and alternatives should be considered to reduce the increased risk of osteoporosis and heart disease in menopausal women. This chapter reviews the current literature on the efficacy of phyto-oestrogens in preventing cardiovascular disease, various cancers and osteoporosis, as well as treating the vasomotor and other menopause-related symptoms. Select herbal therapies, as well as selective oestrogen receptor modulators, are also considered.

Antioestrogenic effect of trans-dehydrocrotonin, a nor-clerodane diterpene from Croton cajucara Benth. in rats

This study examined trans-dehydrocrotonin (t-DCTN), a nor-clerodane diterpene isolated from the Brazilian medicinal plant Croton cajucara Benth., for a possible antioestrogenic activity using immature rats as a model system for bioassay of oestrogen, and for an antiimplantation effect in regularly cycling rats of proven fertility. In the antioestrogen test, t-DCTN (25 and 50 mg/kg) effectively prevented oestrogen-induced increases of uterine wet weights. In addition, the vaginal openings provoked by oestrogen were completely prevented by t-DCTN. However, blastocyst-implantation was only insignificantly affected in t-DCTN pretreated animals. These results suggest that t-DCTN may be an antioestrogen and warrants further studies with regard to its mechanism of action.

Targeted Antiestrogens to Prevent Breast Cancer

Tamoxifen, the first selective estrogen receptor modulator (SERM), has provided invaluable laboratory and clinical evidence that such drugs can reduce the risk of breast cancer and increase bone density. Raloxifene is available for the prevention of osteoporosis, and preliminary studies show a decrease in breast cancer risk. On the basis of current information about the pharmacology of SERMs, a large breast cancer prevention trial called study of tamoxifen and raloxifene (STAR) has started in the USA. Results should be available in the next seven years.

Vulnerability of the endocrine system to xenobiotic influence

Natural sex hormones are most important factors guaranteeing the homeostasis of male and female sexual functions, including sexual differentiation and reproduction. Main target tissues include bone and skin, cardiovascular system, and possibly central nervous and immune systems. In medicine, synthetic hormonal substances with agonistic and antagonistic properties have been widely used for decades. Therapeutic benefit is the aim, and the many possibilities to interfere with normal or pathological hormonal situations are rather well understood. Synthetic hormonal agonists or (partial) antagonists may exhibit specific affinities to special receptors resulting in a spectrum of organotropies, or they may even induce opposite actions on different targets. Although not a new issue, environmental substances mimicking potentials of sex hormones have recently gained increased attention. There is not need to reinvent the wheel, since most (adverse) effects may be revealed with today's routine procedures used for testing medicinal substances, but some additional testing strategies should be included. Adverse effects of ecohormones may preferentially affect systems other than the human organism (assuming lower exposure and possibly lower susceptibility). Nevertheless, this survey is confined to possible alterations in the mammalian organism, since such effects are best understood from numerous experimental studies and clinical trials.

Modulation of the hepatic expression of the estrogen-regulated mRNA stabilizing factor by estrogenic and antiestrogenic nonsteroidal xenobiotics

Estrogen-mediated accumulation of apolipoprotein II (apoII) mRNA in the avian liver is due, in part, to its stabilization. This stabilization appears to be due to the estrogen-regulated mRNA stabilizing factor (E-RmRNASF) that is expressed in response to estrogen. The E-RmRNASF protects the mRNA from targeted endonucleolytic degradation (Ratnasabapathy, Cell Mol Biol Res 41: 583-594, 1995). To determine whether certain environmental xenobiotics altered the expression of the gene encoding E-RmRNASF by mimicking estrogen, roosters were given estrogen, tamoxifen, clomiphene, hexachlorophene, lindane, rotenone, chlordecone, dichlorodiphenyltrichloroethane (DDT); Araclor, methoxychlor, dieldrin, toxaphene, or bisphenol-A parenterally. Uniformly radiolabeled, capped, and polyadenylated apoII mRNA, incubated in vitro in the presence of liver cytosolic extracts from birds that received estrogen, tamoxifen, hexachlorophene, chlordecone, or Araclor, remained stable, indicating that these agents were estrogenic and stimulated the expression of E-RmRNASF. However, the same mRNA was degraded in similar extracts from control roosters and those treated with clomiphene, DDT, methoxychlor, dieldrin, rotenone, toxaphene, lindane, or bisphenol-A. To determine whether the latter agents were antiestrogenic, roosters were given a 1:5 molar combination of estrogen and each of the xenobiotics. ApoII mRNA showed degradation in liver extracts from roosters that received clomiphene, toxaphene, or bisphenol-A, indicating that these agents prevented estrogenic stimulation of expression of the E-RmRNASF and were antiestrogenic. However, the rest of the xenobiotics failed to antagonize estrogenic stimulation of E-RmRNASF gene expression. These results set a precedent in showing the estrogenic and antiestrogenic effects in vivo of environmental xenobiotics on the expression of a regulatory protein involved in estrogen-mediated mRNA stabilization.

Surgically induced ovulation in the polycystic ovary syndrome: wedge resection revisited in the age of laparoscopy

OBJECTIVE

To provide an up-to-date comprehensive review of published data on laparoscopic methods of ovulation induction in the polycystic ovary syndrome (PCOS). Areas to be considered include the historical background of these procedures, their outcomes as reported in the literature, and their potential adverse effects. Through the careful review of these issues, some recommendations for clinical use and further study are offered.

DESIGN

Relevant studies were identified through a the search of a computerized bibliographic database of holdings in the National Library of Medicine as well as the manual scanning and cross-referencing of relevant medical journals.

RESULTS

Twenty-nine relevant studies were identified in the English language literature. These studies consist almost exclusively of uncontrolled case series. Pregnancies after laparoscopic ovulation induction procedures have been reported in an average of 55% of treated subjects (range 20% to 65%). Potential advantages of laparoscopic ovulation induction over gonadotropin therapy may include possible cost savings, serial repetitive ovulatory events resulting from a single treatment, no increased risk of ovarian hyperstimulation or multiple gestation, and the prospect for a higher live birth rate owing to a seemingly lower incidence of miscarriage. Reported adverse effects include a high rate of intra-abdominal adhesion formation and a single case of iatrogenic premature menopause due to postoperative ovarian atrophy.

CONCLUSIONS

The available circumstantial evidence suggests that laparoscopic procedures designed to induce ovulation may be of value in the PCOS subject who, despite an exhaustive trial of clomiphene citrate therapy, remains anovulatory and is unable or unwilling to undergo gonadotropin therapy. However, because of the risks of postoperative ovarian adhesions, carefully constructed controlled trials must be performed before these procedures can be viewed as efficacious and safe.

Third annual William L. McGuire Memorial Lecture. "Studies on the estrogen receptor in breast cancer"--20 years as a target for the treatment and prevention of cancer

In 1973, McGuire and Chamness (In: O'Malley BW and Means AR (ed) Receptors for Reproductive Hormones, Plenum Press) summarized their work on the estrogen receptor in animal and human breast tumors, and in so doing described a target for therapeutic intervention. At that time there were no clinically useful antiestrogens, but the subsequent development of tamoxifen for breast cancer therapy has revolutionized the approach to treatment. Long-term adjuvant tamoxifen adjuvant therapy (i.e., greater than one year) has proven efficacy to enhance the survival of breast cancer patients. In addition, because there is an associated 40% decrease in contralateral breast cancer during adjuvant tamoxifen therapy and tamoxifen maintains bone density and reduces fatal myocardial infarction, clinical trials to test the worth of tamoxifen as a preventive for breast cancer in high risk women have started in the United States, United Kingdom, and Italy. Initial concerns that long-term tamoxifen causes endometrial cancer have been placed in perspective and analyzed by a review of the literature. Tamoxifen only doubles the normal risk of detecting endometrial cancer (i.e., to 2 per 1,000 tamoxifen-treated women per year), and 80% of these cases are early stage, good prognosis disease. Annual gynecological examinations and education are essential to provide reassurance for patients. The success of tamoxifen has encouraged the development of new antiestrogens to exploit the estrogen receptor as a therapeutic target. Droloxifene and TAT-59 mimic the metabolite 4-hydroxytamoxifen in having a high affinity for the estrogen receptor (Jordan et al, J Endocrinol 75:305, 1977). These drugs appear to have a pharmacological profile similar to tamoxifen. In contrast, the new pure antiestrogens have a distinct mechanism of action and will be valuable either as a first line therapy for advanced breast cancer or as a second line endocrine therapy after the failure of long-term adjuvant tamoxifen therapy. Finally, a new strategy is being developed to exploit the target site specific action of antiestrogens. Raloxifene, an antiestrogen with high affinity for the estrogen receptor but only weak estrogenicity for the uterus, prevents rat mammary tumorigenesis and maintains bone density. The drug is to be evaluated as a treatment for osteoporosis, but may also prevent the development of breast and endometrial cancer in a broad group of treated subjects. The identification of the estrogen receptor as a target for therapeutic opportunities has proved to be extremely beneficial for the control of breast cancer and has the added potential to control osteoporosis and coronary heart disease in women.

Effect of anordiol on ovarian hormone secretion, ovulation, and uterine and vaginal responses in the immature rat

The purpose of this investigation was to determine the estrogenic and antiestrogenic activities of the potential contraceptive agent anordiol in the immature rat. A dose of 2.45 mumol of anordiol (AD), estradiol (E2), clomiphene citrate (CC), tamoxifen (TA), or the vehicle alone was administered to rats on the 25th and 29th days of age. Serum hormones were measured between 16:00 and 17:00 on days 30, 31, and 32; organ weights were determined on day 32. Anordiol and estradiol treatments significantly increased ovarian and uterine weight and serum LH concentrations, but CC and TA had no effect on these parameters. Vaginal cornification occurred before day 32 in all rats receiving anordiol or estradiol and in 3/5 and 4/5 rats receiving CC and TA, respectively, but not in control rats. Based on serum progesterone levels, ovulation was induced only in rats receiving anordiol or estradiol. All of the compounds tested significantly increased serum testosterone above levels in control animals, but both AD and E2 induced ovulation without a further increase in serum testosterone. We conclude that in the immature rat anordiol produces estrogenic responses in the vagina, uterus and in the hypothalamic-pituitary-ovarian axis, whereas TA and CC are estrogenic only on the vaginal and uterine epithelium.

Effects of antiestrogens on adult and neonatal mouse reproductive organs

Estrogenic potencies of various antiestrogens, including keoxifene (Kx) and trifluoperazine (Tfp), on reproductive tracts of ovariectomized adult mice, and effects of neonatal Kx and Tfp on reproductive organs were studied in C57BL/Tw mice. In adult ovariectomized mice, weight, DNA, and protein of the uterus and vagina were increased by 3 daily injections of 100 micrograms clomiphene, tamoxifen (Tx), and nafoxidine, and of 1 microgram estradiol-17 beta (E), but not by Kx. Antiestrogenic potency of Kx was studied in adult mice given injections of E. Kx significantly suppressed the E-induced increase in weight, DNA, and protein in the uterus and vagina. Tfp (20 micrograms), known as a tranquilizer and an antiestrogen, had no estrogenic effect on either organ. Male and female mice given 5 daily injections of Kx or Tfp from the day of birth were examined at 30, 40, and 60 days of age. Weights of testis, epididymis, and seminal vesicle in neonatally Kx-treated mice were significantly lower than in controls at 30 and 40 days. Spermatozoa were not formed in the seminiferous tubules of Kx-treated mice, although spermatogenesis occurred at 60 days. In neonatally Kx-treated females, weight of the uterus at 60 days and of the vagina at 40 and 60 days was significantly lower than in controls. Corpora lutea were absent from the ovaries of Kx-treated females. In neonatally Tfp-treated mice of both sexes at all ages examined, no differences were found in organ weights or histology, other than lower spermatogenic indices at 40 and 60 days of age.(ABSTRACT TRUNCATED AT 250 WORDS)

A chemical classification of nonsteroidal antagonists of sex-steroid hormone action

A highly varied collection of nonsteroids have been reported over the last forty years as being able to exert an antihormonal action versus steroid hormones in vivo. This diversity is partly explained by the manifold molecular targets of these compounds which may be either enzymes or receptors (leading to inhibition of steroid production and action respectively) and by the different possible levels of interference within feedback loops between the central nervous system, pituitary, gonads and other peripheral organs. The present chapter is a chemist's classification of some of these structures often in the absence of detailed biochemical data. Nonsteroid antiestrogens (and estrogens) most often share a common feature with diethylstilbestrol and consequently the effects of structural modifications on biological activities can be studied in a rational manner. This is not the case for non-steroidal antiandrogens that we have only been able to classify into conventional chemical groups. Nor have any true lead compounds nor well-defined chemical classes been identified for nonsteroid antiprogestogens. This is however the only hormonal class where natural products play an important role.

Alterations in developing rat uterine cell populations after neonatal exposure to estrogens and antiestrogens

Exposure of rats to either estrogens or antiestrogens during early postnatal development reduces subsequent uterine growth as measured by uterine weight. However, individual uterine cell types respond differently to these agents and uterine weight alone cannot discern subtle or even large alterations in individual cell populations. Using a computerized planimetric technique, we estimated the prepubertal growth of the uterine luminal epithelium, endometrial stroma, glands, and circular and longitudinal muscle after exposure of neonatal rats (postnatal days 1-5) to the estrogens 17 beta-estradiol (E2), diethylstilbestrol (DES), or ethynylestradiol (EE), and the antiestrogens tamoxifen or clomiphene citrate. On postnatal day 26, the cross-sectional areas of the luminal epithelium, endometrial stroma, and circular muscle were reduced after estrogen exposure, compared to untreated controls, while longitudinal muscle cross-sectional area was not affected. Since cell densities (cell number/unit area) were increased, these estrogen-induced area reductions demonstrate a decrease in cell size. Total cell numbers, estimated as the product of cell type areas and their respective cell densities, were also reduced by neonatal estrogen exposure. The synthetic estrogens DES and EE were more potent than E2 with respect to reduction of uterine growth. Neonatal antiestrogen exposure caused large area reductions only in the uterine glands and luminal epithelium. Little change in cell density occurred in any cell population exposed to antiestrogen. These data demonstrate that the decreased uterine growth resulting from estrogen exposure during early postnatal development is a consequence of combined hypotrophy and hypoplasia in all cell types except longitudinal muscle while antiestrogen-induced morphological alterations were limited to hypoplasia having epithelial cell specificity.

The effect of fibrin sealant on mouse embryos

It is postulated that ovarian hyperstimulation prior to embryo transfer results in changes in the endometrium which lead to poor adhesive properties of the endometrium. Based on the properties of fibrin sealant which is used in human operative medicine, it is believed that adhesion of embryos to the endometrium during embryo transfer may be encouraged by the addition of fibrin sealant. The purpose of this study was to assess the effects of the addition of fibrin sealant to a mouse embryo/Ham's F-10 culture medium mixture. There was no statistical difference in the number of blastocysts developing from 138 embryos in standard medium compared with 139 cultured with the addition of fibrin sealant. It is concluded that fibrin sealant is not embryotoxic, and thus following further experimentation its eventual utilization in human in vitro fertilization/embryo transfer programs appears promising.

Metabolism of steroid-modifying anticancer agents

The application of steroid-modifying drugs as a strategy for the treatment of hormone-dependent cancers has gained increasing popularity during the past decade. However, it is important to point out and emphasize that very few of the agents were originally designed for their current application. Most were designed for other purposes, predominantly fertility control (e.g. LHRH agonists and the antiestrogens). Nevertheless, now it is possible to integrate their actions to design rational therapies. There are many reasons for the current interest in antisteroidal drugs. The initial euphoria over the potential ability of combination chemotherapy to cure breast and prostatic carcinoma has proved to be premature. Combination chemotherapy has many severe side-effects which limits patient acceptability, especially if the patient realizes that the likelihood of a cure is remote. In the main, antisteroidal therapies do not have many side-effects and those that do, e.g. aminoglutethimide, are the focus of increased efforts in drug design to produce increased drug specificity. Finally, there is a growing realization that hormone-dependent cancer control with a nontoxic, antisteroidal therapy may be the most acceptable approach currently available for early disease management. Chemotherapy would then be reserved as the final option for treatment. The description of drug metabolism has been central to the development of synthetic LHRH analogs and an understanding of the mode of action of nonsteroidal antiestrogens and antiandrogens. The discovery of steroid synthetic pathways has been essential for the development of the aromatase inhibitors. This whole area of endeavor has now become a major focus of attention for the medicinal chemist. A new generation of agents is entering clinical evaluation which will provide a wealth of valuable information about the successful (or unsuccessful?) methods to control hormone-dependent disease. Since the success or failure of a drug can often depend upon formulation, pharmacokinetics, bioavailability or metabolism, it is our hope that this overview might help solve some of the future problems.

Hormone excretion during early pregnancy following spontaneous and clomiphene citrate-induced ovulation

Endocrine changes during early pregnancy have been studied in 12 patients between days 35 and 91 from the last menstrual period. Ovulation had occurred spontaneously in five patients and was induced with clomiphene citrate (CC) in the remaining seven women. All the patients collected daily samples of early morning urine throughout the period of study; on each sample, human chorionic gonadotropin (hCG), pregnanediol-3-alpha-glucuronide (PGDG) and estrone-3-glucuronide (E1G) were measured by chemiluminescence immunoassay. No significant difference was observed between the two groups of patients with respect to the concentrations of hCG and PGDG. The excretion of E1G, however, was significantly higher in patients treated with CC. These data suggest that the induction of ovulation with CC may affect estrogen production in early pregnancy.

Antiestrogenic effect of clomiphene citrate in a multiple follicular stimulation protocol

End-organ antiestrogenic effects of clomiphene citrate (CC) have been demonstrated in the female reproductive tract at the levels of the ovary, cervix, and endometrium. However, it has not been established whether this effect is manifested during concomitant human menopausal gonadotropin (hMG) administration, as occurs in hMG/CC stimulations of multiple follicular development. To assess this question a review was made of serum estradiol (E2) and cervical mucus in 47 hMG and 56 hMG/CC stimulations on days -2, -1, 0, and +1 relative to the day of hCG administration. E2 levels (pg/ml) were significantly lower in the hMG as compared to the hMG/CC group. However, comparing the hMG and hMG/CC groups, cervical mucus scores were significantly higher in the former. Furthermore, an analysis of covariance demonstrated that the cervical mucus scores on each day were significantly lower in the hMG/CC group (P less than 0.001). Thus, in hMG/CC stimulations for in vitro fertilization (IVF), despite the concomitant administration of pharmacologic doses of hMG, CC exerts an antiestrogenic effect on at least one end organ, cervical mucus production. Potentially, this antiestrogenic effect in IVF stimulations would be exerted at other female reproductive tract sites including the endometrium; however, its clinical significance, if any, is unclear.

Oestrogenic and antioestrogenic actions in a series of triphenylbut-1-enes: modulation of prolactin synthesis in vitro

The oestrogenic and antioestrogenic activities of a series of substituted derivatives of 1,1,2 triphenylbut-1-ene have been determined using primary cultures of rat pituitary gland cells to monitor prolactin synthesis in vitro. The relative binding affinity of the agonists for the oestrogen receptor was consistent with their oestrogenic potency. Bis para substitution at C1 of 1,1,2 triphenylbut-1-ene with either phenolic or acetoxy groups produced partial agonists. The antioestrogenic properties were reversible by the incubation of cells with increasing concentrations of oestradiol. The results lend support to a hypothetical single binding site model of oestrogen action, based upon an adaptation of Belleau's macromolecular perturbation theory.

Inhibition of intestinal smooth muscle function by tamoxifen and clomiphene

The acute in vitro effects of the oestrogen antagonists clomiphene (a racemic mixture) and tamoxifen were examined upon spasmogen induced contractions of the guinea pig ileum. Both oestrogen antagonists inhibited the contractions produced by acetylcholine, the muscarinic agonist beta-methylcholine, histamine and bradykinin in a manner which suggests non competitive antagonism. Concentration effect curves to each of the spasmogens were unaffected using 0.1 mumoles/litre of either of the oestrogen antagonists. Clomiphene at 1 mumole/litre reduced the maximum response to the spasmogens by 20 to 50%. Tamoxifen at the same concentration also inhibited the contractions but to a much smaller extent. Clomiphene at the highest concentration tested 10 mumoles/litre completely suppressed contractions to all the spasmogens. Tamoxifen at 10 mumoles/litre completely suppressed contractions to beta-methylcholine and bradykinin. A residue of a response to acetylcholine and histamine remained and this was abolished by raising the concentration to 100 mumoles/litre. The data indicated that clomiphene was more potent than tamoxifen upon the inhibition of the contractions of the ileum. The results demonstrate a non specific effect of the oestrogen antagonists upon smooth muscle function and do not substantiate early reports of specific anticholinergic activity. The possibility of these effects contributing to both the side effects and the antitumor activity of the oestrogen antagonists is discussed.

Effect of clomiphene citrate on the rabbit ovary

The effect of clomiphene citrate on the rabbit ovary was studied in mature nulliparous rabbits pretreated with three consecutive doses ranging from 0.01-10.0 mg/kg per day. With increasing doses a trend of decrease in mean ovarian weight (mg/kg body weight) is observed 2 days after termination of treatment. Five days later a significant increase occurs, which then subsides again to control values on day 12 after termination of treatment. During this period, no matings or injections of luteinizing hormone were performed to trigger ovulation; consequently no ovulations are observed. Folliculogenesis appears as normally; number and morphology of follicles are within normal ranges. No endogenous, spontaneous gonadotropin surges are detected in blood serum up to the 7th day after termination of treatment (2 and 10 mg doses). The surface epithelium of the ovary resembles normal germinal epithelium; however, after treatment with high doses a "secretory"-like activity is observed, accompanied with ultrastructural changes.

The effect of clomiphene-citrate on broody turkey hens

The effect of clomiphene-citrate (CC) on broody turkey hens was examined in three experiments. Turkey hens were categorized as broody if found in the laying nest during 6 successive checks per day, if they were reluctant to leave the nest for a period of 24 hr or more, if they had ruffled feathers, and if their cloacal orifices were contracted so as to prevent vaginal exposure by abdominal massage during artificial insemination. In each experiment, 20 hens, selected as broody from commercial breeding flocks, were treated; half were treated with CC at a dosage of 6 mg/kg body weight/day (per os) for 5 consecutive days, and the rest (control) received parallel treatment with a placebo (CaCO3). In all experiments, the CC administration alleviated brooding behavior and increased egg production.

Dehydrogesterone treatment of endometrial luteal phase deficiency after ovulation induced by clomiphene citrate and human chorionic gonadotropin

Twenty infertile patients being treated with clomiphene citrate (CC) and human chorionic gonadotropin (hCG) for induction of ovulation, with a defective endometrial secretory pattern despite normal plasma levels of progesterone, estradiol, and prolactin, were entered into treatment plans on a random basis involving the following: CC-hCG plus dehydrogesterone (group 1), and CC-hCG (group 2). Success rates were similar in both groups (20% and 30%, respectively), based on a corrected endometrial defect during the second treated cycle. It is concluded that progestational agents are of low therapeutic value in endometrial luteal phase deficiency induced by CC.

Metabolism of clomiphene in the rat. Estrogen receptor affinity and antiestrogenic activity of clomiphene metabolites

Incubation of the nonsteroidal antiestrogen clomiphene with rat liver microsomes resulted in the formation of the 4-hydroxy-, N-desethyl-, and N-oxide metabolites, in qualitative contrast to results previously obtained analogously with rabbit microsomes, with which only the first two metabolites were detected. Metabolites were characterized by thin-layer chromatography in comparison with synthetic standards. They were similarly compared using low resolution electron ionization mass spectrometry, except for the N-oxide which was best characterized by fast atom bombardment mass spectrometry. Oral administration of clomiphene resulted in no detectable urinary elimination of the drug or its metabolites; 4-hydroxyclomiphene was the sole detectable elimination product in fecal extracts. The relative uterine cytosol estrogen receptor binding affinities, at 4 degrees, of 4-hydroxyclomiphene and the E-isomers of clomiphene, desethylclomiphene, and clomiphene N-oxide were, in turn, 331, 0.71, 0.62, and 0.88 (estradiol = 100). In the 3-day immature rat uterotropic assay, 4-hydroxyclomiphene had no significant uterotropic effect at doses up to 50 micrograms/day, but substantially inhibited that of estradiol (0.5 micrograms/day) at doses of 2 micrograms/day.

Induction of ovulation with combined human gonadotropins and dexamethasone in women with polycystic ovarian disease

A combined treatment of human menopausal gonadotropin (hMG), human chorionic gonadotropin (hCG), and dexamethasone was administered to 27 infertile patients with polycystic ovarian disease who failed to conceive with clomiphene citrate and hMG-hCG alone. Twenty-two (81%) of the patients ovulated according to basal body temperature and progesterone values, and 20 (74%) conceived during one to four treatment cycles. Fifteen (74%) pregnancies terminated in live full-term deliveries (14 singletons and 1 set of twins), and 5 (25%) have terminated in first-trimester abortions. Only one of the treatment cycles was complicated by moderate ovarian hyperstimulation. The average hMG dose required for the induction of ovulation was significantly reduced from 25 ampules with hMG-hCG alone to 18 ampules under the combined treatment (P less than 0.01). The combination of hMG-hCG and dexamethasone is an additional, safe, and effective nonsurgical treatment for women with polycystic ovarian disease who have failed to respond to an hMG-hCG regimen alone.

Menorrhagia associated with the wearing of IUD--the results of treatment with clomiphene citrate

The influence of clomiphene citrate was tested in 206 women suffering from menorrhagia following the insertion of an intrauterine device (IUD). Eighty-three percent felt relief during the therapy, 10% did not benefit and 7% complained of a worsening of their symptoms. Among the women who felt an improvement, 85% responded to the 250 mg/cycle dosage, and 15% required the 350 mg/cycle dosage. Women with shortened menstrual cycles required the higher dose treatment, i.e. 350 mg, compared with women with normal cycles (36% vs. 28%, respectively). The influence of placebo was 6%. The hypothesis is raised that the mechanism of action of clomiphene citrate is the correction of the hormonal disturbances in the luteal phase of the cycle following insertion of the IUD.

Hormonal and histological study of the luteal phase in women following aspiration of the preovulatory follicle

A hormonal and histologic study of 60 luteal phases was carried out in 40 patients during spontaneous and stimulated cycles before and after follicle puncture for oocyte recovery. The duration of the luteal phase was modified neither by follicle rupture nor by hormonal stimulation. The aspiration of a spontaneous preovulatory follicle caused a temporary deficiency in plasma progesterone (P) (P less than 0.01) on the third day following aspiration, and a higher prolactin (PRL) level (P less than 0.02) on the ninth day. Dystrophia of the endometrium was observed in one-third of the cases, whereas the P level was normal. In cycles stimulated by clomiphene citrate, no P deficiency was observed. When luteinizing hormone (LH) discharge occurred spontaneously, biopsies carried out 3 days following follicle aspiration indicated a normal secretory state of the endometrium, and the P level was higher from, the sixth day following aspiration (P less than 0.05), as compared with the control cycles. This phenomenon was not observed when human chorionic gonadotropin (hCG) was administered.

Antiestrogenic action of high-dose clomiphene in primates pituitary augmentation but with ovarian attenuation

Since the dominant follicle is selected by days 5 to 7 of the menstrual cycle, we assessed the differential effects of high-dose clomiphene (25 mg daily) by giving 5-day courses either before (days 1 to 5), during (days 5 to 9), or after (days 9 to 13) emergence of the selected dominant follicle in monkeys. Peripheral sera were obtained daily and assayed for follicle-stimulating hormone (FSH), luteinizing hormone (LH), 17 beta-estradiol (E2), and progesterone (P); serial laparoscopies were performed. Rather than enhancement of gonadotropin-dependent folliculogenesis during clomiphene treatment cycles, ovulation was delayed in 18 of 18 treatment cycles. Interestingly, the interval from treatment to next ovulation lengthened when clomiphene was given in the late follicular phase. Consistently, the clomiphene treatment cycles were characterized by a marked decline of the serum E2 during the 5 days of therapy, despite concurrent elevations of pituitary gonadotropins in circulation, especially FSH. These data suggest that a direct antiestrogenic effect of clomiphene imparted ovarian refractoriness to the prevailing, even enhanced, gonadotropin levels. The vulnerability of follicular maturation to these attenuating effects of clomiphene was greatest in the late follicular phase, well after the dominant follicle had been selected. Even after this clomiphene-induced ovarian hiatus and eventual resumption of new follicle growth, the initial apparent ovulation led to latent, severe corpus luteum insufficiency.

Induction of ovulation with menotropins in women with polycystic ovary syndrome

Twenty-four women with ovulatory infertility as a result of surgically or biochemically documented polycystic ovary syndrome (PCO) who had failed to conceive during clomiphene citrate therapy underwent a closely supervised menotropin treatment to induce ovulation. Evidence of ovulation was obtained in all patients treated, and major side effects were limited. Fourteen women conceived after an average of 2.4 treatment cycles; twin pregnancies occurred in 36% and spontaneous abortions occurred in 21%. Initial treatment cycles tended to be less successful than the subsequent treatment cycles. Serum 17 beta-estradiol (E2) levels were significantly augmented in the last 3 days before administration of chorionic gonadotropins (hCG) in treatment cycles resulting in conception compared to E2 levels in those cycles which resulted in ovulation only. A second hCG administration to trigger ovulation had to be given in 27% of the treatment cycles and seemed to be an indication of a less promising treatment cycle. Treatment cycles resulting in twin gestations did not differ from those resulting in singleton gestations; specifically, the E2 response was not increased. In summary, under a closely monitored regimen, menotropin therapy can be used in women with nonovulatory infertility as a result of PCO with considerable effectiveness and relative safety once clomiphene citrate treatment has failed.