Clomiphene citrate elicits estrogen agonistic/antagonistic effects differentially via estrogen receptors alpha and beta

Clomiphene citrate as a new modality in management of vaginal bleeding with depomedroxyprogesterone acetate (DMPA): A randomized controlled trial

BACKGROUND

Depo-medroxyprogesterone acetate (DMPA) functions as a contraceptive method by inhibiting the secretion of gonadotropins, which prevents follicular maturation and ovulation, as well as thinning of the endometrium leading to unscheduled vaginal bleeding and subsequent discontinuation of DMPA. Our study aimed to evaluate the efficacy and safety of clomiphene citrate (CC) in stopping bleeding among DMPA users.

MATERIALS AND METHODS

We randomly assigned 200 DMPA users using a computer-generated random numbers table in a 1:1 ratio to one of two groups; the study group, which received CC at a dose of 50 mg twice daily for five days (n = 100), and the control group, which received a placebo for five days (n = 100). Our primary outcome measure was the onset and duration of bleeding cessation. Secondary outcomes included endometrial thickness, recurrence of vaginal bleeding, and any reported side effects associated with CC use.

RESULTS

Clomiphene citrate significantly resulted in early cessation of vaginal bleeding in 83 % of the patients, which continued for three months of follow-up. In addition, the recurrence of vaginal bleeding was significantly reduced in the CC group compared to the control group (11 % vs. 67 %; p < 0.001). Endometrial thickness was significantly greater in the CC group than in the control group (p < 0.001). Breast tenderness was more frequently reported in the study group, with no difference in dyspareunia between the two groups.

CONCLUSIONS

Clomiphene citrate is effective in controlling bleeding among DMPA users. Further studies are encouraged to confirm our findings.

The Italian Wall Lizard Podarcis siculus as a Biological Model for Research in Male Reproductive Toxicology

Spermatogenesis is a genetically driven differentiation process that occurs in the testis and leads to the formation of spermatozoa. This process is extensively studied in several experimental models, particularly in vertebrates that share the morphological structure and functionality of the mammalian testis. Although reptiles are not generally considered biological models, the lizard Podarcis siculus has represented a suitable organism for the study of spermatogenesis over the years. In this lizard, the process of spermatogenesis is regulated by the interaction between systemic factors such as gonadotropins and local factors, i.e., molecules produced by the somatic and germinal cells of the testis. Many exogenous substances are able to alter the production of these regulative factors, thus altering the course of spermatogenesis, and P. siculus has proven to be an excellent model for studying the effects of various endogenous or exogenous substances on mechanisms underlying spermatogenesis. This review summarizes the available data on the effects of different substances on the control of spermatogenesis, highlighting the induced morphological and molecular alterations. Overall, the data show that sex hormone levels as well as the final stages of spermatogenesis are most affected by an imbalance of endogenous compounds or contamination by environmental pollutants. This is helpful for the male individual, since the damage, not affecting the spermatogonial stem cells, can be considered transient and not irreversible.

Kelulut Honey Regulates Sex Steroid Receptors in a Polycystic Ovary Syndrome Rat Model

Reproductive and metabolic anomalies in polycystic ovary syndrome (PCOS) have been associated with the dysregulation of sex steroid receptors. Kelulut honey (KH) has been shown to be beneficial in PCOS-induced rats by regulating folliculogenesis and the oestrus cycle. However, no study has been conducted to evaluate KH's effect on sex steroid receptors in PCOS. Therefore, the current study examined the effects of KH, metformin, or clomiphene alone and in combination on the mRNA expression and protein distribution of androgen receptor (AR), oestrogen receptor α (ERα), oestrogen receptor β (ERβ), and progesterone receptor (PR) in PCOS-induced rats. The study used female Sprague-Dawley rats, which were treated orally with 1 mg/kg/day of letrozole for 21 days to develop PCOS. PCOS-induced rats were then divided and treated orally for 35 days with KH, metformin, clomiphene, KH + metformin, KH+ clomiphene and distilled water. In this study, we observed aberrant AR, ERα, ERβ and PR expression in PCOS-induced rats compared with the normal control rats. The effects of KH treatment were comparable with clomiphene and metformin in normalizing the expression of AR, ERα, and ERβ mRNA. However, KH, clomiphene and metformin did not affect PR mRNA expression and protein distribution. Hence, this study confirms the aberrant expression of sex steroid receptors in PCOS and demonstrates that KH treatment could normalise the sex steroid receptors profile. The findings provide a basis for future clinical trials to utilize KH as a regulator of sex steroid receptors in patients with PCOS.

The edible plant Amaranthus hybridus (Amaranthaceae) prevents the biochemical, histopathological and fertility impairments in colibri®-treated female rats

Colibri® a commercial formulation of Imidacloprid severely impairs the reproductive function. This study aimed at evaluating the preventive effects of Amaranthus hybridus on the reproductive toxicity of colibri® in female rats. Eighty rats (n = 10/group) were orally treated with colibri® (22.5 mg/kg) and co-administered with either aqueous or methanolic extracts of A. hybridus (55 or 110 mg/kg) within four weeks. Control animals received either distilled water (10 ml/kg), clomiphene citrate or vitamin E. Starting from day 18 of treatment till the end, half of animals in each group (n = 5) was used for the fertility test whereas the remaining rats were kept under treatment until sacrifice. Blood, ovaries, uterus and vagina were collected after sacrifice for measurement of sexual hormones, oxidative stress markers and histological assessment. Exposure of female rats to colibri® was followed by a significant reduction (p < 0.05) in the ovarian and uterine weights, LH, FSH, estradiol and progesterone levels as well as ovarian superoxide dismutase, catalase and peroxidase activities. Moreover, alteration of ovaries, uteri and vagina histology, increase in MDA concentration, decrease in fertility and parturition indices and, pup's viability were recorded. Co-administration of colibri® and plant extracts significantly (p < 0.05-0.001) prevented the above-mentioned damages through biochemical parameter regulations. These results suggest that A. hybridus exerts a preventive effect against colibri®-induced female reproductive toxicity.

Comparison of the efficacy of letrozole stair-step protocol with clomiphene citrate stair-step protocol in the management of clomiphene citrate-resistant polycystic ovary syndrome patients

PURPOSE

We sought to compare the efficacy of the letrozole (LTZ) stair-step protocol with clomiphene citrate (CC) stair-step protocol in the management of 150 mg dose of CC-resistant polycystic ovary syndrome (PCOS) patients.

METHODS

We retrospectively compared a total of 61 patients diagnosed as being resistant to the traditional CC protocol who were subsequently managed using the LTZ stair-step protocol with CC-resistant 56 patients who were treated with CC stair-step protocol. The number of follicles ≥18 mm, endometrial thickness, time to ovulation, clinical pregnancy rates, multiple pregnancy rates, spontaneous abortion rates, live birth rates, and systemic side effects in patients were evaluated.

RESULTS

The mean time to ovulation was significantly shorter in the LTZ stair-step group than the CC stair-step group (17.3 ± 7.7 and 22.4 ± 8.1 days, respectively, p < 0.001). The ovulation rate was significantly higher in patients treated with LTZ stair-step protocol than those treated with the CC stair-step protocol (83.6% and 64.2%, respectively, p = 0.007). The clinical pregnancy rate was higher in the LTZ stair-step than the CC stair-step group (32.7% and 17.8%, respectively, p = 0.015). LTZ stair-step group had a significantly higher live birth rate than that of the CC stair-step group (27.8% and 14.2%, respectively, p = 0.012).

CONCLUSION

The LTZ stair-step protocol revealed higher ovulation, clinical pregnancy, and live birth rates with a shorter time to achieve ovulation than the CC stair-step protocol. Increment of the dose in the same cycle in both protocols did not cause any additional severe side effects.

Letrozole is superior to clomiphene citrate in ovulation induction in patients with polycystic ovary syndrome

Objective:

This study was aimed to compare the clinical outcomes of ovulation induction (OI) by timed intercourse with letrozole (LTZ) and clomiphene citrate (CC).

Methods:

Three hundred and twenty-three patients with polycystic ovary syndrome (PCOS) who underwent OI with LTZ or CC between February 2017 and November 2018 were included in this retrospective study. The patients were divided into two groups as the CC group (n=148) and the LTZ group (n=175). Endometrial thickness, follicular development, ovulation, clinical pregnancy, abortion, and live birth rates of the groups were analyzed.

Results:

The mean endometrium thickness of the CC group was 7.1±1.7 mm, and the LTZ group was 8.6±1.8 mm (p<0.001). The ovulation rate per cycle was higher in the LTZ group (93.1%) in comparison with the CC group (83.8%) (p=0.013). Clinical pregnancy rates were 52% in the LTZ group, and 41.2% in the CC group (p=0.047). LTZ with 44% of live birth rate was superior to CC with a 33% live birth rate (p=0.029).

Conclusions:

LTZ is an effective OI agent in PCOS patients. LTZ is superior to CC in terms of pregnancy rates and live birth rates. As a result, we recommend that LTZ should be the first-line treatment agent in patients with PCOS.

Effects of the Fertility Drugs Clomiphene Citrate and Letrozole on Kiss-1 Expression in Hypothalamic Kiss-1-Expressing Cell Models

Clomiphene citrate (CC) and letrozole stimulate the hypothalamic-pituitary-ovarian axis and are used widely as oral fertility drugs to induce folliculogenesis. We examined whether these drugs increase Kiss-1 expression in hypothalamic cell models. We utilized two hypothalamic cell models, mHypoA-50 and mHypoA-55, which originated from Kiss-1 neurons in the anteroventral periventricular (AVPV) nucleus and arcuate (ARC) nucleus of the mouse hypothalamus, respectively. The cells were stimulated with CC or letrozole, after which Kiss-1 mRNA expression was determined. CC stimulated Kiss-1 gene expression in mHypoA-50 and mHypoA-55 cells. The basal expression of Kiss-1 was significantly increased in the presence of estradiol (E2) in mHypoA-50 cells, and the CC-induced increase in Kiss-1 expression was not observed in the presence of E2 in these cells. In contrast, E2 did not modify the basal expression of Kiss-1 in mHypoA-55 cells, and CC-induced Kiss-1 expression was still observed in the presence of E2. The significant increase in Kiss-1 gene expression in mHypoA-50 and mHypoA-55 cells was blunted in the presence of estrogen receptor antagonists. Aromatase was expressed in mHypoA-50 and mHypoA-55 cells. Letrozole, an aromatase inhibitor, increased Kiss-1 expression in mHypoA-55 ARC cells but not in mHypoA-50 AVPV cells. Although the basal expression of Kiss-1 was increased by E2, letrozole did not modulate Kiss-1 expression in mHypoA-50 cells. Letrozole-induced Kiss-1 gene expression in mHypoA-55 cells was not modulated in the presence of E2. The fertility drugs CC and letrozole modulated Kiss-1 expression in hypothalamic cell models.

Enclomiphene citrate: A treatment that maintains fertility in men with secondary hypogonadism

Hypogonadism is an important issue among the male population. Treatments such as exogenous testosterone have become very popular. One of the adverse effects of testosterone is its suppression of fertility. This has lead to the use of alternative therapies such as selective estrogen receptor modulators (SERMs) that aim to correct hypogonadism without reducing fertility. Areas covered: The SERM, clomiphene citrate, which is approved by the FDA for the treatment of ovarian dysfunction, has been shown to have beneficial effects on male hypogonadism. Clomiphene citrate exists as a mixture of both the cis-isomer (zuclomiphene) and the trans-isomer (enclomiphene). The literature has suggested that most of the beneficial effects of clomiphene are due to the trans-isomer enclomiphene. Zuclomiphene contributes little to the intended outcomes. The purpose of this drug profile is to examine the available literature on the trans-isomer enclomiphene. Expert opinion: Enclomiphene has been shown to increase testosterone levels while stimulating FSH and LH production. Initial studies demonstrated that enclomiphene maintains the androgenic benefit of clomiphene citrate without the undesirable effects attributable to zuclomiphene. This article reviews the difficulties associated with the FDA approval of a new molecular entity related to the treatment of hypogonadism.

Exploring the Role of Estrogens in Lizard Spermatogenesis through the Study of Clomiphene and FSH Effects

Spermatogenesis is a fascinating biological process aiming to generate haploid spermatozoa from diploid spermatogonia through a specific hormonal network between gonadotropins and steroids. Increasing evidence suggests that the primary female sex hormone estrogen plays an active role in this process. This research points out on the role of estrogen during lizard spermatogenesis by using three experimental approaches: (1) exposure to an analogue of nonsteroidal estrogen as Clomiphene citrate that acts both as estrogen agonist and antagonist; (2) exposure to the gonadotropin FSH; and (3) exposures to FSH followed by Clomiphene. Histological and immunohistochemical results demonstrate that in the lizard Podarcis sicula during the mating period, Clomiphene as well as FSH determines the breakdown of spermatogenesis and the epididymal regression, presumably through estrogens input as indirectly demonstrated by the appearance of ERα and vitellogenin in the liver. The ability of Clomiphene to restore the gonadal natural condition after FSH treatment is also demonstrated. Finally, data indicate that lizard testis and epididymis control their morphophysiology regulating the intracellular presence of ERα.

Alternative treatment modalities for the hypogonadal patient

Testosterone (T) deficiency syndrome (TDS) is a prevalent condition, commonly managed with exogenous T. Despite an abundance of T formulations, alternative treatments are often sought for various reasons. To evaluate outcomes of alternative therapies, a PubMed search was performed of all publications that included men with TDS from 1990 through October 2013, with results summarized. Proposed mechanisms of action were also reviewed to provide a pathophysiologic basis for reported outcomes. Nonpharmacologic therapies that increase endogenous T are weight loss, exercise, and varicocelectomy, while medications used off-label include aromatase inhibitors, human chorionic gonadotropin, and selective estrogen receptor modulators. All reported therapies increase T, while changes in estradiol and adverse events vary by therapeutic class. Although limited data preclude direct comparisons between therapies, exercise and weight loss alone or in combination with medications may be considered first line. The role for surgical therapy in TDS remains undefined and requires further study.

Effect of estradiol and clomiphene citrate on Erk activation in breast cancer cells

The mitogen-activated protein kinase (MAPK) signaling pathway plays key roles in the transmission of proliferative signals in normal and dysregulated cells. Nevertheless, some studies have shown that activation of the extracellular regulated kinases 1/2 (Erk1/2) is involved in apoptosis. In this study, we evaluate the effect of two fertilizing drugs, clomiphene citrate and estradiol, on the activation of Erk1/2 and the viability of two breast cancer cell lines, MCF-7 (hormone dependent) and BT20 (hormone independent).We show that both drugs induce Erk1/2 phosphorylation in MCF-7 and BT20 cells despite their opposite effect on cell viability. In fact, clomiphene citrate is significantly proapoptotic while estradiol promotes cell proliferation. The fact that phospho-Erk1/2 is a common element to both mechanisms suggests that specific factors deciding between proliferation and apoptosis must be operative downstream of this signaling pathway.

Nuclear receptors and their selective pharmacologic modulators

Nuclear receptors are ligand-activated transcription factors and include the receptors for steroid hormones, lipophilic vitamins, sterols, and bile acids. These receptors serve as targets for development of myriad drugs that target a range of disorders. Classically defined ligands that bind to the ligand-binding domain of nuclear receptors, whether they are endogenous or synthetic, either activate receptor activity (agonists) or block activation (antagonists) and due to the ability to alter activity of the receptors are often termed receptor "modulators." The complex pharmacology of nuclear receptors has provided a class of ligands distinct from these simple modulators where ligands display agonist/partial agonist/antagonist function in a tissue or gene selective manner. This class of ligands is defined as selective modulators. Here, we review the development and pharmacology of a range of selective nuclear receptor modulators.

Clomiphene citrate potentiates the adverse effects of estrogen on rat testis and down-regulates the expression of steroidogenic enzyme genes

OBJECTIVE

To investigate the antiestrogenic effect of clomiphene citrate (CC) in male rats estrogenized with estradiol-3-benzoate (EB).

DESIGN

Prospective experimental study.

SETTING

Laboratory.

ANIMALS

Adult male albino rats (Holtzman strain).

INTERVENTION(S)

CC was given alone or in combination with EB.

MAIN OUTCOME MEASURE(S)

Testicular function and steroidogenic enzyme gene expression were evaluated in control versus treated groups.

RESULT(S)

EB after 30 days of treatment induced a rise in TUNEL-positive germ cells adversely affecting spermatogenesis with complete absence of elongated spermatids or sperms. CC alone had only a moderate effect. In contrast, CC+EB synergistically inflicted more adverse effects as apoptotic germ cells per tubule rose further. Significant down-regulation in expression of testicular steroidogenic enzyme genes StAR, p450scc, 3β-HSD, and p450c17 was observed. In the EB-alone group, aromatase gene expression in the testis was up-regulated but reversed in brain and liver tissues. CC alone had little modulatory effect on aromatase expression. On the other hand, CC+EB countered the EB-induced rise of aromatase expression in the testis.

CONCLUSION(S)

The above findings indicate that CC in the presence of estrogen synergistically potentiates more adverse effects in testis, inhibiting expression of upstream steroidogenic enzyme genes and leading to disruption of steroidogenesis.

Effect of infertility treatment and pregnancy-related hormones on breast cell proliferation in vitro

BACKGROUND

Breast cancer development involves a series of mutations in a heterogeneous group of proto-oncogenes/tumor suppressor genes that alter mammary cells to create a microenvironment permissive to tumorigenesis. Exposure to hormones during infertility treatment may have a mutagenic effect on normal mammary epithelial cells, high-risk breast lesions and early-stage breast cancers. Our goal was to understand the association between infertility treatment and normal and cancerous breast cell proliferation.

METHODS

MCF-10A normal mammary cells and the breast cancer cell lines MCF-7 [estrogen receptor (ER)-positive, well differentiated] and HCC 1937 (ER-negative, aggressive, BRCA1 mutation) were treated with the weak ER activator clomiphene citrate and hormones that are increased during infertility treatment. Direct effects of treatment on cell proliferation and colony growth were determined.

RESULTS

While clomiphene citrate had no effect on MCF-10A cells or MCF-7 breast cancer cells, it decreased proliferation of HCC 1937 versus untreated cells (P= 0.003). Estrogen had no effect on either MCF-10A or HCC 1937 cells but, as expected, increased cell proliferation (20-100 nM; P≤0.002) and colony growth (10-30 nM; P< 0.0001) of MCF-7 cells versus control. Conversely, progesterone decreased both proliferation (P= 0.001) and colony growth (P= 0.01) of MCF-10A cells, inhibited colony size of MCF-7 cells (P= 0.01) and decreased proliferation of HCC 1937 cells (P= 0.008) versus control. hCG (100 mIU/ml) decreased both proliferation (P ≤ 0.01) and colony growth (P ≤ 0.002) of all three cell lines.

CONCLUSIONS

Although these data are preclinical, they support possible indirect estrogenic effects of infertility regimens on ER-positive breast cancer cells and validate the potential protective effect of pregnancy-related exposure to hCG.