Is alpha2-macroglobulin important in female stress urinary incontinence?

BACKGROUND: Loss of mechanical stability of the urethra and bladder is thought to be important in the development of stress urinary incontinence (SUI). The vaginal wall is the main supporting tissue for pelvic organs and changes in components of supporting tissues are known to be involved in the pathophysiology of SUI. METHODS: We evaluated changes in expression of alpha2-macroglobulin (alpha2-M), a protease inhibitor, in vaginal wall tissues from premenopausal women (aged 42-45 years) with SUI (n = 28) compared with menstrual cycle-matched continent women (controls, n = 29). The distribution of alpha2-M in vaginal wall tissues and fibroblasts was analysed by immunohistochemistry and immunofluorescence. Expression levels of alpha2-M mRNA and protein was determined by relative real-time quantitative PCR and enzyme-linked immunosorbent assay, respectively. Protease inhibition was measured to assess bioactivity. RESULTS: Vaginal wall tissues do express alpha2-M. Expression of alpha2-M mRNA and protein was significantly higher in tissues from controls compared to women with SUI in both proliferative and secretory phases (P < 0.05). Protease inhibitory activity of alpha2-M was significantly higher in tissues from controls compared to women with SUI in the secretory phase (P < 0.05), but we found no difference in the proliferative phase between groups. alpha2-M protein level was lower in the proliferative phase than the secretory phase in both controls and SUI patients, while for alpha2-M mRNA this was found only in controls. CONCLUSIONS: Decreased expression of alpha2-M mRNA and protein and protease inhibitory activity in the vaginal wall tissues of women with SUI may contribute to the development of SUI.

Differences in mRNA and protein expression of small proteoglycans in vaginal wall tissue from women with and without stress urinary incontinence.

BACKGROUND: To investigate changes in mRNA and protein levels of biglycan (BGN), decorin (DCN) and fibromodulin (FMOD) in vaginal wall tissue from women with stress urinary incontinence (SUI) compared to menstrual-cycle matched continent women. METHODS: We determined mRNA expressions of BGN, DCN and FMOD by quantitative real-time PCR. They were localized in vaginal wall tissue by immunohistochemistry. We performed western blot analysis to examine protein expression. RESULTS: BGN, DCN and FMOD co-localized with collagen and elastin in the extracellular matrix (ECM) of vaginal wall tissue from both groups. The mRNA expression of FMOD was significantly lower in cases versus controls in the proliferative phase (P = 0.03). DCN mRNA expression in cases was higher in the proliferative (P = 0.05) and secretory phases (P = 0.02) versus controls. BGN mRNA expression showed no significant differences in either phase. Protein expression of FMOD in cases was lower in the proliferative phase versus controls (six out of nine pairs), whereas DCN and BGN protein expression in the secretory phase in cases was higher (seven out of nine pairs). CONCLUSION: BGN, DCN and FMOD expressions in vaginal wall tissue differ in women with SUI and are hormonally modulated. Differences in small proteoglycans may contribute to the altered pelvic floor connective tissues found in these women.

Double-blind, placebo-controlled study of Fertilityblend: a nutritional supplement for improving fertility in women.

PURPOSE: To determine the impact of nutritional supplementation on female fertility. METHODS: A double blind, placebo-controlled study of the effects of FertilityBlend for Women, a proprietary nutritional supplement containing chasteberry, green tea, L-arginine, vitamins (including folate) and minerals, on progesterone level, basal body temperature, menstrual cycle length, pregnancy rate and side-effects. RESULTS: Ninety-three (93) women, aged 24-42 years, who had tried unsuccessfully to conceive for six to 36 months, completed the study. After three months, the FertilityBlend (FB) group (N = 53) demonstrated a trend toward increased mean mid-luteal progesterone (P(ml)), but among women with basal pretreatment P(ml) < 9 ng/ml, the increase in progesterone was highly significant. The average number of days with luteal-phase basal temperatures over 98 degrees F increased significantly in the FB group. Both short and long cycles (< 27 days or > 32 days pretreatment) were normalized in the FB group. The placebo group (N = 40) did not show any significant changes in these parameters. After three months, 14 of the 53 women in the FB group were pregnant (26%) compared to four of the 40 women in the placebo group (10%; p = 0.01). Three additional women conceived after six months on FB (32%). No significant side-effects were noted. CONCLUSION: Nutritional supplements could provide an alternative or adjunct to conventional fertility therapies.

Collagen metabolism and turnover in women with stress urinary incontinence and pelvic prolapse.

The aim of this study was to investigate quantitative mRNA expression of matrix metalloproteinases MMP-1, MMP-2, MMP-9, and their inhibitors, the tissue inhibitors of metalloproteinases TIMP-1, TIMP-2 and TIMP-3, in vaginal wall tissue from women with stress urinary incontinence compared to continent controls. Vaginal wall tissues were obtained from 7 women with stress urinary incontinence/severe pelvic prolapse and 15 continent controls. RNA was then extracted and quantified. Quantitative competitive reverse transcription (QC-RT-PCR) was carried out with oligonucleotide primers to quantify MMP-1, MMP-2, MMP-9, TIMP-1, TIMP-2 and TIMP-3 mRNA expression. Stress continent women demonstrated a significant decrease in TIMP-1 and mRNA expression (P = 0.03). There was no difference in TIMP-2, TIMP-3, MMP-2 or MMP-9 mRNA expression between stress incontinent women and controls. However, MMP-1 mRNA expression was significantly increased (P = 0.05) in the incontinent group and the MMP-1/TIMP-1 ratio (P = 0.04) was consistent with increased collagen degradation in the stress incontinence. Stress incontinent women demonstrated an increase in MMP-1 mRNA expression and a decrease in the inhibitor TIMP-1 mRNA expression. Both these findings are consistent with increased collagen breakdown as a pathologic etiology of incontinence.

A double-blind placebo-controlled study of ArginMax, a nutritional supplement for enhancement of female sexual function.

This study was open to women over the age of 21 years with an interest in improving their sexual function. Of the 77 participants, 34 received ArginMax and 43 received a placebo. ArginMax for Women is a proprietary nutritional supplement consisting of extracts of ginseng, ginkgo, and damiana, L-arginine, multivitamins, and minerals. After 4 weeks, 73.5% of the ArginMax group improved in satisfaction with their overall sex life, compared with 37.2% of the placebo group (p < 0.01). Notable improvements were also observed in sexual desire, reduction of vaginal dryness, frequency of sexual intercourse and orgasm, and clitoral sensation. No significant side effects were noted.

Gonadotropin-releasing hormone messenger ribonucleic acid and protein expression in Vero cells.

PURPOSE: Interleukin-1 (IL-1) is a major regulator of local cellular interactions during embryonic implantation. We hypothesized that gonadotropin-releasing hormone (GnRH) may also play a role in the embryonic/epithelial dialogue during early implantation. To examine this hypothesis, we examined the ability of IL-1 to regulate GnRH mRNA and protein expression in Vero cells. METHODS: Viable Vero cells (1 x 10(5)/well) were cultured in multiple-well tissue culture plates for in vitro studies and in 4-well chamber slides for immunohistochemical study. Confluent Vero cells were cultured with increasing concentrations of recombinant human IL-1 beta for an additional 24 hr. Vero cell expression of GnRH and GnRH receptor mRNAs was measured with polymerase chain reaction (PCR) and nested PCR, respectively. GnRH protein expression was validated by immunohistochemistry study. The quantitative level of GnRH mRNA expression regulated by IL-1 beta in Vero cells was determined by quantitative competitive PCR (QC PCR) with standard curve methodology. RESULTS: RT-PCR revealed beta-actin, GnRH, and GnRH receptor mRNA expression in Vero cell cultures. Immunostaining confirmed the presence of GnRH protein in Vero cells. Quantitative PCR demonstrated IL-1 beta up-regulation of Vero cell GnRH mRNA expression (p < 0.05). CONCLUSIONS: These results suggest that Vero cell mRNA and protein expression of GnRH may play a substantial role in early embryo/epithelial dialogue during embryo coculture, with an embryotrophic effect due to expression of GnRH by Vero cells.

Interleukin-1beta regulates urokinase plasminogen activator (u-PA), u-PA receptor, soluble u-PA receptor, and plasminogen activator inhibitor-1 messenger ribonucleic acid expression in cultured human endometrial stromal cells.

The interleukin-1 (IL-1) system plays an integral role in local intercellular interactions during implantation. In addition, the plasminogen activator system, especially urokinase plasminogen activator (u-PA), plasminogen activator inhibitor (PAI-1), and u-PA receptor (u-PAR), are crucial during embryo implantation. Decidualization and implantation are complex processes dependent upon several proteases, including u-PA, and IL-1 is known to affect PA activity in several cell types. We investigated the role of IL-1beta in regulating u-PA, PAI-1, u-PAR, and soluble u-PAR messenger ribonucleic acid (mRNA) expression in cultured human endometrial stromal cells using quantitative competitive PCR. For confirmation of the mRNA data, we measured PAI-1 and u-PAR protein by enzyme-linked immunosorbent assay. Confluent stromal cell cultures treated with progesterone and estradiol for 9 days were stimulated with IL-1beta, and IL-1beta plus IL-1beta antibody for an additional 24 h. Total RNA was extracted, reverse transcribed, and coamplified using quantitative and competitive PCR with internal standards. IL-1beta increased PAI-1, u-PAR, and soluble u-PAR expression in a dose-dependent manner, and this result was reversed by anti-IL-1beta antibody treatment. u-PA mRNA expression was not dependent on IL-1beta. These results suggest that IL-1 may be important in regulating PAI-1 and u-PAR during stromal cell decidualization before implantation.

Interleukin (IL)-1beta regulation of IL-1beta and IL-1 receptor antagonist expression in cultured human endometrial stromal cells.

The interleukin (IL)-1 system is a major regulator of local cellular interactions during embryonic implantation. Because IL-1beta and IL receptor antagonist (IL-1ra) are both expressed in human endometrium, we hypothesized that an appropriate ratio of IL-1beta to IL-1ra might favor the process of embryo implantation. Therefore, we investigated IL-1 regulation of the quantitative ratio of IL-1beta/IL-1ra messenger RNA (mRNA) expression in human endometrial stromal cells using quantitative competitive PCR, as well as intracellular protein expression after stromal cell solubilization. Confluent stromal cell cultures were stimulated with human IL-1beta (0-1000 IU/mL) for 24 h. After 24 h, total RNA was extracted, reverse transcribed, and coamplified by PCR with a defined amount of internal standard. The quantitative ratio was determined by the density of target to the internal standard. After culture with IL-1beta for 24 and 48 h, stromal cells were solubilized, and the intracellular protein levels of IL-1beta and IL-1ra were measured by enzyme-linked immunosorbent assay. The IL-1beta and IL-1ra mRNA were both up-regulated, and IL-1R tI mRNA was down-regulated, by IL-1beta in a dose-dependent manner. The quantitative ratio of IL-1beta to IL-1ra mRNA was constant with the presence of increasing concentrations of IL-1beta (1-1000 IU/mL). IL-1beta and IL-1ra protein was not detected in conditioned media of cultures before addition of IL-1beta. IL-1beta and IL-1ra protein levels increased with increasing amounts of IL-1beta after solubilization of stromal cells. The IL-1beta was detectable after 12 h of culture, in comparison with IL-1ra, which was detectable after 24 h of IL-1beta stimulation. These results suggest that IL-1 may play a crucial role in embryo-maternal interaction by regulating stromal cell expression of IL-1beta and IL-1ra, resulting in an appropriate ratio during the process of embryonic implantation.

Expression of vascular endothelial growth factor mRNA in human preimplantation embryos derived from tripronuclear zygotes.

OBJECTIVE: To detect the expression of vascular endothelial growth factor (VEGF) mRNA and/or secretion of VEGF protein by human preimplantation embryos. DESIGN: Human preimplantation embryos not suitable for uterine transfer were examined for beta-actin and VEGF mRNA expression. Culture media from normally fertilized and developing preimplantation embryos were assessed for VEGF protein secretion. SETTING: Clinics and academic research laboratories at the Departments of Obstetrics and Gynecology at the Stanford University, Palo Alto, California and the Heinrich-Heine-University, Düsseldorf, Germany. PATIENT(S): Couples undergoing IVF by intracytoplasmic sperm injection for various reasons. INTERVENTION(S): Six unfertilized oocytes and 33 pathologically fertilized (tripronucleic, 3PN) preimplantation embryos were examined for VEGF mRNA expression, and 16 embryos were examined for VEGF protein secretion. MAIN OUTCOME MEASURE(S): Embryonic expression of VEGF mRNA and VEGF protein as determined by reverse transcription (RT)/nested polymerase chain reaction (PCR) and ELISA. RESULT(S): VEGF mRNA and protein could not be detected in unfertilized oocytes. However, 30/33 preimplantation embryos did express VEGF mRNA (11/12 10-to-16-cell embryos, 3/4 morulae, 11/12 early blastocysts, 5/5 hatched blastocysts). The VEGF protein level was below the sensitivity of the ELISA. CONCLUSION(S): Production of VEGF may give the embryo the ability to induce neoangiogenesis at the implantation site, thus creating an environment necessary for its survival.

Is there a place for biochemical embryonic preimplantational screening?

The advent of assisted reproductive techniques such as intracytoplasmic sperm injection has markedly reduced the problem of unsuccessful fertilization in modern IVF. However, pregnancy rates and 'take-home-baby' rates remain unsatisfactorily low. Attempts to overcome low pregnancy rates by transferring a larger number of embryos to the mother often result in multiple pregnancies. The preimplantation embryo synthesizes several proteins that may signal its presence to the maternal system, and the interaction between the embryo and the endometrium is controlled, at least in part, by cytokines and growth factors. However, little is known about the interactions between the embryonic and maternal proteins. A better understanding of normal preimplantation embryo development may lead to improved in vitro culture conditions and higher pregnancy rates. This review gives an overview of the current knowledge of the embryonic factors produced during the preimplantation period. The development of the interleukin 1 system for screening human preimplantation embryos is also discussed. Current biochemical embryonic screening procedures are highly experimental, but increasing knowledge of the physiology of embryonic development might enable these screening procedures to be used to identify embryos that are capable of successful implantation.

Human oviductal gonadotropin-releasing hormone: possible implications in fertilization, early embryonic development, and implantation.

The oviduct is host to gametes and early embryos at a critical point in their lives. It is clear that the interactions of gametes/early embryo with the maternal oviduct in an autocrine and paracrine manner provide a microenvironment that enhances fertilization, early embryonic development, and implantation. Moreover, there is considerable evidence that an extrahypothalamic GnRH may play a substantial role as a molecular autocrine/paracrine regulator in these events. Gametes and preimplantation embryos express GnRH and GnRH receptor at both messenger ribonucleic acid (mRNA) and protein levels. However, whether GnRH is produced by the human oviduct has not yet been demonstrated. We used RT-PCR and immunohistochemical techniques to investigate GnRH mRNA and protein expression in human fallopian tubes throughout the menstrual cycle of premenopausal fertile patients. Our results, at both the mRNA and protein levels, revealed cycle-dependent production of an oviductal GnRH with expression during the luteal phase. Moreover, GnRH immunostaining was localized in the tubal epithelium during the luteal phase. On the basis of these data, we suggest that during reproductive life, oviductal GnRH may play a substantial paracrine/autocrine role in human fertilization, early embryonic development, and implantation.

The role of gonadotropin-releasing hormone in murine preimplantation embryonic development.

Previous studies have established the presence of an extrahypothalamic GnRH in a variety of tissues. GnRH receptor is known to be present in the placenta, which produces and secretes the decapeptide from the very early stages of placentation. We hypothesized that GnRH may play a role in the preimplantation development of embryos. To examine this hypothesis, we assessed GnRH and GnRH receptor messenger RNA (mRNA; RT-PCR) and protein expression (Immunohistochemistry) in preimplantation murine embryos at various developmental stages. Furthermore, preimplantation murine embryos were cultured with GnRH agonist and antagonist in vitro to assess the influence of GnRH analogs on embryo development. GnRH is expressed in the developing mouse embryo from morula to hatching blastocyst stages at the mRNA and protein levels. GnRH receptor mRNA is also present in the developing embryos studied. Preimplantation embryonic development was significantly enhanced by incubation with increasing concentrations of GnRH agonist and is significantly decreased by GnRH antagonist compared with that in the control group. Moreover, GnRH antagonist (5 and 10 microM) was able to completely block embryo development. The deleterious effect of GnRH antagonist on embryo development was reversed by increasing concentrations of the agonist, as determined by the number of embryos reaching the blastocyst stage.

Expression of mRNA for vascular endothelial growth factor transmembraneous receptors Flt1 and KDR, and the soluble receptor sflt in cycling human endometrium.

The aim of this study was to quantify and localize the mRNA expression of the vascular endothelial growth factor (VEGF) receptors Flt1, KDR and sflt, in human endometrium throughout the menstrual cycle. Since neoangiogenesis is crucial during embryonic implantation, we postulate that endometrial receptivity to VEGF may be altered during the luteal phase in order to support implantation. Human endometrium was collected and specified as early proliferative (n = 3), mid-proliferative (n = 4), late proliferative (n = 3), early secretory (n = 2), mid-secretory (n = 4), and late secretory (n = 4). Competitive reverse transcription-polymerase chain reaction (RT-PCR) was performed to evaluate the mRNA values throughout the menstrual cycle. Additionally, four samples were separated into epithelial and stromal-enriched cell fractions and competitive RT-PCR was carried out to specify the distribution of the mRNA expression. While mRNA for the transmembraneous receptors Flt1 and KDR was shown to be present at almost constant values throughout the menstrual cycle, the soluble receptor, sflt, had a three-fold higher level of transcription during mid-proliferative and late proliferative when compared with early proliferative and the entire secretory phase. The expression of Flt1, KDR and sflt mRNA was detected in both isolated endometrial epithelial and stromal cell fractions. In conclusion, the down-regulation of sflt, which functions as a soluble antagonist, during the luteal phase may act to sensitize the maternal endothelial receptors to angiogenetic stimuli secreted by the implanting embryo.

GnRH mRNA and protein expression in human preimplantation embryos.

Gonadotrophin-releasing hormone (GnRH) regulates gonadotrophin biosynthesis and release in the anterior pituitary via specific receptors. Extrapituitary expression and action of GnRH have been demonstrated in several species. A possible role for GnRH in preimplantation embryonic development, endometrial preparation, and the implantation process has been previously suggested. Moreover, the presence of an immunoreactive GnRH in preimplantation embryos has been demonstrated in different species; however, there are no data for human embryos. We postulate that in humans GnRH may play a role in preimplantation embryonic development as well as in the implantation process. To examine this hypothesis, we assessed GnRH and GnRH-receptor mRNA and protein expression in human preimplantation embryos with three pronuclei. GnRH is expressed in peri-implantation human embryos at both the mRNA and protein level. GnRH-receptor mRNA is also present in the embryos studied. Immunohistochemical localization of GnRH showed intense staining in all the blastomeres at morula stage as well as in the trophectoderm and inner cell mass of the blastocysts. The results of the present study challenge the widely held view that GnRH has a predominantly central action, and suggests a pathway to describe a local role for the GnRH system in successful preimplantation embryonic development and implantation.

Restructuring residency training in obstetrics and gynecology.

This essay presents a brief review of the history advocating a restructuring of residency training to increase the flexibility of the experience. The advantages for both the general obstetrician-gynecologist and the subspecialist are reviewed.

Independent regulation of matrix metalloproteinase-9, tissue inhibitor of metalloproteinase-1 (TIMP-1), and TIMP-3 in human endometrial stromal cells by gonadotropin-releasing hormone: implications in early human implantation.

Early human trophoblast shows dramatic invasive properties during early pregnancy. The simultaneous synthesis of matrix metalloproteinases (MMPs) and their specific tissue inhibitors (TIMPs) in both human trophoblast and decidual membranes suggests that their controlled and balanced expression is crucial for the rapid matrix remodeling and controlled invasion during early pregnancy. Recently, we have described the presence of an extrahypothalamic GnRH immunologically, biologically and chemically identical to the hypothalamic hormone in periimplantation human embryos. Moreover, the production of this decapeptide by the human trophoblast during the early stages of placentation is well documented. TIMP-1 and -3 messenger ribonucleic acid (mRNA) expression in cultured stromal cells and protein secretion into the medium were significantly decreased by GnRH agonist compared to that in control groups. Moreover, expression of TIMP-1 was affected to a greater extent than that of TIMP-3. GnRH antagonist ablated the down-regulation of TIMPs by the GnRH agonist. MMP-9 mRNA expression was not detected in the control groups or in the groups treated with GnRH analogs. Our results provide evidence that trophoblastic GnRH may play an important role in placental tissue organization and in the early embryo-maternal dialogue by enhancing trophoblast invasion through the specific inhibition of TIMPs.

Interleukin-1 receptor antagonist prevents embryonic implantation by a direct effect on the endometrial epithelium.

OBJECTIVE: To investigate the embryonic and/or endometrial molecular mechanisms underlying the antiimplantation effect of interleukin-1 receptor antagonist (IL-1ra). DESIGN: Controlled experiment. SETTING: Animal facilities at Stanford University and laboratories of the Instituto Valenciano de Infertilidad and the University of Sydney. ANIMAL(S): Twelve-week-old B6C3F-1 female mice. INTERVENTION(S): Intraperitoneal injections of recombinant human IL-1ra during the periimplantation period. MAIN OUTCOME MEASURE(S): Implantation sites, embryonic morphology, and viability. Polymerase chain reaction and immunohistochemistry for integrins and extracellular matrices and transmission electron microscopy of endometrium in IL-1ra-treated versus control animals. RESULT(S): Pregnancy rates in control and IL-1ra-injected animals were 60% and 13%, respectively. At day 8 of pregnancy, flushing of uteri obtained from the treated group resulted in 32 blastocysts. Six pseudopregnant animals received IL-1ra-treated blastocysts (left horn) and control blastocysts (right horn), resulting in one pregnancy, with two embryos and one embryo in the left and right horns, respectively. At day 4 of pregnancy, IL- 1ra down-regulated alpha4 mRNA with use of the polymerase chain reaction. Immunohistochemistry showed a decrease of alpha4, alpha v, and beta3, and transmission electron microscopy revealed inhibition of transformation of the plasma membrane. CONCLUSION(S): Impairment of embryonic adhesion with IL-1ra is mediated through a direct effect on transformation of the epithelial plasma membrane at the time of implantation as a result of down-regulation of alpha4, alpha v, and beta3.

Expression of interleukin-1 system mRNA in single blastomeres from human preimplantation embryos.

Gathering knowledge about the molecular events during preimplantation development is one of the most important challenges in in-vitro fertilization (IVF). The interleukin-1 (IL-1) system has been shown to be intimately involved in embryonic implantation. The aim of our study was to detect the major components of the IL-1 system in single blastomeres from human preimplantation embryos and to relate our findings to the further development of the biopsied embryos in vitro. Single blastomeres were removed from morphologically normal embryos obtained from dipronuclear zygotes and examined by reverse transcription (RT)-nested polymerase chain reaction (PCR). Expression of beta-actin (external standard), IL-1beta, IL-1 receptor antagonist (IL-1ra) and IL-1 receptor (IL-1R) type I mRNA were related to embryonic development and IVF outcome. Blastomeres from 12 embryos were examined: beta-actin and IL-1R type I mRNA were detected in all blastomeres (100%) whereas IL-1beta could be detected in only nine of the blastomeres (75%). IL-1ra was expressed in only two (17%) of the blastomeres and those were simultaneously positive for IL-1beta. Both IL-1ra positive embryos were arrested in development before reaching blastocyst stage. Five embryos (three of them IL-1beta mRNA positive and two IL-1beta mRNA negative) were transferred as blastocysts; none of the transfers resulted in a pregnancy. We postulate that embryos expressing IL-1ra mRNA in a detectable amount appear more likely to be arrested in early developmental stages.

Quantitative gonadotropin-releasing hormone gene expression and immunohistochemical localization in human endometrium throughout the menstrual cycle.

GnRH is one of the paracrine/autocrine regulators of hCG secretion produced by the human trophoblast during pregnancy. We hypothesized that GnRH may play a role in the embryonic/endometrial dialogue during early implantation. To examine this hypothesis, we assessed GnRH and GnRH-receptor mRNA and protein expression in human endometrium throughout the menstrual cycle of premenopausal fertile patients. Quantitation of the mRNA was performed by reverse transcription (RT)-competitive polymerase chain reaction (PCR) in the presence of a competitive cDNA fragment. RT-PCR revealed that unfractioned endometrium and isolated endometrial stromal and epithelial cells express GnRH and GnRH-receptor mRNA throughout all phases of the menstrual cycle. Quantitative PCR showed a dynamic pattern in the GnRH mRNA expression throughout the cycle, with a significant increase (p < 0.05) in the secretory phase as compared to the proliferative phase. Furthermore, quantitative competitive PCR of isolated glandular and stromal cells showed higher mRNA levels (p < 0.05) in the luteal phase in both compartments. GnRH immunostaining was localized in all major compartments, with the most intense staining during the luteal phase. On the basis of these data, we suggest that during reproductive life, endometrial GnRH may play a paracrine/autocrine role in the early stages of implantation by modulating embryonic trophoblastic secretion of hCG.