Neonatal exposure to bisphenol A alters estrogen-dependent mechanisms governing sexual behavior in the adult female rat

Endocrine effect of phthalate metabolites and a butterfly effect of prenatal exposure to androgens on qualitative aspects of female sexual response- an initial survey

There is growing evidence that endocrine disruptive chemicals have deleterious effects on sexual and reproductive function. To examine subjective sexual functions in human females and their relationship to postnatal phthalate exposure and perinatal androgenization, a Sexuality Score (SS) was established from a first-stage survey questionnaire of subjective sexual function filled out by female university students (n = 68; average age 25.23 ± 5.17 years; rural 25.51 ± 6.74 vs. urban 25.85 ± 1.43 years). Seventeen phthalate metabolites in urine samples were analyzed by high-performance liquid chromatography (HPLC) and tandem mass spectrometry (MS/MS). Females were also assessed for the 2D:4D digit ratio as an index of perinatal androgenization. The mean age of menarche was 12.82 ± 1.35 years (rural 12.59 ± 1.39 vs. urban 13.18 ± 1.27; p = 0.01). The mean age at first sexual intercourse was 14.88 ± 6.89 years (rural 14.62 ± 7.20 vs. urban 15.24 ± 6.55), and as the age of first sexual intercourse increases, the SS score tends to increase as well, albeit moderately (r = 0.25, p = 0.037). Mono-iso-butyl phthalate, mono(2-ethyl-5-carboxypentyl) phthalate, mono(hydroxy-n-butyl) phthalate, mono(2-ethyl-5-oxohexyl) phthalate (p ≤ 0.05) and mono(2-carboxymethylhexyl) phthalate (p ≤ 0.01) were negatively associated with SS. A compounding butterfly effect of prenatal exposure to androgens was observed with disruptive effects of mono(2-ethyl-5-oxohexyl) phthalate and mono(2-ethyl-5-carboxypentyl) phthalate on sexual function. Exposure to phthalates in adult females may lead to disruption of subjective sexual function, especially concerning sexual desire and sexual satisfaction, and perinatal androgenization could augment these effects.

Imprinting and Reproductive Health: A Toxicological Perspective

This overview discusses the role of imprinting in the development of an organism, and how exposure to environmental chemicals during fetal development leads to the physiological and biochemical changes that can have adverse lifelong effects on the health of the offspring. There has been a recent upsurge in the use of chemical products in everyday life. These chemicals include industrial byproducts, pesticides, dietary supplements, and pharmaceutical products. They mimic the natural estrogens and bind to estradiol receptors. Consequently, they reduce the number of receptors available for ligand binding. This leads to a faulty signaling in the neuroendocrine system during the critical developmental process of 'imprinting'. Imprinting causes structural and organizational differentiation in male and female reproductive organs, sexual behavior, bone mineral density, and the metabolism of exogenous and endogenous chemical substances. Several studies conducted on animal models and epidemiological studies provide profound evidence that altered imprinting causes various developmental and reproductive abnormalities and other diseases in humans. Altered metabolism can be measured by various endpoints such as the profile of cytochrome P-450 enzymes (CYP450's), xenobiotic metabolite levels, and DNA adducts. The importance of imprinting in the potentiation or attenuation of toxic chemicals is discussed.

Environmental pollution, a hidden culprit for health issues

The environmental and health impacts from the massive discharge of chemicals and subsequent pollution have been gaining increasing public concern. The unintended exposure to different pollutants, such as heavy metals, air pollutants and organic chemicals, may cause diverse deleterious effects on human bodies, resulting in the incidence and progression of different diseases. The article reviewed the outbreak of environmental pollution-related public health emergencies, the epidemiological evidence on certain pollution-correlated health effects, and the pathological studies on specific pollutant exposure. By recalling the notable historical life-threatening disasters incurred by local chemical pollution, the damning evidence was presented to criminate certain pollutants as the main culprit for the given health issues. The epidemiological data on the prevalence of some common diseases revealed a variety of environmental pollutants to blame, such as endocrine-disrupting chemicals (EDCs), fine particulate matters (PMs) and heavy metals. The retrospection of toxicological studies provided illustrative clues for evaluating ambient pollutant-induced health risks. Overall, environmental pollution, as the hidden culprit, should answer for the increasing public health burden, and more efforts are highly encouraged to strive to explore the cause-and-effect relationships through extensive epidemiological and pathological studies.

Effects of endocrine-disrupting chemicals on hypothalamic oxytocin and vasopressin systems

Exposures to endocrine disrupting chemicals (EDCs) perturb hormonal systems. EDCs are particularly problematic when exposure happens in the fetus and infant due to the high sensitivity of developing organisms to hormone actions. Previous work has shown that prenatal polychlorinated biphenyl (PCB) exposure disrupts hypothalamic development, reproductive physiology, mate preference behavior, and social behaviors in a sexually dimorphic manner. Based on evidence that EDCs perturb social behaviors in rodents, we examined effects of PCBs on the neuropeptides oxytocin (OXT) and vasopressin (AVP) that are involved in regulating these behaviors. Rats were exposed prenatally (gestational days 16 and 18) to the weakly estrogenic PCB mixture Aroclor 1221 (0.5 or 1 mg/kg), to estradiol benzoate (EB, a positive control), or to the vehicle (3% dimethyl sulfoxide). In adult (~P90) brains, we counted immunolabeled oxytocin and vasopressin cell numbers in the paraventricular nucleus (PVN) and supraoptic nucleus (SON) of the hypothalamus. EDCs did not change absolute numbers of oxytocin or vasopressin cells in either region, although there were some modest shifts in the rostral-caudal distribution. Second, expression of genes for these nonapeptides (Oxt, Avp), their receptors (Oxtr, Avpr1a), and the estrogen receptor beta (Esr2), was determined by qPCR. In the PVN, there were dose-dependent effects of PCBs in males (Oxt, Oxtr), and effects of EB in females (Avp, Esr2). In the SON, Oxt, and Esr2 were affected by treatments in males. These changes to protein and gene expression caused by prenatal treatments suggest that transcriptional and posttranscriptional mechanisms play roles in mediating how EDCs reprogram hypothalamic development.

Multi- and Transgenerational Outcomes of an Exposure to a Mixture of Endocrine-Disrupting Chemicals (EDCs) on Puberty and Maternal Behavior in the Female Rat

BACKGROUND

The effects of endocrine-disrupting chemicals (EDCs) on fertility and reproductive development represent a rising concern in modern societies. Although the neuroendocrine control of sexual maturation is a major target of EDCs, little is known about the potential role of the hypothalamus in puberty and ovulation disruption transmitted across generations.

OBJECTIVES

We hypothesized that developmental exposure to an environmentally relevant dose of EDC mixture could induce multi- and/or transgenerational alterations of sexual maturation and maternal care in female rats through epigenetic reprograming of the hypothalamus. We investigated the transmission of a disrupted reproductive phenotype via the maternal germline or via nongenomic mechanisms involving maternal care.

METHODS

Adult female Wistar rats were exposed prior to and during gestation and until the end of lactation to a mixture of the following 13 EDCs: di-n-butyl phthalate (DnBP), di(2-ethylhexyl) phthalate (DEHP), bisphenol A (BPA), vinclozolin, prochloraz, procymidone, linuron, epoxynaxole, dichlorodiphenyldichloroethylene, octyl methoxynimmate, 4-methylbenzylidene camphor (4-MBC), butylparaben, and acetaminophen. Perinatally exposed offspring (F1) were mated with unexposed males to generate germ cell (F2) and transgenerationally exposed (F3 and F4) females. Sexual maturation, maternal behavior, and hypothalamic targets of exposure were studied across generations.

RESULTS

Germ cell (F2) and transgenerationally (F3) EDC-exposed females, but not F1, displayed delayed pubertal onset and altered folliculogenesis. We reported a transgenerational alteration of key hypothalamic genes controlling puberty and ovulation (Kiss1, Esr1, and Oxt), and we identified the hypothalamic polycomb group of epigenetic repressors as actors of this mechanism. Furthermore, we found a multigenerational reduction of maternal behavior (F1-F3) induced by a loss in hypothalamic dopaminergic signaling. Using a cross-fostering paradigm, we identified that the reduction in maternal phenotype was normalized in EDC-exposed pups raised by unexposed dams, but no reversal of the pubertal phenotype was achieved.

DISCUSSION

Rats developmentally exposed to an EDC mixture exhibited multi- and transgenerational disruption of sexual maturation and maternal care via hypothalamic epigenetic reprogramming. These results raise concerns about the impact of EDC mixtures on future generations. https://doi.org/10.1289/EHP8795.

EDCs Reorganize Brain-Behavior Phenotypic Relationships in Rats

All species, including humans, are exposed to endocrine-disrupting chemicals (EDCs). Previous experiments have shown behavioral deficits caused by EDCs that have implications for social competence and sexual selection. The neuromolecular mechanisms for these behavioral changes induced by EDCs have not been thoroughly explored. Here, we tested the hypothesis that EDCs administered to rats during a critical period of embryonic brain development would lead to the disruption of normal social preference behavior, and that this involves a network of underlying gene pathways in brain regions that regulate these behaviors. Rats were exposed prenatally to human-relevant concentrations of EDCs (polychlorinated biphenyls [PCBs], vinclozolin [VIN]), or vehicle. In adulthood, a sociosexual preference test was administered. We profiled gene expression of in preoptic area, medial amygdala, and ventromedial nucleus. Prenatal PCBs impaired sociosexual preference in both sexes, and VIN disrupted this behavior in males. Each brain region had unique sets of genes altered in a sex- and EDC-specific manner. The effects of EDCs on individual traits were typically small, but robust; EDC exposure changed the relationships between gene expression and behavior, a pattern we refer to as dis-integration and reconstitution. These findings underscore the effects that developmental exposure to EDCs can have on adult social behavior, highlight sex-specific and individual variation in responses, and provide a foundation for further work on the disruption of genes and behavior after prenatal exposure to EDCs.

Cellular and molecular features of EDC exposure: consequences for the GnRH network

The onset of puberty and the female ovulatory cycle are important developmental milestones of the reproductive system. These processes are controlled by a tightly organized network of neurotransmitters and neuropeptides, as well as genetic, epigenetic and hormonal factors, which ultimately drive the pulsatile secretion of gonadotropin-releasing hormone. They also strongly depend on organizational processes that take place during fetal and early postnatal life. Therefore, exposure to environmental pollutants such as endocrine-disrupting chemicals (EDCs) during critical periods of development can result in altered brain development, delayed or advanced puberty and long-term reproductive consequences, such as impaired fertility. The gonads and peripheral organs are targets of EDCs, and research from the past few years suggests that the organization of the neuroendocrine control of reproduction is also sensitive to environmental cues and disruption. Among other mechanisms, EDCs interfere with the action of steroidal and non-steroidal receptors, and alter enzymatic, metabolic and epigenetic pathways during development. In this Review, we discuss the cellular and molecular consequences of perinatal exposure (mostly in rodents) to representative EDCs with a focus on the neuroendocrine control of reproduction, pubertal timing and the female ovulatory cycle.

The effects of 28-day early-life exposure to triphenyl phosphate (TPhP) on odor preference and sexual behavior in female rats

Many chemical substances are detectable in house dust, and they are consequently taken into our bodies via the mouth and nose. Triphenyl phosphate (TPhP), a flame retardant that has an estrogen‐like effect in vitro, is present in house dust at high concentrations. Estrogen exposure during development has significant influences on reproductive behavior in rodents, and its effects persist until maturity. In the present study, we investigated the effect of early life exposure to TPhP on the reproductive behavior of female rats. Oral treatment with TPhP (25 or 250 mg/kg), ethinyl estradiol (EE; 15 μg/kg) as a positive control, or sesame oil as a negative control, were given to female rats (from birth to 28 days of age). The 8‐week‐old rats were bilaterally ovariectomized. At 12–15 weeks of age, the rats were subjected to odor preference and sexual behavior tests. In the odor preference test, the oil group showed significantly higher preference for male odor than female odor, but the low‐dose TPhP treatment group lost the preference for male odor, indicating a possible outcome of early life TPhP exposure on sexual recognition. In the sexual behavior test, both the EE and TPhP treatment groups displayed significantly less proceptive behavior. These results suggest that early life exposure to TPhP disturbs the normal sexual behavior of female rats.

Triphenyl phosphate (TPhP) is a flame retardant detected in house dust at high concentrations. TPhP exhibits estrogenic effect in vitro; however, its effect remains unclear in vivo. We examined the effects of early life exposure to low (25 mg/kg) and high (250 mg/kg) doses of TPhP in female rats on reproductive behavior. In the case of sexual behavior, TPhP significantly reduced proceptive behavior. This study showed that early life exposure to TPhP disturbs the normal sexual behavior of female rats.

Glyphosate-based herbicide induces hyperplastic ducts in the mammary gland of aging Wistar rats

Glyphosate-based herbicide (GBH) exposure is known to have adverse effects on endocrine-related tissues. Here, we aimed to determine whether early postnatal exposure to a GBH induces long-term effects on the rat mammary gland. Thus, female Wistar pups were injected with saline solution (Control) or GBH (2 mg glyphosate/kg/day) on postnatal days (PND) 1, 3, 5 and 7. At 20 months of age, mammary gland samples were collected to determine histomorphological features, proliferation index and the expression of steroid hormone receptors expression, by immunohistochemistry, and serum samples were collected to assess 17β-estradiol (E2) and progesterone (P4) levels. GBH exposure induced morphological changes evidenced by a higher percentage of hyperplastic ducts and a fibroblastic-like stroma in the mammary gland. GBH-treated rats also showed a high expression of steroid hormone receptors in hyperplastic ducts. The results indicate that early postnatal exposure to GBH induces long-term alterations in the mammary gland morphology of aging female rats.

Perinatal exposure to bisphenol A (BPA) impairs neuroendocrine mechanisms regulating food intake and kisspetin system in adult male rats. Evidences of metabolic disruptor hypothesis

Bisphenol A (BPA) is a compound used in the polymerization of plastic polycarbonates. It is an endocrine disruptor and it has been postulated to be an obesogen. Our objective was to determine the influence of perinatal exposure to BPA on body weight, hormone levels, metabolic parameters and hypothalamic signals that regulate food intake and kisspeptin system in adult male rats. Male rats were exposed to 50 μg/kg/day of BPA or vehicle from day 9 of gestation to weaning in the drinking water. Since weaning, they were fed with control or high fat diet for 20 weeks. Perinatal exposure to BPA impaired glucose homeostasis, induced obesity and increased food intake in adult male rats altering hypothalamic signals, partially mimicking and/or producing an exacerbation of the effects of feeding fat diet. We also observed an increase in kisspeptin expression by BPA exposure. Evidences shown in this work support the metabolic disruptor hypothesis for BPA.

Consensus on the key characteristics of endocrine-disrupting chemicals as a basis for hazard identification

Endocrine-disrupting chemicals (EDCs) are exogenous chemicals that interfere with hormone action, thereby increasing the risk of adverse health outcomes, including cancer, reproductive impairment, cognitive deficits and obesity. A complex literature of mechanistic studies provides evidence on the hazards of EDC exposure, yet there is no widely accepted systematic method to integrate these data to help identify EDC hazards. Inspired by work to improve hazard identification of carcinogens using key characteristics (KCs), we have developed ten KCs of EDCs based on our knowledge of hormone actions and EDC effects. In this Expert Consensus Statement, we describe the logic by which these KCs are identified and the assays that could be used to assess several of these KCs. We reflect on how these ten KCs can be used to identify, organize and utilize mechanistic data when evaluating chemicals as EDCs, and we use diethylstilbestrol, bisphenol A and perchlorate as examples to illustrate this approach.

Endocrine-disrupting chemicals: Effects on neuroendocrine systems and the neurobiology of social behavior

A contribution to SBN/ICN special issue. Endocrine-disrupting chemicals (EDCs) are pervasive in the environment. They are found in plastics and plasticizers (bisphenol A (BPA) and phthalates), in industrial chemicals such as polychlorinated biphenyls (PCBs), and include some pesticides and fungicides such as vinclozolin. These chemicals act on hormone receptors and their downstream signaling pathways, and can interfere with hormone synthesis, metabolism, and actions. Because the developing brain is particularly sensitive to endogenous hormones, disruptions by EDCs can change neural circuits that form during periods of brain organization. Here, we review the evidence that EDCs affect developing hypothalamic neuroendocrine systems, and change behavioral outcomes in juvenile, adolescent, and adult life in exposed individuals, and even in their descendants. Our focus is on social, communicative and sociosexual behaviors, as how an individual behaves with a same- or opposite-sex conspecific determines that individual's ability to exist in a community, be selected as a mate, and reproduce successfully.

Evidence-based adverse outcome pathway approach for the identification of BPA as en endocrine disruptor in relation to its effect on the estrous cycle

Proper cyclicity is essential to reach successful optimal fertility. In rats and mice, BPA exposure is repeatedly and reliably reported to show an adverse effect on the estrous cycle after exposures at different life stages. In humans, a possible association between modifications of menstrual cycle characteristics (e.g. length of the cycle, duration of menstrual bleeding) and sub-fecundity or spontaneous abortion has been observed. Alterations of ovarian cyclicity can therefore be definitely considered as an adverse health outcome. As a prerequisite for the EU REACH regulation to identify a substance as an endocrine disruptor and a SVHC,¹ the proof has to be established that the substance can have deleterious health effects resulting from an endocrine mode of action. This review provides an overview of the currently available data allowing to conclude that the adverse effects of BPA exposure on ovarian cyclicity is mediated by an endocrine mode of action.

Glyphosate-based herbicide enhances the uterine sensitivity to estradiol in rats

In a previous work, we detected that postnatal exposure to a glyphosate-based herbicide (GBH) alters uterine development in prepubertal rats causing endometrial hyperplasia and increasing cell proliferation. Our goal was to determine whether exposure to low dose of a GBH during postnatal development might enhance the sensitivity of the uterus to an estrogenic treatment. Female Wistar pups were subcutaneously injected with saline solution (control) or GBH using the reference dose (2 mg/kg/day, EPA) on postnatal days (PND) 1, 3, 5 and 7. At weaning (PND21), female rats were bilaterally ovariectomized and treated with silastic capsules containing 17β-estradiol (E2, 1 mg/mL) until they were 2 months of age. On PND60, uterine samples were removed and processed for histology, immunohistochemistry and mRNA extraction to evaluate: (i) uterine morphology, (ii) uterine cell proliferation by the detection of Ki67, (iii) the expression of the estrogen receptors alpha (ESR1) and beta (ESR2) and (iv) the expression of WNT7A and CTNNB1. GBH-exposed animals showed increased luminal epithelial height and stromal nuclei density. The luminal and glandular epithelium were markedly hyperplastic in 43% of GBH-exposed animals. GBH exposure caused an increase in E2-induced cell proliferation in association with an induction of both ESR1 and ESR2. GBH treatment decreased membranous and cytoplasmic expression of CTNNB1 in luminal and glandular epithelial cells and increased WNT7A expression in the luminal epithelium. These results suggest that early postnatal exposure to a GBH enhances the sensitivity of the rat uterus to estradiol and induces histomorphological and molecular changes associated with uterine hyperplasia.

Sexual Behavior: From Hormonal Regulation to Endocrine Disruption

Sexual behavior constitutes a chain of behavioral responses beginning with courtship and leading to copulation. These responses, which are exhibited in a sexually dimorphic manner by the two partners, are tightly regulated by sex steroid hormones as early as the perinatal period. Hormonal changes or exposure to exogenous factors exhibiting hormone-mimetic activities, such as endocrine disrupting compounds (EDC), can therefore interfere with their expression. Here we review the experimental studies in rodents performed to address the potential effects of exposure to EDC on sexual behavior and underlying mechanisms, with particular attention to molecules with estrogenic and/or anti-androgenic activities.

Effects of perinatal bisphenol A exposure on the volume of sexually-dimorphic nuclei of juvenile rats: A CLARITY-BPA consortium study

Bisphenol A (BPA) is a high volume endocrine disrupting chemical found in a wide variety of products including plastics and epoxy resins. Human exposure is nearly ubiquitous, and higher in children than adults. Because BPA has been reported to interfere with sex steroid hormone signaling, there is concern that developmental exposure, even at levels below the current FDA No Observed Adverse Effect Level (NOAEL) of 5mg/kg body weight (bw)/day, can disrupt brain sexual differentiation. The current studies were conducted as part of the CLARITY-BPA (Consortium Linking Academic and Regulatory Insights on BPA Toxicity) program and tested the hypothesis that perinatal BPA exposure would induce morphological changes in hormone sensitive, sexually dimorphic brain regions. Sprague-Dawley rats were randomly assigned to 5 groups: BPA (2.5, 25, or 2500μg/kgbw/day), a reference estrogen (0.5μg ethinylestradiol (EE₂)/kgbw/day), or vehicle. Exposure occurred by gavage to the dam from gestational day 6 until parturition, and then to the offspring from birth through weaning. Unbiased stereology was used to quantify the volume of the sexually dimorphic nucleus (SDN), the anteroventral periventricular nucleus (AVPV), the posterodorsal portion of the medial amygdala (MePD), and the locus coeruleus (LC) at postnatal day 28. No appreciable effects of BPA were observed on the volume of the SDN or LC. However, AVPV volume was enlarged in both sexes, even at levels below the FDA NOAEL. Collectively, these data suggest the developing brain is vulnerable to endocrine disruption by BPA at exposure levels below previous estimates by regulatory agencies.

Detection and activity of 11 beta hydroxylase (CYP11B1) in the bovine ovary

Glucocorticoids (GCs) such as cortisol and corticosterone are important steroid hormones with different functions in intermediate metabolism, development, cell differentiation, immune response and reproduction. In response to physiological and immunological stress, adrenocorticotropic hormone (ACTH) acts on the adrenal gland by stimulating the synthesis and secretion of GCs. However, there is increasing evidence that GCs may also be synthesized by extra-adrenal tissues. Here, we examined the gene and protein expression of the enzyme 11β-hydroxylase P450c11 (CYP11B1), involved in the conversion of 11-deoxycortisol to cortisol, in the different components of the bovine ovary and determined the functionality of CYP11B1in vitro.CYP11B1mRNA was expressed in granulosa and theca cells in small, medium and large antral ovarian follicles, and CYP11B1 protein was expressed in medium and large antral follicles. After stimulation by ACTH, we observed an increased secretion of cortisol by the wall of large antral follicles. We also observed a concentration-dependent decrease in the concentration of cortisol in response to metyrapone, an inhibitor of CYP11B1. This decrease was significant at 10−5 µM metyrapone. In conclusion, this study demonstrated for the first time the presence of CYP11B1 in the bovine ovary. This confirms that there could be a local synthesis of GCs in the bovine ovary and therefore a potential endocrine responder to stress through these hormones.

Effects of neonatal 17α-ethinyloestradiol exposure on female-paced mating behaviour in the rat

Correct perinatal oestrogen levels are critical for sexual differentiation. For example, perinatal exposure to oestrogen causes masculinization and defeminization of the brain in female rats and also induces delayed effects after maturation characterized by early onset of abnormal oestrus cycling. However, the mechanisms underlying the above effects of oestrogen remain to be fully determined. 17α-ethinyloestradiol (EE), a common synthetic oestrogen widely used in oral contraceptives, binds specifically to oestrogen receptors. In this study, we demonstrated the effects of a single neonatal injection of high- or low-dose EE on reproductive behaviours. Female rats within 24 h after birth were subcutaneously injected with sesame oil, EE (0.02, 2 mg kg^-1 ) and 17β-oestradiol (E₂ ) (20 mg kg^-1 ). Between 11 and 15 weeks of age, sexual behaviour was tested twice in a paced mating situation. Latency to enter, lordosis and soliciting behaviour were recorded. Both high-dose EE- and E₂ -treated females showed a significantly lower lordosis quotient, decreased soliciting behaviours, increased rejection and fighting numbers. Accessibility to males was also delayed by neonatal E₂ exposure, although it was shortened by high-dose EE exposure. In contrast, low-dose EE-treated females did not exhibit impaired sexual behaviour. These results suggest that single neonatal exposure to a high dose of EE or E₂ disturbs the normal development of the female brain, resulting in impaired sexual behaviours in a female-paced mating situation. Besides, the differences noted between high-dose EE- and E₂ -treated females might be caused by different affinities of the oestrogen receptors, metabolic rates or mechanisms of action. Copyright © 2017 John Wiley & Sons, Ltd.

Effects of neonatal exposure to a glyphosate-based herbicide on female rat reproduction

In this study, we investigated whether neonatal exposure to a glyphosate-based herbicide (GBH) alters the reproductive performance and the molecular mechanisms involved in the decidualization process in adult rats. Newborn female rats received vehicle or 2 mg/kg/day of a GBH on postnatal days (PND) 1, 3, 5 and 7. On PND90, the rats were mated to evaluate (i) the reproductive performance on gestational day (GD) 19 and (ii) the ovarian steroid levels, uterine morphology, endometrial cell proliferation, apoptosis and cell cycle regulators, and endocrine pathways that regulate uterine decidualization (steroid receptors/COUP-TFII/Bmp2/Hoxa10) at the implantation sites (IS) on GD9. The GBH-exposed group showed a significant increase in the number of resorption sites on GD19, associated with an altered decidualization response. In fact, on GD9, the GBH-treated rats showed morphological changes at the IS, associated with a decreased expression of estrogen and progesterone receptors, a downregulation of COUP-TFII (Nr2f2) and Bmp2 mRNA and an increased expression of HOXA10 and the proliferation marker Ki67(Mki67) at the IS. We concluded that alterations in endometrial decidualization might be the mechanism of GBH-induced post-implantation embryo loss.

EDC-2: The Endocrine Society's Second Scientific Statement on Endocrine-Disrupting Chemicals

The Endocrine Society's first Scientific Statement in 2009 provided a wake-up call to the scientific community about how environmental endocrine-disrupting chemicals (EDCs) affect health and disease. Five years later, a substantially larger body of literature has solidified our understanding of plausible mechanisms underlying EDC actions and how exposures in animals and humans-especially during development-may lay the foundations for disease later in life. At this point in history, we have much stronger knowledge about how EDCs alter gene-environment interactions via physiological, cellular, molecular, and epigenetic changes, thereby producing effects in exposed individuals as well as their descendants. Causal links between exposure and manifestation of disease are substantiated by experimental animal models and are consistent with correlative epidemiological data in humans. There are several caveats because differences in how experimental animal work is conducted can lead to difficulties in drawing broad conclusions, and we must continue to be cautious about inferring causality in humans. In this second Scientific Statement, we reviewed the literature on a subset of topics for which the translational evidence is strongest: 1) obesity and diabetes; 2) female reproduction; 3) male reproduction; 4) hormone-sensitive cancers in females; 5) prostate; 6) thyroid; and 7) neurodevelopment and neuroendocrine systems. Our inclusion criteria for studies were those conducted predominantly in the past 5 years deemed to be of high quality based on appropriate negative and positive control groups or populations, adequate sample size and experimental design, and mammalian animal studies with exposure levels in a range that was relevant to humans. We also focused on studies using the developmental origins of health and disease model. No report was excluded based on a positive or negative effect of the EDC exposure. The bulk of the results across the board strengthen the evidence for endocrine health-related actions of EDCs. Based on this much more complete understanding of the endocrine principles by which EDCs act, including nonmonotonic dose-responses, low-dose effects, and developmental vulnerability, these findings can be much better translated to human health. Armed with this information, researchers, physicians, and other healthcare providers can guide regulators and policymakers as they make responsible decisions.

Neonatal exposure to xenoestrogens impairs the ovarian response to gonadotropin treatment in lambs

Bisphenol A (BPA) and diethylstilbestrol (DES) are xenoestrogens, which have been associated with altered effects on reproduction. We hypothesized that neonatal xenoestrogen exposure affects the ovarian functionality in lambs. Thus, we evaluated the ovarian response to exogenous ovine FSH (oFSH) administered from postnatal day 30 (PND30) to PND32 in female lambs previously exposed to low doses of DES or BPA (BPA50: 50 μg/kg per day, BPA0.5: 0.5 μg/kg per day) from PND1 to PND14. We determined: i) follicular growth, ii) circulating levels of 17β-estradiol (E2), iii) steroid receptors (estrogen receptor alpha, estrogen receptor beta, and androgen receptor (AR)) and atresia, and iv) mRNA expression levels of the ovarian bone morphogenetic protein (BMPs) system (BMP6, BMP15, BMPR1B, and GDF9) and FSH receptor (FSHR). Lambs neonatally exposed to DES or BPA showed an impaired ovarian response to oFSH with a lower number of follicles ≥2 mm in diameter together with a lower number of atretic follicles and no increase in E2 serum levels in response to oFSH treatment. In addition, AR induction by oFSH was disrupted in granulosa and theca cells of lambs exposed to DES or BPA. An increase in GDF9 mRNA expression levels was observed in oFSH-primed lambs previously treated with DES or BPA50. In contrast, a decrease in BMPR1B was observed in BPA0.5-postnatally exposed lambs. The modifications in AR, GDF9, and BMPR1B may be associated with the altered ovarian function due to neonatal xenoestrogen exposure in response to an exogenous gonadotropin stimulus. These alterations may be the pathophysiological basis of subfertility syndrome in adulthood.

Bisphenol A and phthalate endocrine disruption of parental and social behaviors

Perinatal exposure to endocrine disrupting chemicals (EDCs) can induce promiscuous neurobehavioral disturbances. Bisphenol A and phthalates are two widely prevalent and persistent EDCs reported to lead to such effects. Parental and social behaviors are especially vulnerable to endocrine disruption, as these traits are programmed by the organizational-activational effects of testosterone and estrogen. Exposure to BPA and other EDCs disrupts normal maternal care provided by rodents and non-human primates, such as nursing, time she spends hunched over and in the nest, and grooming her pups. Paternal care may also be affected by BPA. No long-term study has linked perinatal exposure to BPA or other EDC and later parental behavioral deficits in humans. The fact that the same brain regions and neural hormone substrates govern parental behaviors in animal models and humans suggests that this suite of behaviors may also be vulnerable in the latter. Social behaviors, such as communication, mate choice, pair bonding, social inquisitiveness and recognition, play behavior, social grooming, copulation, and aggression, are compromised in animal models exposed to BPA, phthalates, and other EDCs. Early contact to these chemicals is also correlated with maladaptive social behaviors in children. These behavioral disturbances may originate by altering the fetal or adult gonadal production of testosterone or estrogen, expression of ESR1, ESR2, and AR in the brain regions governing these behaviors, neuropeptide/protein hormone (oxytocin, vasopressin, and prolactin) and their cognate neural receptors, and/or through epimutations. Robust evidence exists for all of these EDC-induced changes. Concern also exists for transgenerational persistence of such neurobehavioral disruptions. In sum, evidence for social and parental deficits induced by BPA, phthalates, and related chemicals is strongly mounting, and such effects may ultimately compromise the overall social fitness of populations to come.

Neonatal exposure to low doses of endosulfan induces implantation failure and disrupts uterine functional differentiation at the pre-implantation period in rats

We investigated whether neonatal exposure to low doses of endosulfan affects fertility and uterine functional differentiation at pre-implantation in rats. Newborn female rats received the vehicle, 0.2 µg/kg/d of diethylstilbestrol (DES), 6 µg/kg/d of endosulfan (Endo6) or 600 µg/kg/d of endosulfan (Endo600) on postnatal days (PND) 1, 3, 5, and 7. On PND90, the rats were mated to evaluate their reproductive performance on gestational day (GD) 19 and their ovarian steroid serum levels, endometrial proliferation and implantation-associated proteins on GD5. DES and endosulfan decreased the pregnancy rate and the number of implantation sites. On GD5, DES and endosulfan did not change the serum levels of 17β-estradiol (E2) and progesterone (P); the endometrial proliferation decreased, which was associated with silencing of Hoxa10 in the Endo600-treated rats. Both doses of endosulfan increased the progesterone receptor (PR) expression, whereas the higher dose led additionally to an increase in estrogen receptor alpha (ERα). In the Endo600-treated rats, the down-regulation of Hoxa10 was associated with a deregulation of the steroid receptor coregulators. Alterations in endometrial proliferation and the endocrine pathway of Hoxa10/steroid receptors/coregulators might be the mechanism of endosulfan-induced implantation failure.

Mitochondrial dysfunction in early life resulted from perinatal bisphenol A exposure contributes to hepatic steatosis in rat offspring

An emerging literature suggests that bisphenol A (BPA), a widespread endocrine disrupting chemical, when exposure occurs in early life, may increase the risk of metabolic syndrome. In this study, we investigated the hypothesis that perinatal exposure to BPA predisposed offspring to fatty liver disease: the hepatic manifestation of metabolic syndrome, and its possible mechanism. Pregnant Wistar rats were administered with BPA (40μg/kg/day) or vehicle during gestation and lactation. Liver histology, biochemical analysis, transcriptome, and mitochondrial function were examined in male offspring at postnatal 3, 15 and 26 weeks. At 3 weeks of age, abnormal liver morphology and function were not observed in the BPA-exposed offspring, but a decrease in mitochondrial respiratory complex (MRC) activity (I and III) and significant changes in gene expression involved in mitochondrial fatty acid metabolism were observed compared with controls. At 15 weeks, micro-vesicular steatosis in liver, up-regulated genes involved in lipogenesis pathways, increased ROS generation and Cytc release were observed in the BPA-exposed offspring. Then, extensive fatty accumulation in liver and elevated serum ALT were observed in BPA-exposed offspring at 26 weeks. In the longitudinal observation, hepatic mitochondrial function including MRC activity, ATP production, ROS generation and mitochondrial membrane potential were progressively worsened in the BPA-exposed offspring. Perinatal BPA exposure contributes to the development of hepatic steatosis in the offspring of rats, which may be mediated through impaired hepatic mitochondrial function and up-regulated hepatic lipid metabolism.

Neuroendocrine and behavioral effects of maternal exposure to oral bisphenol A in female mice

Bisphenol A (BPA) is a widespread estrogenic compound. We investigated the effects of maternal exposure to BPA at reference doses on sexual behavior and neuroendocrine functions of female offspring in C57BL/6J mice. The dams were orally exposed to vehicle alone or vehicle-containing BPA at doses equivalent to the no observed adverse effect level (5 mg/kg body weight per day) and tolerable daily intake (TDI, 0.05 mg/kg body weight per day) level from gestational day 15 until weaning. Developmental exposure to BPA increased the lordosis quotient in naive females exposed to BPA at the TDI dose only. BPA exposure had no effect on olfactory preference, ability to express masculine behaviors or number of calbindin-positive cells, a sexually dimorphic population of the preoptic area. BPA at both doses selectively increased kisspeptin cell number in the preoptic periventricular nucleus of the rostral periventricular area of the third ventricle in adult females. It did not affect the number of GNRH-positive cells or percentage of kisspeptin appositions on GNRH neurons in the preoptic area. These changes were associated with higher levels of estradiol (E2) at the TDI dose while levels of LH, estrus cyclicity, ovarian and uterine weights, and fertility remained unaffected. Delay in the time of vaginal opening was observed during the postnatal period at TDI dose, without any alteration in body growth. This shows that developmental exposure to BPA at reference doses did not masculinize and defeminize the neural circuitry underlying sexual behavior in female mice. The TDI dose specifically exacerbated responses normally induced by ovarian E2, through estrogen receptor α, during the postnatal/prepubertal period.

Long-lasting effects of neonatal bisphenol A exposure on the implantation process

Successful implantation is the result of complex molecular interactions between the hormonally primed uterus and a mature blastocyst. This very carefully synchronized interplay of hormonal signals and feedback loops is potentially vulnerable to chemicals such as endocrine disruptors that may disrupt endocrine signaling. Bisphenol A (BPA) is one of the highest-volume chemicals produced worldwide. This chapter describes the effects of brief postnatal exposure to BPA on female reproductive performance and specifically on the uterine adaptations during the preimplantation period. We propose that an early alteration in Hoxa10 gene expression affects the functional differentiation of the preimplantation uterus as part of an altered endocrine signal transduction pathway. These molecular alterations could explain, at least in part, the adverse effects of BPA on uterine implantation. Exposure to endocrine disruptors, such as BPA, could contribute to the impaired female fertility noted over the past decades.

Cryptic confounding compounds: A brief consideration of the influences of anthropogenic contaminants on courtship and mating behavior

Contaminants, like pesticides, polychlorinated biphenyls (PCBs), dioxins and metals, are persistent and ubiquitous and are known to threaten the environment. Traditionally, scientists have considered the direct physiological risks that these contaminants pose. However, scientists have just begun to integrate ethology and toxicology to investigate the effects that contaminants have on behavior. This review considers the potential for contaminant effects on mating behavior. Here we assess the growing body of research concerning disruptions in sexual differentiation, courtship, sexual receptivity, arousal, and mating. We discuss the implications of these disruptions on conservation efforts and highlight the importance of recognizing the potential for environmental stressors to affect behavioral experimentation. More specifically, we consider the negative implications for anthropogenic contaminants to affect the immediate behavior of animals, and their potential to have cascading and/or long-term effects on the behavioral ecology and evolution of populations. Overall, we aim to raise awareness of the confounding influence that contaminants can have, and promote caution when interpreting results where the potential for cryptic affects are possible.

Perinatal exposure to bisphenol A enhances contextual fear memory and affects the serotoninergic system in juvenile female mice

Perinatal exposure to bisphenol A (BPA), an endocrine-disrupting chemical, affects the central nervous system, including effects on emotional responses and neurotransmitter release. In this study, we investigated the effects of BPA (250 ng/kg/day, from gestational day 10 to postnatal day 20) on fear memory and serotonin (5-HT) metabolites in the brain using contextual fear conditioning (FC) and high-performance liquid chromatography (HPLC), respectively, in adult and juvenile mice of both sexes. Furthermore, we studied the effects of BPA on the gene expression of 5-HT metabolite-related enzymes and 5-HT receptors using quantitative real-time RT PCR in the brains of juvenile females. BPA enhanced fear memory and increased serotonin metabolite (5-HIAA) levels and 5-HIAA/5-HT in the hippocampus, the striatum, the midbrain, the pons, and the medulla oblongata of juvenile female mice. In contrast, alterations in those areas were much smaller in adult females and in both juvenile and adult males. Furthermore, BPA induced increases in the expression levels of Tph2, Slc6a4, and Maoa mRNA in the hippocampus of juvenile females, indicating that BPA induces hyper 5-HT turnover in the hippocampus. Our results suggest that perinatal exposure to a low dose of BPA enhances fear memory and the 5-HTergic system in juvenile mice.

Alteration in localization of steroid hormone receptors and coregulatory proteins in follicles from cows with induced ovarian follicular cysts

Cystic ovarian disease (COD) is an important cause of infertility in cattle. The altered follicular dynamics and cellular differentiation observed in COD may be mediated through a disruption of the expression of steroid receptors and their associated transcriptional cofactors. The aim of this study was to determine the protein expression profiles of ESR1, ESR2, PGR, AR, NCOA3, NCOR2, and PHB2 (REA) in ovarian follicles in an experimental model of COD induced by the administration of ACTH. Ovaries were collected and follicles were dissected from heifers during the follicular phase (control) or from heifers treated with ACTH to induce the formation of ovarian follicular cysts. Ovaries were fixed, sectioned, and stained immunohistochemically for steroid receptors and the associated transcription factors. The relative expression of ESR1 was similar in follicular cysts and in tertiary follicles from both control and cystic cows and was significantly higher than in secondary follicles. The expression of ESR2 in the granulosa was higher in cystic follicles. No differences were seen for PGR. The expression of androgen receptor was significantly increased in tertiary follicles with lower immunostaining in cysts. The expression of NCOA3 was observed in the granulosa and theca with a significantly increased expression in the theca interna of cystic follicles. The highest levels of NCOR2 expression in granulosa, theca interna, and theca externa were observed in cysts. In granulosa cells, NCOR2 levels increase progressively as follicles mature and the treatment had no effect. In summary, ovaries from animals with induced COD exhibited altered steroid receptor expression compared with normal animals, as well as changes in the expression of their regulators. It is reasonable to suggest that in conditions characterized by altered ovulation and follicular persistence, such as COD, changes in the intra-ovarian expression of these proteins could play a role in their pathogenesis.

Neonatal injections of methoxychlor decrease adult rat female reproductive behavior

Methoxychlor (MXC), a commonly used pesticide, has been labeled as an endocrine disruptor. To evaluate the impact of neonatal exposure to MXC on female reproduction, female Sprague-Dawley rats were given subcutaneous injections on postnatal days 1, 3, and 5. The injections contained 1.0mg MXC, 2.0mg MXC, 10 μg 17β-estradiol benzoate (positive control), or sesame oil (vehicle). The injections of MXC had no effect on anogenital distance or day of vaginal opening. Treatment with either 2.0mg MXC or estradiol significantly increased the total number of days with vaginal keratinization. Treatment with MXC had no effect on ability to exhibit a mating response as an adult female, although the high dose MXC (2.0) and the positive control (estradiol) animals demonstrated a decrease in degree of receptivity, a decrease in proceptive behavior and an increase in rejection behavior. These data suggest that higher doses of MXC given directly to pups during the neonatal period can act as an estrogen and alter aspects of the nervous system, impacting adult reproductive characteristics.

One-step derivatization and preconcentration microextraction technique for determination of bisphenol A in beverage samples by gas chromatography-mass spectrometry

A simple technique based on ultrasound-assisted emulsification microextraction in situ derivatization (USAEME-ISD) is proposed for the one-step derivatization, extraction, and preconcentration of bisphenol A (BPA) in beverage samples prior to gas chromatography-mass spectrometry (GC-MS) analysis. BPA was in situ derivatized with acetic anhydride and simultaneously extracted and preconcentrated by using USAEME. Variables affecting the extraction efficiency of BPA were evaluated. Under optimal experimental conditions, the detection limit (LOD) was 38 ng L(-1) with a relative standard deviation (RSD) value of 11.6%. The linear working range was 100-1250 ng L(-1), and the coefficient of estimation (r(2)) of the calibration curve was ≥0.9971. The robustness of the proposed methodology was probed by developing a recovery study at two concentrations (125 and 500 ng L(-1)) over different beverage samples. This study led to a satisfactory result achieving recoveries of ≥82%, which showed acceptable robustness for determination of nanograms per liter of BPA in samples of food safety interest.

Sex differences in the neural circuit that mediates female sexual receptivity

Female sexual behavior in rodents, typified by the lordosis posture, is hormone-dependent and sex-specific. Ovarian hormones control this behavior via receptors in the hypothalamic ventromedial nucleus (VMH). This review considers the sex differences in the morphology, neurochemistry and neural circuitry of the VMH to gain insights into the mechanisms that control lordosis. The VMH is larger in males compared with females, due to more synaptic connections. Another sex difference is the responsiveness to estradiol, with males exhibiting muted, and in some cases reverse, effects compared with females. The lack of lordosis in males may be explained by differences in synaptic organization or estrogen responsiveness, or both, in the VMH. However, given that damage to other brain regions unmasks lordosis behavior in males, a male-typical VMH is unlikely the main factor that prevents lordosis. In females, key questions remain regarding the mechanisms whereby ovarian hormones modulate VMH function to promote lordosis.

Neonatal exposure to bisphenol A alters rat uterine implantation-associated gene expression and reduces the number of implantation sites

Endocrine disrupters have been associated with reproductive pathologies such as infertility and gynecological tumors. Using a rat model of early postnatal exposure to bisphenol A (BPA), we evaluated the long-term effects on 1) female reproductive performance, 2) uterine homeobox A10 (Hoxa10) and Hoxa10-target gene expression, and 3) ovarian steroid levels and uterine estrogen receptor α and progesterone (P) receptor expression. Newborn female rats received vehicle, BPA.05 (0.05 mg/kg · d), BPA20 (20 mg/kg · d), diethylstilbestrol.2 (0.2 μg/kg · d), or diethylstilbestrol 20 (20 μg/kg · d) on postnatal d 1, 3, 5, and 7. A significant decrease in the number of implantation sites was assessed in the xenoestrogen-exposed females. To address the molecular effects of postnatal xenoestrogen exposure on the pregnant uterus, we evaluated the expression of implantation-associated genes on d 5 of pregnancy (preimplantation uterus). All xenoestrogen-treated rats showed a lower expression of Hoxa10. In the same animals, two Hoxa10-downstream genes were misregulated in the uterus. β(3) Integrin, which is up-regulated by Hoxa10 in controls, was decreased, whereas empty spiracles homolog 2, which is down-regulated by Hoxa10, was increased. Furthermore a clear down-regulation of estrogen receptor α and P receptor expression was detected without changes in estradiol and P serum levels. The early exposure to BPA produced a lower number of implantation sites in association with a defective uterine environment during the preimplantation period. Alterations in the endocrine-regulated Hoxa10 gene pathways (steroid receptors--Hoxa10--β(3) integrin/empty spiracles homolog 2) could explain, at least in part, the BPA effects on the implantation process.

The role of Bisphenol A in shaping the brain, epigenome and behavior

Bisphenol A (BPA) is a xenoestrogen that was first synthesized in 1891. Its estrogenic properties were discovered in 1930, and shortly after that chemists identified its usefulness in the production of epoxy resins. Since the 1950s BPA has been used as a synthetic monomer in the manufacturing of polycarbonate plastic, polystyrene resins, and dental sealants. Roughly 6.5 billion pounds of BPA are produced each year and it is the major estrogenic compound that leaches into nearby water and food supplies (vom Saal et al., 2007). BPA has been detected in 95% of human urine samples, which indicates that environmental exposure is widespread (Calafat et al., 2005). Moreover, BPA affects reproductive tissues and the brain. Thus many studies have focused on the effects of BPA during embryonic development. The most recent FDA update (Administration January 2010) points to "some concern about the potential effects of Bisphenol A on the brain, behavior, and prostate gland in fetuses, infants, and young children." In light of this concern, we present an updated review of BPA's action on the brain and behavior. We begin with a discussion of BPA's role as both an endocrine active compound and an agent that alters DNA methylation. Next, we review publications that have reported effects of BPA on brain and behavior. We end with our interpretation of these data and suggestions for future research directions.

The impact of neonatal bisphenol-A exposure on sexually dimorphic hypothalamic nuclei in the female rat

Now under intense scrutiny, due to its endocrine disrupting properties, the potential threat the plastics component bisphenol-A (BPA) poses to human health remains unclear. Found in a multitude of polycarbonate plastics, food and beverage containers, and medical equipment, BPA is thought to bind to estrogen receptors (ERs), thereby interfering with estrogen-dependent processes. Our lab has previously shown that exposure to BPA (50mg/kg bw or 50μg/kg bw) during the neonatal critical period is associated with advancement of puberty, early reproductive senescence and ovarian malformations in female Long Evans rats. Here, using neural tissue obtained from the same animals, we explored the impact of neonatal BPA exposure on the development of sexually dimorphic hypothalamic regions critical for female reproductive physiology and behavior. Endpoints included quantification of oxytocin-immunoreactive neurons (OT-ir) in the paraventricular nucleus (PVN), serotonin (5-HT-ir) fiber density in the ventrolateral subdivision of the ventromedial nucleus (VMNvl) as well as ERα-ir neuron number in the medial preoptic area (MPOA), the VMNvl, and the arcuate nucleus (ARC). Both doses of BPA increased the number of OT-ir neurons within the PVN, but no significant effects were seen on 5-HT-ir fiber density or ERα-ir neuron number in any of the areas analyzed. In addition to hypothalamic development, we also assessed female sex behavior and body weight. No effect of BPA on sexual receptivity or proceptive behavior in females was observed. Females treated with BPA, however, weighed significantly more than control females by postnatal day 99. This effect of BPA on weight is critical because alterations in metabolism, are frequently associated with reproductive dysfunction. Collectively, the results of this and our prior study indicate that the impact of neonatal BPA exposure within the female rat hypothalamus is region specific and support the hypothesis that developmental BPA exposure may adversely affect reproductive development in females.

Developmental programming: impact of fetal exposure to endocrine-disrupting chemicals on gonadotropin-releasing hormone and estrogen receptor mRNA in sheep hypothalamus

Bisphenol-A (BPA) and methoxychlor (MXC), two endocrine-disrupting chemicals (EDCs) with estrogenic and antiandrogenic effects, disrupt the reproductive system. BPA has profound effects on luteinizing hormone (LH) surge amplitude, and MXC has profound effects on on LH surge timing in sheep. The neural mechanisms involved in the differential disruption of the LH surge by these two EDCs remain to be elucidated. We tested the hypothesis that the differential effects of BPA and MXC on LH surge system involved changes in hypothalamic gonadotropin-releasing hormone (GnRH) and estrogen receptors (ESR), ESR1 and ESR2, mRNA expression. Pregnant sheep were given daily injections of cottonseed oil (controls), MXC, or BPA (5mg/kg/day) from day 30 to 90 of gestation (term 147d). Offspring from these animals were euthanized as adults, during the late follicular phase following synchronization of estrus with prostaglandin F(2alpha), just before the expected onset of preovulatory LH surge and changes in mRNA expression of hypothalamic GnRH, ESR1, and ESR2 quantified following in situ hybridization. GnRH mRNA expression was significantly lower in both groups of EDC-treated females compared to controls. ESR1 expression was increased in prenatal BPA- but not MXC-treated females in medial preoptic area relative to controls. In contrast, ESR2 expression was reduced in the medial preoptic area of both EDC-treated groups. Differences in expression of ESR1/ESR2 receptors may contribute to the differential effects of BPA and MXC on the LH surge system. These findings provide support that prenatal exposure to EDCs alters the neural developmental trajectory leading to long-term reproductive consequences in the adult female.