Endocrine Disruption and Developmental Abnormalities of Female Reproduction

The developing organism is particularly sensitive to exposureto estrogenic chemicals during a critical period in the inductionof longterm changes in female reproductive organs, and persistentmolecular alterations induced by the perinatal estrogenic agents.The perinatal mouse model can be utilized as an indicator ofpossible longterm consequences of exposure to exogenous estrogeniccompounds including environmental endocrine disruptors. Attentionshould be paid to abnormalities in female genital organs exposedto estrogenic endocrine disruptors during fetal and early postnataldevelopment in mammals including humans.     

Endocrine Organs of a Parasitic Male Deep-Sea Angler-Fish,Edriolychnus schmidti

The parasitic male deep-sea angler-fish Edriolychnus schmidti Regan 1925, which was described by Regan and Trewavas 1932, was reinvestigated with respect to the endocrine organs. Although the original microscopical sections are not in a good condition, it could be concluded that those organs which are involved in regulation of various internal environmental factors, as well as those involved in adaption to external factors, appear poorly developed or reduced. Mechanisms regulating reproductive activities seem to be well developed; a pronounced tuberis region is seen in the otherwise reduced brain and the peculiar pituitary gland appears to contain secretory active cells.     

DNA methylation increases throughout Arabidopsis development

We used amplified fragment length polymorphisms (AFLP) to analyze the stability of DNA methylation throughout Arabidopsis development. AFLP can detect genome-wide changes in cytosine methylation produced by DNA demethylation agents, such as 5-azacytidine, or specific mutations at the DDM1 locus. In both cases, cytosine demethylation is associated with a general increase in the presence of amplified fragments. Using this approach, we followed DNA methylation at methylation sensitive restriction sites throughout Arabidopsis development. The results show a progressive DNA methylation trend from cotyledons to vegetative organs to reproductive organs.     

Fused lobed anther and hooked stigma affect pollination,fertilization and fruit set in mango: A scanning electron microscopy study

Mango malformation is the most threaten disease that limits mango production, worldwide. For a long time, due to its complex nature, the cause and causal agents were strongly disputed. Diverse Fusaria, including Fusarium mangiferae, are known to be associated with the disease. There are indications that augmented level of endogenous ethylene in response to various abiotic and biotic stresses alters the morphology of reproductive organs. Here, scanning electron microscopy (SEM) of healthy and malformed reproductive organs of mango cv. Baramasi was performed to compare the functional morphology. The SEM study revealed that anthers of hermaphrodite healthy flowers were bilobed with large number of turgid pollen grains whereas malformed flowers showed fused lobed anthers with scanty deformed pollen grains. Furthermore, the stigma of healthy flowers exhibited a broad landing pad as compared to malformed stigma which showed hooked and pointed tip. All these impaired morphology of male and female reproductive organs lead to failure of sexual reproduction. This is the first evidence to show fused lobed anther with impaired pollen grains and hooked stigma with poor stigmatic receptivity are mainly responsible for restricting the pollen germination and pollen tube growth. Here we suggest that abnormal development of anthers and pistils is due to endogenously produced stress ethylene. Further, added load of cyanide, a byproduct of ethylene biosynthesis, may also contribute to the development of necrosis which lead to desiccation of anther and pistil during hypersensitive response of plants.     

Comparative morphological analysis of peripheral endocrine glands in small mammals inhabiting areas with high levels of radioactive pollutants and exposed to chronic irradiation in laboratory experiments

The comparative study of cellular-tissue reactions in endocrine organs (thyroid and suprarenal glands, ovary) of rodents exposed to radiation in natural conditions (Radium station in Komi Republic and 30-km zone of Chernobyl APP) and experimental conditions modeling the chronic exposure has been conducted. There is evidence that chronic irradiation in low doses causes morphological disorders in different levels of structural organization (cellular-tissue, organism and population levels). The experimental results showed that observed variations in thyroid, suprarenal glands and ovary by morphometric parameters reflect the natural changes in their functional activity (within the physiological limits). These changes are directed at the homeostasis maintenance in changed conditions and have a compensatory and adaptation character. The effects of low dose radiation influence with combination of other agents may be amplified at the cellular-tissue reactions level. In comparison with experimental results, the natural conditions (high level of radioactivity with alpha- and beta-emitters, high natural radionuclides, toxic elements and extreme climatic factors) induce more expressed changes as a significant increasing of chromosomal and genes mutations in cells, destructive processes in organs of endocrine system and disorders of reproductive functions.     

Comparative morphological analysis of peripheral endocrine glands of small mammals inhabiting areas with high levels of radioactivity and exposed to chronic irradiation in model experiments

Comparative study of cellular-tissue reactions in the endocrine organs (thyroid and adrenal glands and ovary) of rodents exposed to radiation under natural conditions (Radium station in the Komi Republic and 30-km zone of Chernobyl NPP) and under experimental conditions modeling chronic exposure is carried out. Evidence is found that low-dose chronic irradiation causes morphological disorders at different levels of structural organization (cellular-tissue, organism, and population levels). The experimental results show that the observed variations in the morphometric parameters of the thyroid and adrenal glands and ovary reflect natural changes in their functional activity (within the physiological limits). These changes are directed at the maintenance of homeostasis under altered conditions and have a compensatory and adaptive character. The effects of low-dose radiation in combination with other agents may be amplified at the level of cellular-tissue reactions. In comparison with the experimental results, natural conditions (high level of radioactivity due to α and β emitters, high natural radionuclides, toxic elements, and extreme climatic factors) induce more pronounced changes, including a significant increase in chromosomal and gene mutations in cells, destructive processes in the organs of the endocrine system, and disorders of reproductive functions.

     

植物源活性物质对昆虫生殖的干扰作用

昆虫的繁盛与其强大的生殖能力密切相关,而环境友好的植物源活性物质是可持续的害虫防治方法之一,能够通过多种作用机制影响昆虫的生殖发育。本文从昆虫生殖行为、生长发育、生殖细胞或器官、生殖地位与性比、共生微生物等方面,综述了植物源活性物质对昆虫生殖干扰机理的研究进展及相关的应用情况,以期为昆虫生殖发育干扰的进一步研究与害虫综合防控技术的研发提供参考。     

Performing Vaginal Lavage,Crystal Violet Staining,and Vaginal Cytological Evaluation for Mouse Estrous Cycle Staging Identification

A rapid means of assessing reproductive status in rodents is useful not only in the study of reproductive dysfunction but is also required for the production of new mouse models of disease and investigations into the hormonal regulation of tissue degeneration (or regeneration) following pathological challenge. The murine reproductive (or estrous) cycle is divided into 4 stages: proestrus, estrus, metestrus, and diestrus. Defined fluctuations in circulating levels of the ovarian steroids 17-β-estradiol and progesterone, the gonadotropins luteinizing and follicle stimulating hormones, and the luteotropic hormone prolactin signal transition through these reproductive stages. Changes in cell typology within the murine vaginal canal reflect these underlying endocrine events. Daily assessment of the relative ratio of nucleated epithelial cells, cornified squamous epithelial cells, and leukocytes present in vaginal smears can be used to identify murine estrous stages. The degree of invasiveness, however, employed in collecting these samples can alter reproductive status and elicit an inflammatory response that can confound cytological assessment of smears. Here, we describe a simple, non-invasive protocol that can be used to determine the stage of the estrous cycle of a female mouse without altering her reproductive cycle. We detail how to differentiate between the four stages of the estrous cycle by collection and analysis of predominant cell typology in vaginal smears and we show how these changes can be interpreted with respect to endocrine status.     

Steroidogenic factor 1 (SF-1) is essential for endocrine development and functionProceedings of Xth International Congress on Hormonal Steroids, Quebec, Canada, 17–21 June 1998.

Steroidogenic factor 1 (SF-1), an orphan nuclear receptor, initially was isolated as a key regulator of the tissue-specific expression of the cytochrome P450 steroid hydroxylases. Thereafter, analyses of sites of SF-1 expression during mouse embryological development hinted at considerably expanded roles for SF-1, roles that were strikingly confirmed through the analyses of SF-1 knockout mice. These SF-1 knockout mice exhibited adrenal and gonadal agenesis, associated with male-to-female sex reversal of their internal and external genitalia and death from adrenocortical insufficiency. These findings showed unequivocally that SF-1 is essential for the embryonic survival of the primary steroidogenic organs. SF-1 knockout mice also had impaired pituitary expression of gonadotropins and agenesis of the ventromedial hypothalamic nucleus (VMH), establishing that SF-1 regulates reproductive function at all three levels of the hypothalamic–pituitary–gonadal axis. This article reviews the experiments that have defined these essential roles of SF-1 in endocrine development and highlights important areas for future studies.     

Effects of 17β-estradiol and bisphenol A on the formation of reproductive organs in planarians

Planarians have a remarkable capacity for regeneration after ablation, and they reproduce asexually by fission. However, some planarians can also reproduce and maintain their sexual organs. During the regenerative process, their existing sexual organs degenerate and new ones develop. However, little is known about hormonal regulation during the development of reproductive organs in planarians. In this study, we investigated the effects of 17β-estradiol (a steroid) and bisphenol A (an endocrine disrupter) on the formation of sexual organs in the hermaphroditic planarian Dugesia ryukyuensis. Under control conditions, all worm tissues regenerated into sexual planarians with sexual organs within 4 weeks after ablation. However, in the presence of bisphenol A or 17β-estradiol, although they apparently regenerated into sexual planarians, the yolk glands, which are one of the female sexual organs, failed to regenerate even 7 weeks after ablation. These data suggest that planarians have a steroid hormone system, which plays a key role in the formation and maturation of sexual organs.     

Influences of weather on reproductive function in male Song sparrows, Melospiza melodia

The avian reproductive cycle is integrated and timed by a variety of environmental factors that include day length, availability of food, nest sites, presence of a mate, etc. However, reproduction can be delayed or disrupted by inclement weather and, until recently, the endocrine responses of avian species to storms were entirely unknown. This communication describes changes in endocrine state in free-living male Song sparrows, Melospiza melodia, during gonadal recrudescence after a severe winter, and in response to storms in early spring and summer. Both the severe winter weather and an early spring snow storm delayed testicular development, and depressed circulating levels of testosterone. The sparrows did not appear to be stressed, however, since body mass and fat deposits were higher than in birds sampled during the previous spring after a less severe winter.
A second storm occurred in late May and early June when Song sparrows were feeding young. Curiously, plasma levels of testosterone were not affected, but the sparrows did appear to be stressed since there was a significant decline in body mass, and a marked increase in circulating levels of corticosterone. These data suggest that the effects of inclement weather on reproductive function can vary in relation to the stage in the reproductive cycle when the storm strikes, and that the endocrine mechanisms underlying acclimatization to severe meteorological conditions are also different.     

Neuromedin B and Its Receptor: Gene Cloning,Tissue Distribution and Expression Levels of the Reproductive Axis in Pigs

Neuromedin B is one member of a family of bombesin-like peptides, which performs a variety of physiological functions via their receptor (NMBR) in most mammals. However, the genes encoding NMB and NMBR and their functions especially reproduction of the pigs are currently not fully understood. To research the physiological functions of NMB, we cloned and analyzed the NMB and NMBR genes, and systematically investigated the expression levels of NMB and NMBR mRNA using relative real-time PCR and the distribution of NMBR by immunohistochemistry (IHC). Experimental results show that the sequences of the amino acid and gene of NMB and NMBR were highly conservative and homology in many species, Significantly, the relative RT-PCR results revealed that NMB was mainly expressed in the central nervous system (CNS), whereas NMBR is highly expressed in peripheral tissues and organs, such as endocrine tissues, glands and reproductive organs. The IHC results show that NMBR positive cells were widely distributed in the body, such as respiratory and circulatory system, digestive system, urogenital system, in lymphatic organs and in the endocrine system. We also systematically investigated expression levels of NMB and NMBR in the reproductive axis using relative real-time PCR. In sow estrous cycle, the hypothalamic levels of both NMB and NMBR mRAN were similar, but the expression levels of the pituitary were negatively correlated. Expression levels in the ovarian system are lowest in metestrus phases and highest in proestrus and estrus phases. In boar post-natal development stages, the hypothalamic, pituitary and testicular levels of NMB and NMBR mRNAs showed developmental changes on postnatal day 30, 60, 90 and 120. Taken together, this study provided molecular and morphological data necessary for further research of physiological function of NMB/NMBR system in the pigs.     

A treatise on hazards of endocrine disruptors and tool to evaluate them

Hormones mediate a major part of our essential physiological functions. Both endogenous and exogenous compounds and their metabolites are known to act through hormone receptors leading to regulation of endocrine function. The endogenous ligands that control reproductive functions are generally steroids such as 17beta-estradiol, androgens, progesterone, pregnenolone and glucocorticoids. However, exogenous compounds that are structurally and functionally similar gain entry into animals including humans through the diet or by occupational exposures, causing endocrine disruption. In the recent decade, there is a lot of apprehension about the so-called "endocrine disruptors" which are wide spread in the environment, mainly due to unrestricted human activity. These compounds of anthropogenic or natural origin mimic the action of sex hormones and can interfere with the endocrine system. It has been hypothesized that environmental exposure to synthetic estrogenic chemicals and related endocrine active compounds may be responsible for malformations in the male reproductive tract, crytorchidism, hypospadias, decrease in sperm counts, decreased male reproductive capacity and even testicular cancers. The increasing concern in both public and scientific communities about these abnormalities have prompted the initiation of epidemiological studies to not only identify, but to also analyze the short and long term effects of endocrine disruptors. As a result, a number of assays have been developed and are undergoing validation aimed at high throughput screening of chemical agents that disrupt endocrine activity. This review consolidates the findings of epidemiological studies, particularly in relation to male reproductive disorders and brings to light the various types of in vitro and in vivo models that are available for tiered testing of suspected compounds.     

Clasper gland morphology and development in Potamotrygon magdalenae (Elasmobranchii: Potamotrygonidae)

Clasper gland morphology and development in Potamotrygon magdalenae and its relation with the acquisition of reproductive maturity is described in males of different developmental stages (embryos, neonates, juveniles, and reproductively active and resting adults). The glands are subcutaneous masses in the proximal base of each clasper. They are partially bilobate organs with a ventral groove that bears a row of papillae. Glands tend to be asymmetric, the left gland has a larger size, a trend that has been observed in other organs of elasmobranchs. Glands are formed by radially organized tubular secretory units lined with a simple columnar epithelium with basal nuclei and granular eosinophilic cytoplasm; vascularized loose connective tissue surrounds the gland units. The gland is covered by two layers of striated muscle tissue in circular and longitudinal arrangement. The clasper glands begin to develop in neonates and their secretory activity begins in juveniles. The active secretion of the clasper gland is observed in mature males, it includes glycoproteins and sulfated mucopolysaccharides. The size of the glands has a positive and direct relationship with body size, measured as disc width. Significant differences in clasper gland size were found between mature (active and resting) and immature (neonates and juveniles) males, suggesting that the acquisition of the sexual maturity involves the increase in the size of the gland due to a highly augmented secretory activity. Therefore, clasper glands are clearly associated with the reproductive activity of males and their secretion should have an endocrine control as other sexual secondary organs. J. Morphol. 278:369–379, 2017. © 2017 Wiley Periodicals, Inc.     

Inflammatory repercussions in female steroid responsive glands after perinatal exposure to bisphenol A and 17-β estradiol

The mammary gland (MG) and female prostate are plastic reproductive organs which are highly responsive to hormones. Thus, endocrine disruptors, such as bisphenol A (BPA) and exogenous estrogens, negatively affect glandular homeostasis. In addition to previously described alterations, changes in inflammatory markers expression also trigger the development of a microenvironment that contributes to tumor progression. The current work aimed to evaluate the inflammatory responses of the MG and prostate gland to BPA (50 µg/kg) and 17-β estradiol (35 µg/kg) exposure during the perinatal window of susceptibility. The results showed that at 6 months of age there was an increase in the number of phospho-STAT3 (P-STAT3) positive cells in the female prostate from animals perinatally exposed to 50 µg/kg BPA daily. In addition, the number of macrophages increased in these animals in comparison with nonexposed animals, as shown by the F4/80 marker. Despite an increase in the incidence of lobuloalveolar and intraductal hyperplasia, the MG did not show any difference in the expression of the four inflammatory markers evaluated: tumor necrosis factor-α, COX-2, P-STAT3, and F4/80. Analysis of both glands from the same animal led to the conclusion that exposure to endocrine disruptors during the perinatal window of susceptibility leads to different inflammatory responses in different reproductive organs. As the prostate is more susceptible to these inflammatory mechanisms, it is reasonable to affirm that possible neoplastic alterations in this organ are related to changes in the inflammatory pattern of the stroma, a characteristic that is not evident in the MG.     

"Natural" progesterone: information on fetal effects

BACKGROUND: A variety of progestational agents have been used therapeutically and evaluated for adverse effects over the last 50 years. However, progesterone itself has come into use as a therapeutic agent only recently with the development of an orally bioavailable "micronized" preparation. METHODS: The current review examines progesterone adverse effects as identified in the larger literature on the toxicity of progestational agents and pharmacokinetics. RESULTS: Progesterone has cytoplasmic and membrane receptors in a variety of reproductive and nonreproductive tissues including the brain and is a potent inhibitor of GnRH. Limited information is available on progesterone receptors and actions in the fetus. Concern about exogenous progestagen effects on fetal reproductive tract development have led to considerable human research over the years, but this literature review demonstrates that contemporary developmental toxicology research on progesterone is lacking. CONCLUSIONS: Progesterone is a potent, multi-faceted endocrine agent with an expanding therapeutic profile and a minimal scientific database for evaluating safe use during pregnancy.     

Kisspeptin在女性生殖内分泌和辅助生殖技术中的研究进展

近年来研究显示,kisspeptin在大脑的性别分化、性激素正负反馈调节、青春期始动以及机体能量信号转导等生理过程中起到重要作用,表明kisspeptin可能是女性生殖功能成熟及调控的一个关键性信号因子。除下丘脑分泌的kisspeptin之外,生殖器官局部表达的kisspeptin在机体正常生殖过程中的作用也不断得到证实。研究表明,很多生殖内分泌疾病,如单纯性促性腺激素分泌不足的性腺机能减退症(isolated hypogonadotropic hypogonadism, IHH)、多囊卵巢综合征(polycystic ovary syndrome, PCOS)、卵巢早衰(premature ovarian failure, POF)、病理性高泌乳素血症等,都与kisspeptin的异常表达有关。通过给予外源性kisspeptin可解决辅助生殖技术应用中的一些问题。本文主要就kisspeptin在女性生殖内分泌尤其是在辅助生殖领域研究中所取得的进展进行论述。     

Lindane may modulate the female reproductive development through the interaction with ER-beta: an in vivo-in vitro approach

Lindane (gamma-HCH) is a persistent environmental pollutant that may act as endocrine disrupter, affecting the nervous, immune and reproductive system, possibly through endocrine-mediated mechanisms. Since both estrogen receptors (ER-alpha and -beta) have shown to be target for endocrine disruption, we investigated the role of gamma-HCH on the development of female reproductive system. For an in vivo evaluation of gamma-HCH effects during prenatal period, pregnant CD1 mice were treated p.o. on gestational days 9-16 with 15 mg/kg bw/day of gamma-HCH and vehicle. The in vivo findings in treated F1 pups - in the absence of signs of systemic toxicity - included increase in the absolute and relative and absolute uterus weight revealed on post-natal day 22, earlier vaginal patency and reduced diameters of primary oocytes at fully sexual maturity. No effects on steroid hormone metabolism (aromatase, testosterone catabolism) were observed. Thus, gamma-HCH elicited subtle effects on female reproductive development likely mediated by ER-beta-mediated pathway(s), without a concurrent impairment of steroid hormone metabolism. Furthermore, to verify whether the endocrine interference of gamma-HCH is attributable to stimulation of ER-beta-mediated pathway(s), its effect has been evaluated in vitro on a cell line, LNCaP, expressing only functional ER-beta. In vitro treatments revealed a concentration-related effect on LNCaP cell viability and proliferation. Significantly, the contemporary addition of a pure anti-estrogen, the ER antagonist ICI 182,780, completely reversed gamma-HCH effects indicating an ER-beta-mediated action. Our findings indicate that gamma-HCH may act as endocrine disruptor during the female reproductive system development and ER-beta as a potential target for this compound and other endocrine disrupting chemicals as well.     

Neuroendocrine and behavioral implications of endocrine disrupting chemicals in quail

Studies in our laboratory have focused on endocrine, neuroendocrine, and behavioral components of reproduction in the Japanese quail. These studies considered various stages in the life cycle, including embryonic development, sexual maturation, adult reproductive function, and aging. A major focus of our research has been the role of neuroendocrine systems that appear to synchronize both endocrine and behavioral responses. These studies provide the basis for our more recent research on the impact of endocrine disrupting chemicals (EDCs) on reproductive function in the Japanese quail. These endocrine active chemicals include pesticides, herbicides, industrial products, and plant phytoestrogens. Many of these chemicals appear to mimic vertebrate steroids, often by interacting with steroid receptors. However, most EDCs have relatively weak biological activity compared to native steroid hormones. Therefore, it becomes important to understand the mode and mechanism of action of classes of these chemicals and sensitive stages in the life history of various species. Precocial birds, such as the Japanese quail, are likely to be sensitive to EDC effects during embryonic development, because sexual differentiation occurs during this period. Accordingly, adult quail may be less impacted by EDC exposure. Because there are a great many data available on normal development and reproductive function in this species, the Japanese quail provides an excellent model for examining the effects of EDCs. Thus, we have begun studies using a Japanese quail model system to study the effects of EDCs on reproductive endocrine and behavioral responses. In this review, we have two goals: first, to provide a summary of reproductive development and sexual differentiation in intact Japanese quail embryos, including ontogenetic patterns in steroid hormones in the embryonic and maturing quail. Second, we discuss some recent data from experiments in our laboratory in which EDCs have been tested in Japanese quail. The Japanese quail provides an excellent avian model for testing EDCs because this species has well-characterized reproductive endocrine and behavioral responses. Considerable research has been conducted in quail in which the effects of embryonic steroid exposure have been studied relative to reproductive behavior. Moreover, developmental processes have been studied extensively and include investigations of the reproductive axis, thyroid system, and stress and immune responses. We have conducted a number of studies, which have considered long-term neuroendocrine consequences as well as behavioral responses to steroids. Some of these studies have specifically tested the effects of embryonic steroid exposure on later reproductive function in a multigenerational context. A multigenerational exposure provides a basis for understanding potential exposure scenarios in the field. In addition, potential routes of exposure to EDCs for avian species are being considered, as well as differential effects due to stage of the life cycle at exposure to an EDC. The studies in our laboratory have used both diet and egg injection as modes of exposure for Japanese quail. In this way, birds were exposed to a specific dose of an EDC at a selected stage in development by injection. Alternatively, dietary exposure appears to be a primary route of exposure; therefore experimental exposure through the diet mimics potential field situations. Thus, experiments should consider a number of aspects of exposure when attempting to replicate field exposures to EDCs.