High resolution effect-directed analysis of steroid hormone (ant)agonists in surface and wastewater quality monitoring.

Monitoring of chemical water quality is extremely challenging due to the large variety of compounds and the presence of biologically active compounds with unknown chemical identity. Previously, we developed a high resolution Effect-Directed Analysis (EDA) platform that combines liquid chromatography with high resolution mass spectrometry and parallel bioassay detection. In this study, the platform is combined with CALUX bioassays for (anti)androgenic, estrogenic and glucocorticoid activities, and the performance of the platform is evaluated. It appeared to render very repeatable results, with high recoveries of spiked compounds and high consistency between the mass spectrometric and bioassay results. Application of the platform to wastewater treatment plant effluent and surface water samples led to the identification of several compounds contributing to the measured activities. Eventually, a workflow is proposed for the application of the platform in a routine monitoring context. The workflow divides the platform into four phases, of which one to all can be performed depending on the research question and the results obtained. This allows one to make a balance between the effort put into the platform and the certainty and depth by which active compounds will be identified. The EDA platform is a valuable tool to identify unknown bioactive compounds, both in an academic setting as in the context of legislative, governmental or routine monitoring.

Regulation of astroglia by gonadal steroid hormones under physiological and pathological conditions.

In the last years there has been a considerable advance in the knowledge on the regulation of astrocytes by sex steroids under physiological and pathological conditions. By the activation of a variety of nuclear and membrane receptors, sex steroid hormones regulate the functions of astrocytes and their communication with other cell types in the central nervous system. Under physiological conditions astrocytes participate in the neuroendocrine and behavioral actions of gonadal steroids, as well as in the hormonal control of brain tissue homeostasis. Under pathological conditions astrocytes mediate, at least partially, the neuroprotective effects of gonadal steroid hormones; given that sex steroids modulate reactive astrogliosis and reduce the release of pro-inflammatory molecules by these cells. Given the side effects that sex steroids may have when administered systemically, a number of synthetic agonists of the receptors for gonadal steroid hormones in the nervous system have been developed, and may be considered for clinical use after brain injury as potential enhancers of the neuroprotective astrocytic functions.

Evolutionary Changes in Sensitivity to Hormonally Induced Gonadal Sex Reversal in a Frog Species.

The Japanese frog Glandirana rugosa is unique in that it shows geographic variation in sex chromosome differentiation and heterogametic sex determination. To elucidate the cause of interpopulation differences in gonadal sex differentiation, we investigated hormonally induced sex reversal and the expression patterns of genes associated with sex determination during early tadpole development. We found that sex reversal was easily induced in XX females and XY males of 2 forms (West-Japan and East-Japan) of G. rugosa with the ancestral homomorphic sex chromosomes under male heterogametic sex determination. During sex reversal, expression of CYP19 and/or FOXL2 was dependent on the phenotypic sex of the gonad. In contrast, sex reversal was not induced in ZW females of a population with a heteromorphic ZW sex chromosome system or in XX females or XY males in a population with a heteromorphic XY sex chromosome system. The latter 2 populations are evolutionarily derived forms. These results indicate an evolutionary direction for the gonadal sex differentiation mechanism. The original system was highly sensitive to sex hormones and allowed almost complete sex reversal. From this ancestral form, a new system evolved that was resistant to hormones and showed a change in the heterogametic sex and the sex chromosome differentiation mechanism.

Therapeutic Neuroendocrine Agonist and Antagonist Analogs of Hypothalamic Neuropeptides as Modulators of the Hypothalamic-Pituitary-Gonadal Axis.

Reproductive hormones play a role at all stages of life and affect most tissues of the body. Gonadotropin-releasing hormone (GnRH) synthesized in the hypothalamus stimulates the secretion of gonadotropins which in turn stimulate gonadal sex hormone production and gamete formation. This hypothalamic-pituitary-gonadal (HPG) axis has, therefore, been the target for the development of numerous drugs which regulate it at various points. These include sex steroid agonists and antagonists, inhibitors of sex steroid biosynthesis, and GnRH agonists and antagonists, which have found extensive applications in treating numerous conditions such as precocious puberty, delayed puberty, prostate cancer, benign prostatic hyperplasia, endometriosis, uterine fibroids and also in in vitro fertilization protocols. The novel neuroendocrine peptides, kisspeptin (KP) and neurokinin B (NKB), were recently discovered as upstream regulators of GnRH, and inactivating mutations of KP and NKB ligands or receptors result in a failure to progress through puberty. Agonists and antagonists of KP and NKB are being developed as more subtle modulators of the HPG axis. These new drugs offer additional and alternative therapeutic options in pediatric and adult hormone-dependent diseases.

Cistanche tubulosa ethanol extract mediates rat sex hormone levels by induction of testicular steroidgenic enzymes.

CONTEXT: Plants of the genus Cistanche Hoffmg. et Link (Orobanchaceae) are usually used as ethno-medicine in Eastern Asia. Pharmacology studies have shown that Cistanche possesses an androgen-like effect; however, the exact mechanism is unclear. OBJECTIVE: The present study determines the effect of ethanol extract of Cistanche tubulosa (Schenk) R. Wight stem (CTE) on hormone levels and testicular steroidogenic enzymes in rats. MATERIALS AND METHODS: Phenylethanoid glycoside content of CTE was detected by UV spectrophotometry. Rats were fed with different doses of CTE (0.2, 0.4, and 0.8 g/kg) by intragastric administration for 20 d. Sperm parameters were measured by staining and counting method. The level of progesterone and testosterone in serum was quantified by radioimmunoassay. The expression levels of cholesterol side-chain cleavage enzyme (CYP11A1), 17α-hydroxylase/17, 20-lyase (CYP17A1), and a liver metabolic enzyme (CYP3A4) in the microsome were assessed by immunohistochemical staining or/and western blot analysis. RESULTS: The study illustrates that the administration of CTE (0.4 and 0.8 g/kg) increased sperm count (2.3- and 2.7-folds) and sperm motility (1.3- and 1.4-folds) and decreased the abnormal sperm (0.76- and 0.6-folds). The serum level of progesterone and testosterone in rats was also increased by CTE administration (p < 0.05). Results of immunohistochemistry and western blot analysis confirmed that the expression of CYP11A1, CYP17A1, and CYP3A4 was enhanced by CTE (p < 0.05). It was also found that high-dose of CTE can cause mild hepatic edema. CONCLUSION: Our results suggest that the increase in sex hormone levels could be mediated by the induction of testicular steroidogenic enzymes.

Effect of growth promotants on the occurrence of endogenous and synthetic steroid hormones on feedlot soils and in runoff from beef cattle feeding operations.

Supplements and growth promotants containing steroid hormones are routinely administered to beef cattle to improve feeding efficiency, reduce behavioral problems, and enhance production. As a result, beef cattle manure will contain both synthetic steroids as well as a range of endogenous steroids including androgens, estrogens, and progestogens. A two-year controlled study was conducted in which beef cattle were administered steroid hormones via subcutaneous implants and feed additives and the occurrence of 16 endogenous and synthetic steroid hormones and metabolites was evaluated in runoff from beef cattle feedlots and in manure and soil collected from feedlot surfaces. Samples were extracted and analyzed using liquid chromatography tandem mass spectrometryfor metabolites of the synthetic androgen trenbolone acetate, 17α-trenbolone, 17ß-trenbolone, for the nonsteroidal semisynthetic estrogen agonist, α-zearalanol, and the synthetic progesterone melengesterol acetate, as well as a wide range of endogeneous estrogens, androgens, and fusarium metabolites. Synthetic steroids including trenbolone metabolites and melengestrol acetate were detected in fresh manure and in feedlot surface soils from cattle administered synthetic steroids at concentrations up to 55 ± 22 ng/g dry weight (dw) (17α-trenbolone) and 6.5 ± 0.4 ng/g dw (melengesterol acetate). Melengesterol acetate was detected in 6% of runoff samples from feedlots holding cattle administered synthetic steroids at concentrations ranging up to 115 ng/L. The presence of melengesterol acetate in runoff from beef cattle feeding operations has not been previously reported. Synthetic steroids were not detected in manure or runoff from control cattle. A wide range of endogenous hormones were detected in runoff and feedlot surface soils and manure from cattle given synthetic steroids and from control cattle, with no statistically significant differences in concentration. These results indicate that runoff from confined animal production facilities is of environmental and public health concern regardless of the use of growth promotants.

Endocrine disruptors as a threat to neurological function.

Endocrine disruption is a concept and principle whose origins can be traced to the beginnings of the environmental movement in the 1960s. It began with puzzlement about and the flaring of research on the decline of wildlife, particularly avian species. The proposed causes accented pesticides, especially persistent organochlorines such as DDT. Its scope gradually widened beyond pesticides, and, as endocrine disruption offered an explanation for the wildlife phenomena, it seemed to explain, as well, changes in fertility and disorders of male reproduction such as testicular cancer. Once disturbed gonadal hormone function became the most likely explanation, it provoked other questions. The most challenging arose because of how critical gonadal hormones are to brain function, especially as determinants of brain sexual differentiation. Pursuit of such connections has generated a robust literature embracing a broad swath of chemical classes. How endocrine disrupting chemicals influence the adult and aging brain is a question, so far mostly ignored because of the emphasis on early development, that warrants vigorous investigation. Gonadal hormones are crucial to optimal brain function during maturity and even senescence. They are pivotal to the processes of neurogenesis. They exert protective actions against neurodegenerative disorders such as dementia and support smoothly functioning cognitive activities. The limited research conducted so far on endocrine disruptors, aging, and neurogenesis argues that they should be overlooked no longer.

Molecular biomarkers of endocrine disruption in small model fish.

A wide range of environmental contaminants can interfere with hormonal regulation in vertebrates. These endocrine disrupting chemicals (EDCs) are of high relevance for human and wildlife health, since endocrine signalling controls many essential physiological processes which impact on the individual's health, such as growth and development, stress response, and ultimately reproduction and population development. Small fish represent a cost-effective model for testing potential EDCs allowing the possibility to integrate from molecular to phenotypic and functional effects. We have comprehensively reviewed exposure-effect data from four different small model fish: zebrafish, medaka, fathead minnow, and the three-spined stickleback. The majority of available data refer to EDCs interfering with reproductive hormones. However, we have also included interactions with other hormone systems, particularly the thyroid hormones. We demonstrate that the available data clearly indicates the predictive potential of molecular biomarkers, supporting the development and regulatory application of simple molecular-based screening assays using small model fish for EDC testing.

Valproate is an anti-androgen and anti-progestin.

Anti-convulsant treatment is associated with a high prevalence of reproductive dysfunction compared with age-matched non-epileptics. We examined the widely used anti-convulsants valproate (VPA) and carbamazepine (CBZ) for steroidal bioactivity using a yeast-based steroid receptor-beta-galactosidase reporter assay for the androgen receptor (AR), progesterone receptor (PR) or estrogen receptor (ER). Bioassays were performed (a) to detect agonist activity by exposing yeast to 100 microM CBZ or VPA or (b) to detect antagonist activity by exposing yeast stimulated with testosterone (5 x 10(-9) M, AR), progesterone (1.6 x 10(-9) M, PR) or estradiol (2.6 x 10(-11) M, ER) together with either VPA or CBZ for 4 (PR) or 16 (AR, ER) hours. VPA showed dose-dependent (1-800 microM) inhibition of progesterone-induced PR- and testosterone-induced AR activity but had no ER antagonist bioactivity and no significant PR, AR or ER agonist bioactivity. VPA also showed a dose-dependent (1-200 microM) blockade of DHT's suppression of AR-mediated NF-kappaB activation in human mammalian cells. By contrast, CBZ had no significant PR, AR or ER agonist or AR and ER antagonist bioactivity but at the highest concentration tested (800 microM) it did antagonize PR activity. We conclude that VPA is a non-steroidal antagonist for human AR and PR but not ER. VPA's androgen and progesterone antagonism at concentrations within therapeutic blood levels (350-700 microM) seems likely to contribute to the frequency of reproductive endocrine disturbances among patients treated with VPA.

[Perspectives on endocrine disruption]. / Perspectivas en disrupción endocrina.

Two decades ago, reports of alterations in the reproductive function of some wild animal species and clear evidence of human and animal exposure to chemical substances with hormonal activity agonist and antagonist generated what is known now as the hypothesis of endocrine disruption. This is an emerging environmental health problem that has challenged some of the paradigms on which the control and regulation of the use of chemical compounds is based. The need to include in routine toxicology tests new research objectives that specifically refer to the development and growth of species and to the homeostasis and functionality of hormonal systems, has served to complicate both the evaluation of new compounds and the re-evaluation of existing ones. The repercussions on regulation and international trade have not taken long to be felt. On both sides of the Atlantic, screening systems for endocrine disrupters have been designed and established, and research programmes have been launched to characterise and quantify adverse effects on human and animal health and to develop preventive measures.

Endocrine active compounds: from biology to dose response assessment.

Endocrine active compounds (EACs) alter signaling processes responsible for regulation and coordination of physiological functions during development and adulthood. The potential that adverse effects of these compounds have gone unrecognized has focused attention on their toxicology. The primary response to this concern has been development of additional hazard identification methods. This review discusses issues for dose response (DR) analyses for EACs, including definitions of adversity, implications of alternative modes of action, the roles homeostatic and developmental regulatory feedback processes play in creating DR behaviors, uses of in vitro data in DR analyses, and induction of effects by natural and synthetic compounds in the context of endogenous hormone background. Current risk assessment guidance applicable to endocrine-mediated effects provide limited default methods for evaluating DR behaviors and making interspecies comparisons. Improved DR methods for EACs will be achieved through the use of mode of action and dosimetry data to better characterize potential human risks.

Vulnerability of the endocrine system to xenobiotic influence.

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

Development of a Tier I screening battery for detecting endocrine-active compounds (EACs).

One of the components of our research program is development of a mode-of-action screening battery to detect several different types of endocrine-active compounds (EACs). Our working hypothesis is that a comprehensive short-term in vivo/in vitro battery can be developed to identify endocrine toxicants using a collection of endpoints. The goals of this battery are that it be quick, cost effective, and predictive. The purpose of this battery is to identify potential EACs and to assess their potency in order to prioritize compounds for further study. Two in vivo screens (intact male and ovariectomized female rats) are being evaluated for their ability to detect several different types of endocrine activity. To validate this screen, 15 compounds with known endocrine activities are being used to evaluate a collection of different endpoints for their variability, stability over time, predictiveness, and dose dependency. These positive controls were chosen because they can modulate development, reproduction, or cancer. The advantage of an in vivo screen is that it utilizes a metabolically and physiologically intact system. The male in vivo battery will be used to assess several different types of endocrine activity, primarily by using a comprehensive hormonal battery. The female in vivo battery will be used to identify compounds which are either estrogenic/antiestrogenic or can alter the prolactin pathway. The in vitro portion of the screening battery consists of a yeast transactivation system (YTS). The YTS is being evaluated for its ability to identify compounds which are agonists or antagonists to the estrogen, androgen, or progesterone receptors. The expression of mammalian receptors in yeast allows for assessment of steroid-dependent transcriptional activators. The value of this system is that it can be used as a routine screen for compounds that interact with steroid receptors. Alterations in ligand binding to these receptors can be correlated with alterations in development via masculinization of females and/or feminization of males, decreases in reproductive success, or modulation of cancer incidence from in vivo tests. The in vivo and in vitro screens are designed to be run in parallel with built-in redundancy in order to reduce the probability of false-negative/ positive responses.