Phytoestrogens: adverse effects on reproduction in California quail

Optimizing pre-treatment of alkaline hydrolysis RP-HPLC for enhancing accuracy of soy isoflavone determination

Isoflavones (IFs) are important bioactive compounds which offers several benefits to human health. Despite the importance of IFs content, there are still some deficiencies in the existing methods. The objective of this study is to optimize key parameters of alkaline hydrolysis method for enhancing both reliability and accuracy of quantitative analysis of IFs contents in soybeans and soy protein products. Solvent type, extraction temperature, heating mode, alkaline concentration, hydrolysis temperature, hydrolysis time and some details are key points to target analytes which yield determining parameters. The biggest IFs content was obtained by extraction using methanol (MeOH)/water (80:20, v/v) in a 75 ℃ oven for 2 h, and hydrolyzation with 3 M NaOH solution at a room temperature for 10 mins. The total IFs content obtained by the improved method has increased by 16.4% compared with AOAC Official Method 2001.10. The accuracy of the method was evaluated using the relative standard deviation (RSD). Intraday accuracies in the total amount of isoflavones of four samples were 0.03%-0.63% (n = 3). Interday accuracy in the total amount of isoflavones was 2.71% (n = 6). LOD of IFs ranged from 0.1μg/mL for aglycones to 0.2μg/mL for glucosides. LOQ of IFs ranged from 0.3μg/mL for aglycones to 0.5μg/mL for glucosides. The improved method was proven to be a more accurate way to determine IFs contents in soybeans and soy protein products and thus making it useful for quality control and systematic in-depth study of soybeans and soy products; even to further assess the dietary soy exposure and the soy-health association.

Environmental disruption of reproductive rhythms

Reproduction is a key biological function requiring a precise synchronization with annual and daily cues to cope with environmental fluctuations. Therefore, humans and animals have developed well-conserved photoneuroendocrine pathways to integrate and process daily and seasonal light signals within the hypothalamic-pituitary-gonadal axis. However, in the past century, industrialization and the modern 24/7 human lifestyle have imposed detrimental changes in natural habitats and rhythms of life. Indeed, exposure to an excessive amount of artificial light at inappropriate timing because of shift work and nocturnal urban lighting, as well as the ubiquitous environmental contamination by endocrine-disrupting chemicals, threaten the integrity of the daily and seasonal timing of biological functions. Here, we review recent epidemiological, field and experimental studies to discuss how light and chemical pollution of the environment can disrupt reproductive rhythms by interfering with the photoneuroendocrine timing system.

Multiomics analysis of soybean meal induced marine fish enteritis in juvenile pearl gentian grouper, Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂

As an important protein source, soybean products can cause intestinal inflammation and injury in many animals including human beings, particularly infants and juvenile individuals. Research in this field has been performed for terrestrial animals and fish, but still lacks integrity and systematicness. In this study, the main biological processes in the intestinal tract of marine fish juvenile pearl gentian grouper in the state of soybean meal-induced enteritis (SBMIE) were analyzed. A total of 720 groupers with an approximate initial weight of 12.5 g were randomly divided into three groups: the fish meal (FM) control group, the 20% SBM group (SBM20), and the SBM40 group (n = 4). Three iso-nitrogenous and iso-lipidic diets were prepared and fed to fish for 10 weeks. Each barrel contained a water volume of about 1 m3 in and was exposed to natural light and temperature. Results indicated that the growth and physiology of groupers fed with SBM were significantly negatively affected, with the gene expressions of intestinal structural protein abnormal. 16SrDNA high-throughput sequencing showed that the intestinal microflora played an important role in the pathogenesis of pearl gentian grouper SBMIE, which may activate a variety of pathogen pattern recognition receptors, such as toll-like receptors (TLRs), RIG-I-like receptors, and nod-like receptors. Transcriptome analysis revealed that changes of the SBMIE signaling pathway in pearl gentian groupers were conservative to some extent than that of terrestrial animals and freshwater fish. Moreover, the TLRs-nuclear factor kappa-B signaling pathway becomes activated, which played an important role in SBMIE. Meanwhile, the signal pathways related to nutrient absorption and metabolism were generally inhibited. Metabolomics analysis showed that isoflavones and saponins accounted for a large proportion in the potential biomarkers of pearl gentian grouper SBMIE, and most of the biomarkers had significantly positive or negative correlations with each other; 56 metabolites were exchanged between intestinal tissues and contents, which may play an important role in the development of enteritis, including unsaturated fatty acids, organic acids, amino acids, vitamins, small peptides, and nucleotides, etc. These results provide a basic theoretical reference for solving the intestinal issues of fish SBMIE and research of inflammatory bowel disease in mammals.

Endocrine disrupting chemicals (EDCs) and the neuroendocrine system: Beyond estrogen, androgen, and thyroid

Hundreds of anthropogenic chemicals occupy our bodies, a situation that threatens the health of present and future generations. This chapter focuses on endocrine disrupting compounds (EDCs), both naturally occurring and man-made, that affect the neuroendocrine system to adversely impact health, with an emphasis on reproductive and metabolic pathways. The neuroendocrine system is highly sexually dimorphic and essential for maintaining homeostasis and appropriately responding to the environment. Comprising both neural and endocrine components, the neuroendocrine system is hormone sensitive throughout life and touches every organ system in the body. The integrative nature of the neuroendocrine system means that EDCs can have multi-system effects. Additionally, because gonadal hormones are essential for the sex-specific organization of numerous neuroendocrine pathways, endocrine disruption of this programming can lead to permanent deficits. Included in this review is a brief history of the neuroendocrine disruption field and a thorough discussion of the most common and less well understood neuroendocrine disruption modes of action. Also provided are extensive examples of how EDCs are likely contributing to neuroendocrine disorders such as obesity, and evidence that they have the potential for multi-generational effects.

Endocrine disruption by dietary phyto-oestrogens: impact on dimorphic sexual systems and behaviours

A wide range of health benefits have been ascribed to soya intake including a lowered risk of osteoporosis, heart disease, breast cancer, and menopausal symptoms. Because it is a hormonally active diet, however, soya can also be endocrine disrupting, suggesting that intake has the potential to cause adverse health effects in certain circumstances, particularly when exposure occurs during development. Consequently, the question of whether or not soya phyto-oestrogens are beneficial or harmful to human health is neither straightforward nor universally applicable to all groups. Possible benefits and risks depend on age, health status, and even the presence or absence of specific gut microflora. As global consumption increases, greater awareness and consideration of the endocrine-disrupting properties of soya by nutrition specialists and other health practitioners is needed. Consumption by infants and small children is of particular concern because their hormone-sensitive organs, including the brain and reproductive system, are still undergoing sexual differentiation and maturation. Thus, their susceptibility to the endocrine-disrupting activities of soya phyto-oestrogens may be especially high. As oestrogen receptor partial agonists with molecular and cellular properties similar to anthropogenic endocrine disruptors such as bisphenol A, the soya phyto-oestrogens provide an interesting model for how attitudes about what is 'synthetic' v. what is 'natural,' shapes understanding and perception of what it means for a compound to be endocrine disrupting and/or potentially harmful. This review describes the endocrine-disrupting properties of soya phyto-oestrogens with a focus on neuroendocrine development and behaviour.

Hormonally active phytochemicals and vertebrate evolution

Living plants produce a diversity of chemicals that share structural and functional properties with vertebrate hormones. Wildlife species interact with these chemicals either through consumption of plant materials or aquatic exposure. Accumulating evidence shows that exposure to these hormonally active phytochemicals (HAPs) often has consequences for behavior, physiology, and fecundity. These fitness effects suggest there is potential for an evolutionary response by vertebrates to HAPs. Here, we explore the toxicological HAP-vertebrate relationship in an evolutionary framework and discuss the potential for vertebrates to adapt to or even co-opt the effects of plant-derived chemicals that influence fitness. We lay out several hypotheses about HAPs and provide a path forward to test whether plant-derived chemicals influence vertebrate reproduction and evolution. Studies of phytochemicals with direct impacts on vertebrate reproduction provide an obvious and compelling system for studying evolutionary toxicology. Furthermore, an understanding of whether animal populations evolve in response to HAPs could provide insightful context for the study of rapid evolution and how animals cope with chemical agents in the environment.

Estrogenicity of captive southern white rhinoceros diets and their association with fertility

The captive southern white rhinoceros (SWR) population is not currently self-sustaining, primarily due to poor or absent reproduction of captive-born (F₁₊) females. In this study, we investigate the role of dietary phytoestrogens in this reproductive phenomenon by characterizing activation of SWR estrogen receptors (ESRs) 1 and 2 by diet items from nine North American institutions and comparing female SWR fertility to total diet estrogenicity. Of the diet items tested, alfalfa hay and soy and alfalfa-based commercial pellets were found to be the most potent activators of SWR ESRs. In contrast, most grass hays tested were not estrogenic. The estrogenicity of total diets varied across the institutions surveyed and the degree of diet estrogenicity was positively associated with the percentage of the total diet comprised by pellets. Comparisons of fertility records of the institutions surveyed showed no significant relationship between diet estrogenicity and fertility for female SWR conceived or born in the wild (F₀). However, for F₁₊ females, there was a significant negative relationship between institutional diet estrogenicity and fertility. Taken together, these data suggest that developmental exposure to phytoestrogens may be the cause of poor fertility in captive-born female SWR. Whether the low fertility of the current population of captive-born female SWR is permanent or can be reversed by removing phytoestrogens from the diet remains unclear. However, our findings suggest that in order for the SWR population to become self-sustaining, the development and feeding of low phytoestrogen diets should be strongly considered.

Cytotoxic activity of genistein-8-C-glucoside form Lupinus luteus L. and genistein against human SK-OV-3 ovarian carcinoma cell line

Genistein belongs to isoflavones, which are a subclass of flavonoids, a large group of polyphenolic compounds widely distributed in plants. Numerous in vitro studies suggest that isoflavones, particularly genistein, have both chemopreventive and chemotherapeutic potential in multiple tumor types. However, the molecular and cellular mechanisms of genistein effects on human ovarian cancer cells are still little known. In the present study, we investigated anticancer activity of genistein and its natural glucoside, genistein-8-C-glucoside isolated from flowers of Lupinus luteus L. We examined the effects of the two isoflavones alone or in combination on cultured human SK-OV-3 ovarian carcinoma cells. The cells were exposed to genistein and genistein-8-C-glucoside at various concentrations (1–90 µM) for 24 and 48 h. The cytotoxic and apoptotic properties of compounds were studied by the colorimetric 3-[4,5-2-yl]-2-5-diphenyltetrazolium bromide assay and the acridine orange/ethidium bromide staining technique. The morphological features of SK-OV-3 cells were examined by Nomarski differential interference contrast combined with a confocal laser scanning microscope. The level of ROS was evaluated with fluorescence probes: dichlorofluorescein-diacetate by flow cytometry. Changes in mitochondrial membrane potential were determined using 5,5,6,6-tetrachloro-1,1,3,3-tetraethylbenzimidazolcarbocyanine iodide. Genistein-treatment and genistein-8-C-glucoside-treatment resulted in the inhibition of cell proliferation, induction of apoptotic cell death and loss of mitochondrial membrane potential. The present data provide the first evidence in vitro that genistein-8-C-glucoside and combination genistein-genistein-8-C-glucoside could be a potential chemotherapeutic candidate for ovarian cancer therapy.

Endocrine-Modulating Substances in the Environment: The Wildlife Connection

Historical observations, first publicized in Rachel Carson's Silent Spring, demonstrated biological effects of persistent, bioaccumulative pollutants on wildlife. These effects included disruption of reproduction and, in some situations, responses mediated through the endocrine system. The substances that caused these effects were mainly highly chlorinated halocarbon compounds, such as DDT (and metabolites), other organochlorine pesticides, polychlori-nated biphenyls, poly chlorinated dibenzo-p-dioxins, and poly chlorinated dibenzofurans. In contrast, responses of fish to industrial discharges and pulp mill effluents have implicated more water-soluble compounds. Characterizations of wildlife exposures require consideration of temporal and spatial factors that they exacerbate or ameliorate responses. Likewise, effects of endocrine-modulating substances m ay appear at subsequent stages of development, not at the time of exposure. Consistent with the declines in environmental concentrations of persistent, bioaccumulative substances, populations of several wild bird species, including bald eagles, cormorants, herring gulls, and Caspian terns, have increased, recovering from declines noted in previously polluted areas during the 1960s and 1970s.

Reproductive responses of male Brandt's voles (Lasiopodomys brandtii) to 6-methoxybenzoxazolinone (6-MBOA) under short photoperiod

The plant secondary metabolite 6-methoxybenzoxazolinone (6-MBOA) can stimulate and enhance animal reproduction. This compound has been successfully detected in Leymus chinensis, which is the main diet of Brandt's voles. The aim of this study was to investigate the effect of different 6-MBOA doses on the reproductive physiology of male Brandt's voles under a short photoperiod. The results showed that 6-MBOA administration increased relative testis weight, regardless of the dose, but it had little effect on the body mass. Low and middle doses of 6-MBOA increased the concentrations of luteinizing hormone and testosterone in the serum and the mRNA levels of StAR and CYP11a1 in the testes. However, 6-MBOA did not cause any significant increase in the mRNA levels of KiSS-1, GPR54, and GnRH compared to those in the control group. The mRNA level of KiSS-1 in the arcuate nucleus (ARC) was higher than that in the anteroventral periventricular nucleus (AVPV). Collectively, our results demonstrated that the number of KiSS-1-expressing neurons located in the ARC was the highest, and that 6-MBOA, which might modulate the reproductive activity along the hypothalamic-pituitary-gonadal axis, had a dose-dependent stimulatory effect on the reproductive activity of Brandt's voles under a short photoperiod. Our study provided insights into the mechanism of 6-MBOA action and the factors influencing the onset of reproduction in Brandt's voles.

Rapid Phytotransformation of Benzotriazole Generates Synthetic Tryptophan and Auxin Analogs in Arabidopsis

Benzotriazoles (BTs) are xenobiotic contaminants widely distributed in aquatic environments and of emerging concern due to their polarity, recalcitrance, and common use. During some water reclamation activities, such as stormwater bioretention or crop irrigation with recycled water, BTs come in contact with vegetation, presenting a potential exposure route to consumers. We discovered that BT in hydroponic systems was rapidly (approximately 1-log per day) assimilated by Arabidopsis plants and metabolized to novel BT metabolites structurally resembling tryptophan and auxin plant hormones; <1% remained as parent compound. Using LC-QTOF-MS untargeted metabolomics, we identified two major types of BT transformation products: glycosylation and incorporation into the tryptophan biosynthetic pathway. BT amino acid metabolites are structurally analogous to tryptophan and the storage forms of auxin plant hormones. Critical intermediates were synthesized (authenticated by (1)H/(13)C NMR) for product verification. In a multiple-exposure temporal mass balance, three major metabolites accounted for >60% of BT. Glycosylated BT was excreted by the plants into the hydroponic medium, a phenomenon not observed previously. The observed amino acid metabolites are likely formed when tryptophan biosynthetic enzymes substitute synthetic BT for native indolic molecules, generating potential phytohormone mimics. These results suggest that BT metabolism by plants could mask the presence of BT contamination in the environment. Furthermore, BT-derived metabolites are structurally related to plant auxin hormones and should be evaluated for undesirable biological effects.

Neuroendocrine regulation of gonadotropin secretion in seasonally breeding birds

Seasonally breeding birds detect environmental signals, such as light, temperature, food availability, and presence of mates to time reproduction. Hypothalamic neurons integrate external and internal signals, and regulate reproduction by releasing neurohormones to the pituitary gland. The pituitary gland synthesizes and releases gonadotropins which in turn act on the gonads to stimulate gametogenesis and sex steroid secretion. Accordingly, how gonadotropin secretion is controlled by the hypothalamus is key to our understanding of the mechanisms of seasonal reproduction. A hypothalamic neuropeptide, gonadotropin-releasing hormone (GnRH), activates reproduction by stimulating gonadotropin synthesis and release. Another hypothalamic neuropeptide, gonadotropin-inhibitory hormone (GnIH), inhibits gonadotropin synthesis and release directly by acting on the pituitary gland or indirectly by decreasing the activity of GnRH neurons. Therefore, the next step to understand seasonal reproduction is to investigate how the activities of GnRH and GnIH neurons in the hypothalamus and their receptors in the pituitary gland are regulated by external and internal signals. It is possible that locally-produced triiodothyronine resulting from the action of type 2 iodothyronine deiodinase on thyroxine stimulates the release of gonadotropins, perhaps by action on GnRH neurons. The function of GnRH neurons is also regulated by transcription of the GnRH gene. Melatonin, a nocturnal hormone, stimulates the synthesis and release of GnIH and GnIH may therefore regulate a daily rhythm of gonadotropin secretion. GnIH may also temporally suppress gonadotropin secretion when environmental conditions are unfavorable. Environmental and social milieus fluctuate seasonally in the wild. Accordingly, complex interactions of various neuronal and hormonal systems need to be considered if we are to understand the mechanisms underlying seasonal reproduction.

Effects of environmental endocrine disruptors and phytoestrogens on the kisspeptin system

Sex steroid hormones, most notably estradiol, play a pivotal role in the sex-specific organization and function of the kisspeptin system. Endocrine--disrupting compounds are anthropogenic or naturally occurring compounds that interact with steroid hormone signaling. Thus, these compounds have the potential to disrupt the sexually dimorphic ontogeny and function of kisspeptin signaling pathways, resulting in adverse effects on neuroendocrine physiology. This chapter reviews the small but growing body of evidence for endocrine disruption of the kisspeptin system by the exogenous estrogenic compounds bisphenol A, polychlorinated biphenyl mixtures, and the phytoestrogen genistein. Disruption is region, sex, and compound specific, and associated with shifts in the timing of pubertal onset, irregular estrous cycles, and altered sociosexual behavior. These effects highlight that disruption of kisspeptin signaling pathways could have wide ranging effects across multiple organ systems, and potentially underlies a suite of adverse human health trends including precocious female puberty, idiopathic infertility, and metabolic syndrome.

Estrogenic plant consumption predicts red colobus monkey (Procolobus rufomitratus) hormonal state and behavior

Numerous studies have examined the effects of anthropogenic endocrine disrupting compounds; however, very little is known about the effects of naturally occurring plant-produced estrogenic compounds (i.e., phytoestrogens) on vertebrates. To examine the seasonal pattern of phytoestrogen consumption and its relationship to hormone levels (407 fecal samples analyzed for estradiol and cortisol) and social behavior (aggression, mating, and grooming) in a primate, we conducted an 11-month field study of red colobus (Procolobus rufomitratus) in Kibale National Park, Uganda. The percent of diet from estrogenic plants averaged 10.7% (n=45 weeks; range: 0.7-32.4%). Red colobus fed more heavily on estrogenic Millettia dura young leaves during weeks of higher rainfall, and the consumption of this estrogenic item was positively correlated to both their fecal estradiol and cortisol levels. Social behaviors were related to estradiol and cortisol levels, as well as the consumption of estrogenic plants and rainfall. The more the red colobus consumed estrogenic plants the higher their rates of aggression and copulation and the lower their time spent grooming. Our results suggest that the consumption of estrogenic plants has important implications for primate health and fitness through interactions with the endocrine system and changes in hormone levels and social behaviors.

Soy, phytoestrogens and their impact on reproductive health

There is growing interest in the potential health threats posed by endocrine-disrupting chemicals (EDCs) to the reproductive system. Soybean is the most important dietary source of isoflavones, an important class of phytoestrogen. While consumption of soy food or phytoestrogen supplements has been frequently associated with beneficial health effects, the potentially adverse effects on development, fertility, and the reproductive and endocrine systems are likely underappreciated. Here we review the available epidemiological, clinical and animal data on the effects of soy and phytoestrogens on the development and function of the male and female reproductive system, and weigh the evidence as to their detrimental impact.

Estrogenic plant foods of red colobus monkeys and mountain gorillas in Uganda

Phytoestrogens, or naturally occurring estrogen-mimicking compounds, are found in many human plant foods, such as soybeans (Glycine max) and other legumes. Because the consumption of phytoestrogens may result in both health benefits of protecting against estrogen-dependent cancers and reproductive costs of disrupting the developing endocrine system, considerable biomedical research has been focused on the physiological and behavioral effects of these compounds. Despite this interest, little is known about the occurrence of phytoestrogens in the diets of wild primates, nor their likely evolutionary importance. We investigated the prevalence of estrogenic plant foods in the diets of two folivorous primate species, the red colobus monkey (Procolobus rufomitratus) of Kibale National Park and mountain gorilla (Gorilla beringei) of Bwindi Impenetrable National Park, both in Uganda. To examine plant foods for estrogenic activity, we screened 44 plant items (species and part) comprising 78.4% of the diet of red colobus monkeys and 53 plant items comprising 85.2% of the diet of mountain gorillas using transient transfection assays. At least 10.6% of the red colobus diet and 8.8% of the gorilla diet had estrogenic activity. This was mainly the result of the red colobus eating three estrogenic staple foods and the gorillas eating one estrogenic staple food. All estrogenic plants exhibited estrogen receptor (ER) subtype selectivity, as their phytoestrogens activated ERβ, but not ERα. These results demonstrate that estrogenic plant foods are routinely consumed by two folivorous primate species. Phytoestrogens in the wild plant foods of these two species and many other wild primates may have important implications for understanding primate reproductive ecology.

Mechanism of phytoestrogen action in Leydig cells of ganders (Anser anser domesticus): Interaction with estrogen receptors and steroidogenic enzymes

Phytoestrogens (PE) are plant-derived compounds that have an estrogen-like activity and they can influence male and female reproduction. The possible mechanisms of PE action may be including: the binding to estrogen receptors (ER) and the interaction with the key steroidogenic enzymes. The aim of this study was to investigate if PE has effect on steroidogenesis of gander testicular cells by above-described pathways. The Leydig cells were isolated from testes of White Kołuda ganders at the peak of their reproductive activity (March). These Leydig cells (1 × 10(5)per mL) were pre-incubated with the ER inhibitor - ICI 182, 780 (100 nM) for 3 h and then these cells were incubated with PE (5 and 50 μM): genistein, daidzein, equol and coumestrol during next 20 h or untreated control and the Leydig cells that were previously treated (20 h) with genistein (5 and 50 μM) were incubated for next 6 h with steroid intermediates (20 μM) as testosterone (T) precursors: hydroxycholesterol, pregnenolone, progesterone and androstenedione. Concentrations of T in the samples of incubation medium were measured using radioimmunoassay. Genistein, daidzein, and equol (5 and 50 μM) decreased (P < 0.05) T secretion by incubated gander Leydig cells and ICI 182, 780 did not eliminate the inhibitory effect of these PE. After genistein (50 μM) treatment, basal and stimulated with 22R-hydroxycholesterol, pregnenolone, progesterone and androstenedione, T production by testicular cells was decreased (P < 0.05). In contrast, genistein at lower dose (5 μM) did not affect the stimulatory effects of testosterone precursors. In conclusion, the inhibition of testosterone secretion by the phytoestrogens in gander Leydig cells did not depend on estrogen receptors. The suppression of steroidogenesis in these cells may be in part conducted by interaction of phytoestrogens with key steroidogenic enzymes. However, further studies are required to elucidate the phytoestrogen mechanism of action in gander testicular cells.

Phytochemicals and reproductive function in wild female Phayre's leaf monkeys (Trachypithecus phayrei crepusculus)

Female reproduction is known to be influenced by food availability and its impact on energetic status. However, emerging evidence suggests that the phytochemical content of food may also be an important factor. Here, we investigated this hypothesis, presenting 20 months of data on fecal progestin (fP) patterns in wild female Phayre's leaf monkeys (Trachypithecus phayrei crepusculus). We examined whether (a) the availability of Vitex (a plant known to contain phytochemicals) might be linked to seasonal fP levels, (b) fP levels were associated with female reproductive performance, and (c) reproductive performance might also be linked with energetic status (as measured by physical condition). We collected fecal samples (N=2077) from 10 adult females to analyze estrogen (fE) and progestin (fP) metabolites, behavioral data from 7 cycling females to determine receptivity, and monthly data on Vitex availability and female physical condition. Seasonally elevated fP levels were found in all females, with higher levels when Vitex leaves and fruits were abundant. During the period of high progestins, females had longer cycle lengths and follicular phases, while receptive periods did not change. Nevertheless, when ovulations occurred, females were more likely to conceive. On the other hand, conceptions were also more likely when physical condition was improving, suggesting that the effects of phytochemicals and energetic status on reproduction may be difficult to separate. Although our results support the predicted effects of Vitex on endocrine and reproductive function, future studies with detailed feeding data and chemical analyses of plants are needed to confirm this finding.

Phytoestrogens and mycotoxins in Iowa streams: an examination of underinvestigated compounds in agricultural basins

This study provides the first broad-scale investigation on the spatial and temporal occurrence of phytoestrogens and mycotoxins in streams in the United States. Fifteen stream sites across Iowa were sampled five times throughout the 2008 growing season to capture a range of climatic and crop-growth conditions. Basin size upstream from sampling sites ranged from 7 km2 to > 836,000 km2. Atrazine (herbicide) also was measured in all samples as a frame-of-reference agriculturally derived contaminant. Target compounds were frequently detected in stream samples: atrazine (100%), formononetin (80%), equol (45%), deoxynivalenol (43%), daidzein (32%), biochanin A (23%), zearalenone (13%), and genistein (11%). The nearly ubiquitous detection of formononetin (isoflavone) suggests a widespread agricultural source, as one would expect with the intense row crop and livestock production present across Iowa. Conversely, the less spatially widespread detections of deoxynivalenol (mycotoxin) suggest a more variable source due to the required combination of proper host and proper temperature and moisture conditions necessary to promote Fusarium spp. infections. Although atrazine concentrations commonly exceeded 100 ng L(-1) (42/75 measurements), only deoxynivalenol (6/56 measurements) had concentrations that occasionally exceeded this level. Temporal patterns in concentrations varied substantially between atrazine, formononetin, and deoxynivalenol, as one would expect for contaminants with different source inputs and processes of formation and degradation. The greatest phytoestrogen and mycotoxin concentrations were observed during spring snowmelt conditions. Phytoestrogens and mycotoxins were detected at all sampling sites regardless of basin size. The ecotoxicological effects from long-term, low-level exposures to phytoestrogens and mycotoxins or complex chemicals mixtures including these compounds that commonly rake place in surface water are poorly understood and have yet to be systematically investigated in environmental studies.

Effect of daidzein on egg-laying performance in Shaoxing duck breeders during different stages of the egg production cycle

The effect of a phyto-oestrogen, daidzein, on the laying performance of Shaoxing female ducks was examined in three experiments performed at different stages of the egg production cycle. Egg-laying rate, egg weight, egg composition, feed conversion ratio, hatchability characteristics of eggs and body weight, ovary and oviduct weight, as well as changes in serum concentrations of T3, T4 and E2 were recorded as response criteria. In the first experiment, 68 young ducks, 100 d of age, were given a basal diet (maize-soybean meal) with or without 3 mg of daidzein/kg diet for 42 d. Daidzein did not affect the onset of lay but apparently decreased egg-laying rate and mean egg weight as well as the feed conversion ratio. In the second experiment, 240 breeding ducks, 402 d of age, were allotted at random to three groups and given the basal diet containing daidzein at 0 (control), 3 (Da1) and 5mg/kg (Da2) for 35d. Egg-laying rate, mean egg weight and feed conversion ratio increased in both Da1 and Da2 groups. However, an adverse effect of daidzein on fertility and hatchability was observed. In the third experiment, 320 breeding ducks, 415 d of age, were fed on the basal diet with or without 5mg of daidzein/kg diet for 63 d. Egg-laying rate increased by 7.7%, average egg weight tended to increase, whereas yolk/albumen ratio decreased. Daidzein-treated ducks had higher body weight and oviduct weight compared with their controls. Elevated plasma T4 and E2 concentrations accompanied these phenotypic changes, but serum T3 was not affected. It is suggested that daidzein exerts divergent effects on the egg-laying performance of Shaoxing ducks under different physiological conditions and this action is dose-dependent. The changes in circulating E2 imply possible participation of endogenous oestrogen in the mechanism of daidzein action.

Influence of sex hormones and phytoestrogens on heart disease in men and women

Cardiovascular disease (CVD) is the number one cause of morbidity and mortality in men and women worldwide. According to the WHO, by 2015, almost 20 million people will die from CVD each year. It is well established that men and women differ not only in baseline cardiac parameters, but also in the clinical presentation, diagnosis and treatment outcomes of CVD. Women tend to develop heart disease later in life than men. This difference has been attributed to the loss of estrogen during the menopausal transition; however, the biological explanations for the sexual dimorphism in CVD are more complex and seem unlikely to be due to estrogen alone. The current controversy that has arisen regarding the effects of HRT on CVD in women is a case in point. In this review, the sex-based differences in cardiac (patho-) physiology are discussed with emphasis on the impact of sex hormones, hormone receptors and diet on heart disease.

Soy, phyto-oestrogens and male reproductive function: a review

There is growing interest in the possible health threat posed by the effects of endocrine disruptors on reproduction. Soy and soy-derived products contain isoflavones that mimic the actions of oestrogens and may exert adverse effects on male fertility. The purpose of this review was to examine the evidence regarding the potential detrimental effects of soy and phyto-oestrogens on male reproductive function and fertility in humans and animals. Overall, there are some indications that phyto-oestrogens, alone or in combination with other endocrine disruptors, may alter reproductive hormones, spermatogenesis, sperm capacitation and fertility. However, these results must be interpreted with care, as a result of the paucity of human studies and as numerous reports did not reveal any adverse effects on male reproductive physiology. Further investigation is needed before a firm conclusion can be drawn. In the meantime, caution would suggest that perinatal phyto-oestrogen exposure, such as that found in infants feeding on soy-based formula, should be avoided.

Sex-based cardiac physiology

Biological sex plays an important role in normal cardiac physiology as well as in the heart's response to cardiac disease. Women generally have better cardiac function and survival than do men in the face of cardiac disease; however, this sex difference is lost when comparing postmenopausal women with age-matched men. Animal models of cardiac disease mirror what is seen in humans. Sex steroid hormones contribute significantly to sex-based differences in cardiac disease outcomes. Estrogen is generally considered to be cardioprotective, whereas testosterone is thought to be detrimental to heart function. Environmental estrogen-like molecules, such as phytoestrogens, can also affect cardiac physiology in both a positive and a negative manner.

Phytoestrogens and avian reproduction: Exploring the evolution and function of phytoestrogens and possible role of plant compounds in the breeding ecology of wild birds

Phytoestrogens are secondary plant compounds, which can act to mimic estrogen and cause the disruption of estrogenic responses in organisms. Although there is a substantial body of research studying phytoestrogens, including their mechanisms of estrogenic effects, evolution, and detection in biological systems, little is known about their ecological significance. There is evidence, however, that an ecological relationship involving phytoestrogens exists between plants and animals-plants may produce phytoestrogens to reduce fecundity of organisms that eat them. Birds and other vertebrates may also exploit phytoestrogens to regulate their own reproduction-there are well known examples of phytoestrogens inhibiting reproduction in higher vertebrates, including birds. Also, common plant stressors (e.g., high temperature) increase the production of secondary plant compounds, and, as evidence suggests, also induce phytoestrogen biosynthesis. These observations are consistent with the single study ever done on phytoestrogens and reproduction in wild birds [Leopold, A.S., Erwin, M., Oh, J., Browning, B., 1976. Phytoestrogens adverse effects on reproduction in California quail. Science 191, 98-100.], which found that drought stress correlated with increased levels of phytoestrogens in plants, and that increased phytoestrogen levels correlated with decreased young. This review discusses the hypothesis that plants may have an effect on the reproduction of avian species by producing phytoestrogens as a plant defense against herbivory, and that birds may "use" changing levels of phytoestrogens in the vegetation to ensure that food resources will support potential young produced. Evidence from our laboratory and others appear to support this hypothesis.

Exploitation of secondary metabolites by animals: A response to homeostatic challenges

We propose that the exploitation of the bioactive properties of secondary metabolites (SMs) by animals can provide a "treatment" against various challenges that perturb homeostasis in animals. The unified theoretical framework for the exploitation of SMs by animals is based on a synthesis of research from a wide range of fields and although it is focused on providing generalized predictions for herbivores that exploit SMs of plants, predictions can be applied to understand the exploitation of SMs by many animals. In this review, we argue that the probability of SM exploitation is determined by the relative difference between the cost of a homeostatic challenge and the toxicity of the SM and we provide various predictions that can be made when considering behavior under a homeostatic perspective. The notion that animals experience and respond to costly challenges by exploiting therapeutic SMs provides a relatively novel perspective to explain foraging behavior in herbivores, specifically, and behavior of animals in general. We provide evidence that animals can exploit the biological activity of SMs to mitigate the costs of infection by parasites, enhance reproduction, moderate thermoregulation, avoid predation, and increase alertness. We stress that a better understanding of animal behavior requires that ecologists look beyond their biases that SMs elicit punishment and consider a broader view of avoidance or selection of SMs relative to the homeostatic state. Finally, we explain how understanding exploitation of SMs by animals could be applied to advance practices of animal management and lead to discovery of new drugs.

Dietary red clover (Trifolium pratense) induces oviduct growth and decreases ovary and testes growth in Japanese quail chicks

To determine whether drought-stress alters phytoestrogens in red clover and whether red clover in the diet influences sexual development in Japanese quail, we fed chicks diets containing irrigated or non-irrigated clover. Irrigation altered phytoestrogenic activity of red clover (determined using an in vitro bioassay), with extracts of irrigated clover diet containing more estrogenic activity than extracts of non-irrigated clover diet. Chick growth was negatively correlated with the amount of irrigated or non-irrigated clover in the diet. Dietary red clover also depressed both absolute and relative gonad weights; however, relative oviduct weight was increased by the irrigated diet. Diets did not affect serum vitellogenin. These results reveal a negative influence of drought-stress on phytoestrogenic potency of clover, and that red clover in the diet can inhibit avian growth and development independent of irrigation state. Thus, phytoestrogens may affect reproductive development in wild birds, and environmental stressors may influence levels of phytoestrogens in the field.

Effects of dietary meals containing different levels of phytoestrogens on reproductive function in Bilgoraj ganders

The aim of this study was to investigate how long-term feeding of ganders with diets containing different levels of phytoestrogens affects the morphometry of testes, plasma steroid levels, sperm parameters and reproductive performance. Male Bilgoraj geese were fed diets containing grass meal (with low phytoestrogen levels) and those containing alfalfa meal and soybean meal (with higher levels of phytoestrogens). Testes were obtained from ganders at the peak of mating and the ongoing laying period as well as at the beginning of photorefractoriness. The morphometric parameters were measured in frozen testicular sections. Blood was collected monthly from December to June, and plasma testosterone, androstenedione and corticosterone concentrations were determined. During the mating season, semen was collected and its quantity and quality were investigated. In the flocks (ganders with geese) reproductive output was noted. Seasonal changes were observed in the morphology of testes and in plasma testosterone, androstenedione and corticosterone concentrations in ganders. The feeding of ganders with dietary meals containing higher levels of phytoestrogens did not affect the plasma steroid contents or the majority of the morphometric parameters of testes, except for the height of the seminiferous epithelium, which was lowered. Moreover, diets with higher levels of phytoestrogens decreased the volume of ejaculates and the percentage of normal spermatozoa. However, these changes were not reflected in the fertilisation rates.

The effects of ACTH, phytoestrogens and estrogens on corticosterone secretion by gander adrenocortical cells in breeding and nonbreeding seasons

The aim of this study was to investigate the effects of ACTH, phytoestrogens (genistein, daidzein, biochanin A and coumestrol), and animal estrogens (estradiol and estrone) on corticosterone secretion by isolated adrenocortical cells of the ganders in breeding (April) and nonbreeding seasons (July). ACTH stimulated corticosterone output in the breeding season. In July (photorefractoriness and postbreeding molt) ACTH had no effect on corticosterone production. Coumestrol reduced corticosterone secretion by the cells obtained in nonbreeding season. Other examined phytoestrogens did not affect corticosterone production. Estrogens showed differentiated effects. Estradiol stimulated the corticosterone output in breeding season; estrone inhibited corticosterone release in July. The season can probably affect sensitivity of isolated gander adrenal cells, especially to ACTH. It seems that goose adrenocortical cells, in contrast to the mammalian cells, can be weakly sensitive to phytoestrogens.

Effects of daidzein on messenger ribonucleic Acid expression of gonadotropin receptors in chicken ovarian follicles

Effects of daidzein on expression of mRNA of gonadotropin receptors [follicle-stimulating hormone receptor (FSHR), luteinizing hormone receptor (LHR)] were evaluated in ovarian follicles of ISA laying hens that were 13 mo old in the postpeak period of egg laying. The hens were randomly allocated as control and daidzein-treated groups, with daidzein supplemented to the basal diet at the level of 10 mg/kg for 7 wk. The granulosa layers of preovulatory follicles (F1, F2, F3, F4, F5) and follicular layers of the small yellow follicle (SYF), large white follicle (LWF), and atretic follicle were collected. The mRNA expression of related genes was measured by semiquantitative reverse transcription PCR. Results showed that daidzein significantly increased the egg-laying rate (P < 0.05) and the number of SYF and LWF (P < 0.05). The relative abundance of the FSHR mRNA decreased in the granulosa layers from F5 to F1, but LHR mRNA displayed the opposite trend in developmental changes. Treatment with daidzein resulted in increased expression of FSHR mRNA in LWF, SYF, and granulosa layers of F4 to F2 and LHR mRNA in granulosa layers of F4 and F1 (P < 0.05). These results indicated that dietary supplementation of daidzein upregulated mRNA expression of gonadotropin receptors to improve follicle development in chicken developing follicles and laying performance after the peak laying period.

Digit ratio unaffected by estradiol treatment of zebra finch nestlings

There is rapidly growing evidence that the relative length of the second to fourth digit (digit ratio) in human hands is correlated with a large number of physiological and behavioral traits that are influenced by sex hormones. However, it is still unclear why these correlations exist. Very recently, similar correlations with relative toe lengths have been found in other vertebrate species including the zebra finch (Taeniopygia guttata). These non-human study organisms allow us to test experimentally various hypotheses regarding the mechanisms responsible for these patterns. In the present paper we first attempt to clarify the various hypotheses that have been proposed regarding the pleiotropic factor that is thought to affect both, the digits and the sex-hormone dependent physiology and behavior. We then present an experimental test of one specific hypothesis, namely that high levels of estradiol during the main growth period affect the relative size of the second vs. fourth toe. Twenty-three zebra finch nestlings from nine different families were treated daily (days 5-11 posthatch) with a high oral dose of estradiol benzoate administered by gavage. While the treatment had clear effects on the birds' reproductive physiology in adulthood (shown elsewhere), we found no significant effect on their digit ratio compared to control birds. At best, the effect could have been very small or restricted to certain genotypes. Hence, it seems unlikely that the estradiol level during the main growth phase is the pleiotropic agent that causes digit ratio to correlate with sex-hormone dependent behavioral and physiological traits.

Evaluation of reproductive safety of beta-sitosterol on the American mink (Neovison vison)

beta-Sitosterol is a weakly estrogenic phytosterol used extensively in functional foods to lower elevated serum cholesterol concentrations due to its inhibitory action on intestinal cholesterol absorption. It caused previously decreased sex steroid concentrations in fish and lowered sperm counts in rats. In the American mink (Neovison vison), litter size increased slightly due to dietary beta-sitosterol supplement. The aim of the present experiment was to conduct a dose-response study on the effects of beta-sitosterol on the reproduction of the American mink. Juvenile male and female mink (n=480) were exposed to 0, 5, 10 or 50 mg of peroral beta-sitosterol kg(-1)d(-1) for 10 months. After 3 months of exposure in November, 15 males per group were sacrificed and general biochemical variables reflecting overall health were determined. The beta-sitosterol-treated male mink had increased absolute and relative masses of intraabdominal fat and higher blood hemoglobin and serum high-density lipoprotein cholesterol concentrations. In spring, the top-rated male mink were mated with multiple females within each study group and reproductive success was assessed. No differences in the reproductive performance of the males (10-11 per group) or females (47-50 per group) could be detected in the exposed groups and the kits of all groups developed in a similar manner. The results suggest that dietary beta-sitosterol presents no significant risk to mammalian fertility.

VIEWPOINT. An hypothesis to explain the linkage between kakapo (Strigops habroptilus) breeding and the mast fruiting of their food trees

An important goal in the intensive conservation management of New Zealand’s critically endangered nocturnal parrot, kakapo (Strigops habroptilus), is to increase the frequency of breeding attempts. Kakapo breeding does not occur annually but rather correlates with 3–5-year cycles in ‘mast’ seeding/fruiting of kakapo food plants, most notably podocarps such as rimu (Dacrydium cupressinum). Here we advance a hypothetical mechanism for the linking of kakapo breeding with such ‘mast’ seeding/fruiting. The essence of the hypothesis is that exposure to low levels of dietary phytochemicals may, in combination with hepatic gene ‘memory’, sensitise egg yolk protein genes, expressed in female kakapo livers, to oestrogens derived from developing ovarian follicles. Only in those years when the egg yolk protein genes have been sufficiently ‘pre-sensitised’ by dietary chemicals do kakapo ovarian follicles develop to ovulation and egg-laying occurs. While speculative, this hypothesis is both physiologically and evolutionarily plausible and suggests both future research directions and relatively simple interventions that may afford conservation workers some influence over kakapo breeding frequency.

Dietary phytoestrogens and photoperiodic response in a male songbird, the Dark-eyed Junco (Junco hyemalis)

Many commercial bird diets are made with soy products that contain phytoestrogens (i.e., plant compounds that have weak agonist activity at estrogen receptors), but the effects of these compounds on bird physiology and behavior are largely unknown. The primary phytoestrogens present in soy are the isoflavones genistin and diadzin, which have been shown to affect reproductive measures in many taxa. Two groups of wild-caught male Dark-eyed Juncos (Junco hyemalis) were fed a diet either made with water-washed soy protein (soy(+)) or made with soy protein that had been alcohol-washed to extract isoflavones (soy(-)). Both groups exhibited a photoperiodic response to long days. Plasma luteinizing hormone (LH) concentrations increased within the first week of long day (LD) exposure for both groups, and over the course of the experiment LH was higher in the soy(+) group, although concentrations for both groups were lower than have been reported in free-living juncos. The rate of cloacal protuberance (CP) growth was significantly affected by diet, with the soy(-) birds beginning to increase their CPs about a week faster than soy(+) birds after exposure to LD. There was no group difference in food intake, fat score, body mass, or behavioral measures during the study or in testis weight at the end of the study. Although effects of dietary phytoestrogens detected were subtle (i.e., rate of CP growth), those investigating subtle effects of hormonally active substances (e.g., endocrine disruptors) or environmental cues affecting the reproductive axis in songbirds may want to consider eliminating phytoestrogens from their experimental diets.

Reduced reproductive function in wild baboons (Papio hamadryas anubis) related to natural consumption of the African black plum (Vitex doniana)

Several authors have suggested that the consumption of plant compounds may have direct effects on wild primate reproductive biology, but no studies have presented physiological evidence of such effects. Here, for two troops of olive baboons (Papio hamadryas anubis) at Gashaka-Gumti National Park, Nigeria, we show major seasonal increases in levels of fecal progesterone metabolites in females, and provide evidence that this is linked to the consumption of natural plant compounds. Increases in fecal progestogen excretion occurred seasonally in all females, in all reproductive states, including lactation. Detailed feeding data on the study animals showed that only one food species is consumed by both troops at the time of observed progestogen peaks, and at no other times of the year: the African black plum, Vitex doniana. Laboratory tests demonstrated the presence of high concentrations of progestogen-like compounds in V. doniana. Together with published findings linking the consumption of a related Vitex species (Vitex agnus castus) to increased progestogen levels in humans, our data suggest that natural consumption of V. doniana was a likely cause of the observed increases in progestogens. Levels of progestogen excretion in the study baboons during periods of V. doniana consumption are higher than those found during pregnancy, and prevent the expression of the sexual swelling, which is associated with ovulatory activity. As consortship and copulatory activity in baboons occur almost exclusively in the presence of a sexual swelling, V. doniana appears to act on cycling females as both a physiological contraceptive (simulating pregnancy in a similar way to some forms of the human contraceptive pill) and a social contraceptive (preventing sexual swelling, thus reducing association and copulation with males). The negative effects of V. doniana on reproduction may be counter-balanced by the wide-range of medicinal properties attributed to plants in this genus. This is the first time that physiological evidence has been presented of direct effects of plant consumption on the reproductive biology of wild primates.

Effect of dietary daidzein on egg production, shell quality, and gene expression of ER-alpha, GH-R, and IGF-IR in shell glands of laying hens

Our previous studies demonstrated that dietary daidzein improves egg production in ducks during the late period of the laying cycle. The present study was aimed to investigate the effect of daidzein in laying hens, with more focus on eggshell quality. The expression of ER-alpha, GH-R, and IGF-IR mRNA in shell glands was determined to identify the target genes of daidzein action and to reveal the relationship between shell quality and profiles of gene expression in shell glands of laying hens. 1000 ISA hens, at 445 days of age, were allotted at random to two groups and given the basal diet with or without 10 mg of daidzein per kg diet for 9 weeks. Daidzein supplement significantly increased the egg laying rate and the feed conversion ratio. The eggshell thickness increased, while the percentage of cracked eggs decreased in daidzein-treated hens. Serum E2 and phosphate concentrations were not altered, but the level of serum Ca2+ and the tibia bone mineral density were significantly increased in the daidzein-treated group compared with their control counterparts. In parallel with the significant increase of oviduct weight, significant down-regulation of GH-R and IGF-IR mRNA and a trend of decrease in ERalpha mRNA expression in shell glands were observed in daidzein-treated hens. The results indicate that dietary daidzein improves egg laying performance and eggshell quality during the late (postpeak) laying stage of hens, which is associated with modulations in gene expression in the shell gland.

Estrogen receptor agonists and immune system in ovariectomized mice

Several data implicate the immune system in bone lost after estrogen deficiency, however, some of the effects on the immune system of estrogen deficiency or of estrogen receptor (ER) modulation are not well established. In this study, the effect of ER agonists on the immune system in ovariectomized mice is analyzed. Mice were ovariectomized and were administered 17beta-estradiol (E2), raloxifene (RAL) or genistein (GEN). The effect of a 4-week treatment on bone turnover and on several parameters that reflect the status of the immune system was studied. Results show that ovariectomy provoked both uterine atrophy and thymic hypertrophy. Although RAL corrected thymic hypertrophy, only E2 corrected both. Ovariectomized mice showed increased levels of serum calcium and cathepsin K gene expression and decreased levels of serum alkaline phosphatase (ALP) activity, which suggests that there is a persistent alteration in bone metabolism. Moreover, ovariectomy increased B-cells and CD25+ cells, and decreased the percentages of T-cells and Cbfa1 gene expression in bone marrow (BM). All ER agonists corrected, although to different degrees, changes induced by the ovariectomy. Furthermore, results showed that it is essential to adjust ER agonist doses to avoid immunosuppression, since all ER agonists decreased BM T-cell levels.

Effects of early embryonic exposure to genistein on male copulatory behavior and vasotocin system of Japanese quail

Genistein is a phytoestrogen, particularly abundant in soybeans that can bind estrogen receptors and sex hormone binding proteins, exerting both estrogenic and antiestrogenic activity. In this study we used the Japanese quail embryo as a test end-point to investigate the effects of early embryonic exposure to genistein on male copulatory behavior and on vasotocin parvocellular system. Both differentiate by the organizational effects of estradiol during development and may therefore represent an optimal model to study the effects of xenoestrogens. We injected two doses of genistein (100 and 1000 microg) into the yolk of 3-day-old Japanese quail eggs. Other eggs were treated with either 25 microg of estradiol benzoate or sesame oil as positive and negative controls. At the age of 6 weeks, behavioral tests revealed a significant decrease of all aspects of copulatory behavior (in comparison to the control group) in estradiol-treated birds. In contrast, genistein-treated animals demonstrated various degrees of decrease in the mean frequencies of some aspects of the sexual behavior. The computerized analysis of vasotocin innervation in medial preoptic, stria terminalis and lateral septum nuclei revealed a statistically significant decreased immunoreactivity in treated animals compared to control ones. These results demonstrate that genistein, similarly to estradiol, has an organizational effect on quail parvocellular vasotocin system and on copulatory behavior. In conclusion, present results confirm, in this avian model, that embryonic exposure to phytoestrogens may have life-long effects on sexual differentiation of brain structures and behaviors.

Effects of phytoestrogens on testosterone secretion by Leydig cells from Biłgoraj ganders (Anser anser)

The aim of this study was to examine ganders at different stages of the reproductive season and the effect of: (1) diets with high phytoestrogen content and (2) in vitro phytoestrogen treatment on testosterone secretion by isolated Leydig cells. Thirty-six male Biłgoraj geese were fed control diets with low phytoestrogen content (containing grass meal) and diets with high phytoestrogens (containing alfalfa meal and soy). Testes were obtained from both groups of ganders at three different times of the breeding season: peak of reproductive activity (March), second half of reproductive activity (May) and beginning of photorefractoriness (July). Isolated Leydig cells were incubated with LH as well as genistein, daidzein, equol and coumestrol and the concentration of testosterone in the medium was determined by radioimmunoassay. The mean weight of testes from ganders in May and July decreased relative to their weights in March, but no significant differences among experimental groups were noted. No differences were observed in basal and LH-stimulated testosterone secretion by Leydig cells of ganders fed the control diets and the diets with higher phytoestrogen content. In July, LH did not stimulate testosterone secretion in either group. In vitro treatment with genistein, daidzein and equol (5 and 50 microM) inhibited basal and LH-stimulated testosterone production by Leydig cells from both groups. Coumestrol (5 and 50 microM) inhibited basal testosterone secretion only in March in the control group. Dietary exposure to phytoestrogens had a slight effect on in vitro testicular secretion in ganders. In vitro treatment with phytoestrogen inhibited testosterone production by Leydig cells. Genistein showed the strongest effect and coumestrol had the weakest influence on testicular secretion.

Lack of Estrogenic or Antiestrogenic Actions of Soy Isoflavones in an Avian Model: The Japanese Quail

Isoflavones are soy compounds that possess weak estrogenic and antiestrogenic activities. In addition, phytochemicals, including isoflavones, may play a role in regulating seasonal reproductive cycles. As soy is a common constituent in poultry diets, the effect of these compounds on the reproductive system of production birds may be of concern. The present study examined the putative effects of soy isoflavones supplemented into the diet at 1 and 5% using endpoints of growth and reproduction in the Japanese quail. Isoflavones did not exert an effect on growth, feed intake, growth:feed, or the weight of the estrogen-sensitive immature oviduct in female quail. Furthermore, isoflavones did not influence the growth of the oviduct stimulated by exogenous estradiol. Similarly, isoflavones did not influence growth, feed intake, or growth:feed in male quail. However, isoflavones at 1%, but not 5%, in the diet reduced photoperiod-induced testis development 40% vs. control. In contrast, isoflavones did not influence testis regression stimulated by exogenous estradiol in sexually maturing male quail. The present results suggest that isoflavones may exert modest endocrine disruptor-like effects on reproduction in male, but not female, quail.

Nutritional Evaluation of Raw and Extruded Kidney Bean (Phaseolus vulgaris L. var. Pinto) in Chicken Diets

An experiment was conducted to study the effect of inclusion of different concentrations (0, 100, 200, and 300 g/kg) of raw kidney bean and extruded kidney bean in broiler chick (0 to 21 d of age) diets on performance, digestive organ sizes, protein and amino acid digestibilities, intestinal viscosity, cecal pH, and blood parameters. Data were analyzed as a 3 x 2 factorial arrangement with 3 levels of kidney bean with and without extrusion. Positive control without kidney bean was used. Increasing the kidney bean content in the diet reduced weight gain and consumption, and increased the feed-to-gain ratio. Relative pancreas, liver, and jejunum weights, and intestinal viscosity were increased in response to increasing kidney bean concentration in the diet. The inclusion of different concentrations of kidney bean did not affect the apparent ileal digestibility of essential and nonessential amino acids, except for Met, Phe, and Cys, which were increased. Increasing kidney bean in the diet did not affect blood parameters, except for total protein, which was increased, and for androstenedione and testosterone, which were reduced. Extrusion significantly improved weight gain, feed consumption, and feed conversion. Relative pancreas, liver, and jejunum weights were reduced and spleen weight, cecal and intestinal viscosity were increased by extrusion. Apparent ileal digestibility of crude protein and all essential and nonessential amino acids were improved by extrusion. Like-wise, extrusion increased significantly the concentrations of cholesterol, triglycerides, glucose, and testosterone. We concluded that the inclusion of kidney bean in chicken diets cause a negative effect on performance and CP and amino acid digestibilities, and modified digestive organ sizes, intestinal viscosity, cecal pH, and some blood parameters. These effects were counteracted by the extrusion of kidney bean. However, the inclusion of extruded kidney bean in a chick diet resulted in poorer performance compared with that obtained with a corn-soybean diet.

Beauty product-related exposures and childhood brain tumors in seven countries: results from the SEARCH International Brain Tumor Study

Data from 1218 cases of childhood brain tumors (CBT) diagnosed between 1976 and 1994 and 2223 matched controls from the general population were included in an analysis of maternal beauty product exposure and beauty-related employment in 9 centers in 7 countries. A 50% increased odds ratio (OR) [95% confidence interval (CI) = 1.0-2.1] for CBT was observed among children of mothers who were exposed via personal use of and/or possible ambient contact with beauty products during the 5 years preceding the index child's birth compared with children of mothers never exposed to beauty products during this time period. Overall maternal personal use of hair-coloring agents in the month before or during the pregnancy of the index child's birth was not associated with CBT (OR = 1.0, CI = 0.83-1.3) or with astroglial (OR = 1.1, CI = 0.85-1.4), PNET (OR = 1.0, CI = 0.71-1.5) and other glial subtypes (OR = 1.0, CI = 0.62-1.0). Similarly, no statistically increased ORs or discernable pattern of risk estimates were observed for period of use or for number of applications per year for maternal personal use of hair-coloring agents overall or by histologic type. Among children born on or after 1980, increased ORs for CBT were associated with maternal non-work-related exposure to any beauty products (OR = 2.6, CI = 1.2-5.9), hair-dyes (OR = 11, CI = 1.2-90), and hair sprays (OR = 3.4, CI = 1.0-11). No overall increased OR for CBT was observed among children of mothers employed in beauty-related jobs during the 5 years preceding the index child's birth compared with those who reported no beauty-related employment. In general, other specific beauty product-related exposures were not associated with increased ORs for CBT. Data from our study provide little evidence of an increased risk for CBT with mothers' exposures to beauty products.