Exposure to phytoestrogens in the perinatal period affects androgen secretion by testicular Leydig cells in the adult rat

Genome-Wide Association Analysis of Semen Characteristics in Piétrain Boars

Since artificial insemination is common practice in pig breeding, the quality and persistence of the semen are decisive for the usability of individual boars. In the current study, genome-wide association analyses were performed to investigate the genetic variability underlying phenotypic variations in semen characteristics. These traits comprise sperm morphology and sperm motility under different temporal and thermal storage conditions, in addition to standard semen quality parameters. Two consecutive samples of the fourth and fifth ejaculates from the same boar were comprehensively analyzed in a genotyped Piétrain boar population. A total of 13 genomic regions on different chromosomes were identified that contain single-nucleotide polymorphisms significantly associated with these traits. Subsequent analysis of the genomic regions revealed candidate genes described to be involved in spermatogenesis, such as FOXL3, GPER1, PDGFA, PRKAR1B, SNRK, SUN1, and TSPO, and sperm motility, including ARRDC4, CEP78, DNAAF5, and GPER1. Some of these genes were also associated with male fertility or infertility in mammals (e.g., CEP78, GPER1). The analyses based on these laboriously determined and valuable phenotypes contribute to a better understanding of the genetic background of male fertility traits in pigs and could prospectively contribute to the improvement of sperm quality through breeding approaches.

Effects of chronic dichlorodiphenyldichloroethylene exposure on testosterone secretion and steroidogenic pathway in the male gonad

Endocrine disrupting chemicals are present in the environment and/or in consumer products. These agents have the capacity to mimic and/or antagonize endogenous hormones and thus perturb the endocrine axis. The male reproductive tract expresses steroid hormone (androgen and estrogen) receptors at high levels and is a major target for endocrine disrupting chemicals. In this study, Long-Evans male rats were exposed to dichlorodiphenyldichloroethylene, a metabolite of dichlorodiphenyltrichloroethane and a chemical present in the environment, in drinking water at 0.1 and 10 μg/L for 4 weeks. At the end of exposure, we measured steroid hormone secretion and analyzed steroidogenic proteins, including 17β-hydroxysteroid dehydrogenase, 3β-hydroxysteroid dehydrogenase, steroidogenic acute regulatory protein, aromatase, and the LH receptor. We also analyzed Leydig cell apoptosis (poly-(ADP-ribose) polymerase) and caspase-3 in the testes. Testicular testosterone (T) and 17β-estradiol (E2) were both affected by exposure to dichlorodiphenyldichloroethylene by displaying altered steroidogenic enzyme expression. Dichlorodiphenyldichloroethylene exposure also increased the expression of enzymes mediating the pathway for programmed cell death, including caspase 3, pro-caspase 3, PARP, and cleaved PARP. Altogether, the present results demonstrate that dichlorodiphenyldichloroethylene directly and/or indirectly can target specific proteins involved in steroid hormone production in the male gonad and suggest that exposure to environmentally relevant dichlorodiphenyldichloroethylene levels has implications for male reproductive development and function.

Associations between maternal urinary isoflavone concentrations and anogenital distance of offspring throughout infancy: a prospective cohort study

STUDY QUESTION

Are maternal urinary isoflavone (ISO) concentrations during pregnancy associated with anogenital distance (AGD) in infants at birth, and at 6 and 12 months of age?

SUMMARY ANSWER

Higher maternal urinary ISO concentrations during pregnancy were associated with longer AGD in infants of both sexes, and equol (EQU) and daidzein (DAD) were identified as the important ISO mixture components in the observed associations.

WHAT IS KNOWN ALREADY

Evidence of the association of prenatal exposure to ISO with offspring's AGD is mainly derived from animal studies, which used different study designs and had inconsistent results. Only one human study has been reported and it found null associations between maternal ISO exposure during pregnancy and AGD among boys at birth, with a small sample size and a wide range of exposure windows. No human study on girls was found.

STUDY DESIGN, SIZE, DURATION

Prospective cohort study (Shanghai-Minhang Birth Cohort Study), with pregnant women recruited at 12-16 weeks of gestation in Shanghai, China between April and December 2012. One thousand two hundred and twenty-five live singletons were left in the cohort at delivery of which 480 mother-infant pairs had data on both maternal urinary ISO concentrations and at least one AGD measurement and were included in the present study. Anopenile distance (AGDAP) and anoscrotal distance (AGDAS) of boys and anoclitoral distance (AGDAC) and anofourchette distance (AGDAF) of girls were measured at birth and at 6 and 12 months of age.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Multiple linear regression models were used to examine the associations between maternal ISO concentrations and AGD. Bayesian kernel machine regression (BKMR) was implemented to examine both the overall effects of ISO mixture and the single effect of each ISO and identify important components of ISO mixture.

MAIN RESULTS AND THE ROLE OF CHANCE

A general profile of higher concentrations of maternal ISO associated with longer AGD in infants of both sexes was observed, when maternal education, parity, BMI before pregnancy (BMI, categorical variable), passive smoking during early pregnancy, age at delivery, gestational weeks and infant body size were adjusted for. Among boys, EQU was associated with increased AGDAS at birth and at 6 and 12 months, and DAD was associated with increased AGDAP at birth. Among girls, the associations of EQU and DAD with increased AGDAC and AGDAF at birth were found. When gestational weight gain and feeding patterns of infants in the first 6 months were additionally adjusted for, and maternal BMI was adjusted for as a continuous variable, more pronounced associations were observed, especially for associations of genistein (GEN), DAD and glycitein (GLY) with increased AGDAP and AGDAS at 6 months in boys. However, these associations were not always observed in the highest tertile group, and no consistent dose-response relationships were found. Similar results were observed in BKMR models, showing positive correlations of concentration of ISO mixture with increased AGDAS at both 6 and 12 months among boys, and increased AGDAC and AGDAF at birth among girls. Statistically significant increments of 4.96 mm (95% credible interval (CrI): 1.40, 8.52) and 1.07 mm (95% CrI: 0.02, 2.13) in AGDAS at 6 months among boys and AGDAC at birth among girls, respectively, were observed at the 75th percentile of ISO mixture, compared with 25th percentile. EQU and DAD were identified as the important components among ISO-AGD associations.

LIMITATIONS, REASONS FOR CAUTION

First, due to the short half-lives of ISO, the accuracy of a single spot urine sample reflecting ISO exposure during pregnancy may be limited, and thus may cause non-differential misclassification. Second, despite the adjustments for several important covariates in the study, unmeasured and residual confounding factors may remain a concern. Third, false discovery due to multiple testing may remain. Finally, the reduced sample sizes attributed to the loss of follow-up and missing data of confounders may limit our ability to detect an association, if any existed.

WIDER IMPLICATIONS OF THE FINDINGS

Prenatal ISO exposure may affect the reproductive development of offspring. As ISO can be widely detected in pregnant women, especially in Eastern countries, more studies are warranted to provide evidence of the effects of prenatal ISO exposure on long-term reproductive outcomes.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by grants from the National Key Research and Development Program of China (2021YFC2701003), the National Natural Science Foundation of China (22076123), the Science and Technology Commission of Shanghai Municipality (21ZR1454700 and 20ZR1448000), the Shanghai Municipal Health Commission (20194Y0160) and Innovation-oriented Science and Technology Grant from NHC Key Laboratory of Reproduction Regulation (CX2022-04). The authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Reproductive disruption in adult female and male rats prenatally exposed to mesquite pod extract or daidzein

Phytoestrogens are considered to be endocrine disruptors, since they can alter the endocrine system, thus disturbing many reproductive events. The intake of diets containing a high content of phytoestrogens has increased worldwide in human populations and in domestic animals. Phytoestrogens in maternal blood can pass through the placenta to the fetus in high amounts and can have long-term organizational effects. Mesquite (Prosopis sp) is a leguminous plant widely used to feed several livestock species, and is also used in the human diet. In this study we assessed the effects of exposure to mesquite pod extract during the periconception and pregnancy periods on the reproduction of male and female descendants. The females of three experimental groups received one of the following treatments: 1) vehicle injection; 2) mesquite pod extract or 3) the isoflavone daidzein during the periconception and pregnancy periods. Estrous cyclicity, sexual behavior and hormones, as well as uterine and vaginal epithelia were evaluated in the female descendants. In the males, sexual behavior and hormones, apoptosis in testicular cells and sperm quality were evaluated. In females the following was observed: alterations in estrous cycles, decreased sexual behavior, estradiol and progesterone levels, increased uterine and vaginal epithelia. In males, we observed a decrease in sexual behavior, testosterone and sperm quality, and apoptosis increased in testicular cells. All these effects were similar to those caused by daidzein. These results indicate that prenatal exposure to mesquite pod extract or daidzein, administered to females before and during pregnancy, can disrupt normal organizational-activational programming of reproductive physiology in female and male descendants.

Consumption of soy isoflavones during the prepubertal phase delays puberty and causes hypergonadotropic hypogonadism with disruption of hypothalamic-pituitary gonadotropins regulation in male rats

Isoflavones are phytoestrogens with recognized estrogenic activity but may also affect testosterone, corticosterone and thyroid hormone levels in experimental models. However, the molecular mechanisms involved in these alterations are still unclear. Isoflavones are present in soy-based infant formula, in breast milk after the consumption of soy by the mother and are widely used for the preparation of beverages consumed by toddlers and teenagers. In this sense, we proposed to investigate the effects of soy isoflavone exposure during the prepubertal period, a recognized window of sensitivity for endocrine disruption, over the hypothalamic-pituitary-testicular (HPT) axis. For this, 42 3-week-old male Wistar rats were exposed to 0.5, 5 or 50 mg of soy isoflavones/kg from postnatal day (PND) 23 to PND60. We evaluated body growth, age at puberty, serum concentrations of LH, FSH, testosterone and estradiol, and the expression of the transcripts (mRNA) of genes encoding key genes controlling the hypothalamic-pituitary-testicular (HPT) axis. In the hypothalamus, we observed an increase in Esr1 mRNA expression (0.5 and 5 mg). In the pituitary, we observed an increase in Gnrhr mRNA expression (50 mg), a reduction in Lhb mRNA expression (0.5 mg), and a reduction in Ar mRNA expression. In the testis, we observed an increase in Lhcgr mRNA expression (50 mg) and a reduction in Star mRNA expression (0.5 and 5 mg). The serum levels of LH (5 and 50 mg) and FSH (0.5 mg) were increased, while testosterone and estradiol were reduced. Puberty was delayed in all groups. Taken together, these results suggest that prepubertal consumption of relevant levels of soy isoflavones disrupts the HPT axis, causing hypergonadotropic hypogonadism and altered expression levels of key genes regulating the axis.

The Fate of Leydig Cells in Men with Spermatogenic Failure

The steroidogenic cells in the testicle, Leydig cells, located in the interstitial compartment, play a vital role in male reproductive tract development, maintenance of proper spermatogenesis, and overall male reproductive function. Therefore, their dysfunction can lead to all sorts of testicular pathologies. Spermatogenesis failure, manifested as azoospermia, is often associated with defective Leydig cell activity. Spermatogenic failure is the most severe form of male infertility, caused by disorders of the testicular parenchyma or testicular hormone imbalance. This review covers current progress in knowledge on Leydig cells origin, structure, and function, and focuses on recent advances in understanding how Leydig cells contribute to the impairment of spermatogenesis.

Estrogenic Pastures: A Source of Endocrine Disruption in Sheep Reproduction

Phytoestrogens can impact on reproductive health due to their structural similarity to estradiol. Initially identified in sheep consuming estrogenic pasture, phytoestrogens are known to influence reproductive capacity in numerous species. Estrogenic pastures continue to persist in sheep production systems, yet there has been little headway in our understanding of the underlying mechanisms that link phytoestrogens with compromised reproduction in sheep. Here we review the known and postulated actions of phytoestrogens on reproduction, with particular focus on competitive binding with nuclear and non-nuclear estrogen receptors, modifications to the epigenome, and the downstream impacts on normal physiological function. The review examines the evidence that phytoestrogens cause reproductive dysfunction in both the sexes, and that outcomes depend on the developmental period when an individual is exposed to phytoestrogen.

Isoflavones alter male and female fertility in different development windows

Isoflavones are a group of secondary metabolites found in plants belonging to the class of phytoestrogens. These, because they have a chemical structure similar to the endogenous hormone 17β-estradiol, act as endocrine disruptors over the different development window periods. This study aimed to evaluate male and female reproductive systems' responses when exposed to isoflavones during the development window. It is characterized as a bibliographic review, built after analyzing clinical and preclinical articles indexed in English, Portuguese, and Spanish published in the last ten years. The isoflavones, aglycone or glucosides, have essential therapeutic properties in the relief of postmenopausal symptoms in women, reduce the proliferation of cancers, in addition to being antioxidants. On the other hand, they can still behave in a similar way to 17β-estradiol, binding to hormone receptors and acting as endocrine disruptors over the gestational period until pre-puberty, negatively affecting the development of the reproductive system. The effects on reproduction are not dose-response but are influenced by the type of isoflavone and period. There are variations in the serum concentration of hormones and action on their negative feedback on the hypothalamic-pituitary-testicular axis in males. Reproductive functions are also affected by spermatogenesis, such as decreased sperm count, lower reproductive performance, reduced litter size, low sperm production, and reduced seminal vesicle size. In females, puberty is reached later, irregular estrous cycle, reduced weight of the ovary, uterus, lower serum levels of estradiol and progesterone, reduced fertility, or interrupted fertility. At the end of the analysis of the selected publications, it can be concluded that despite the beneficial therapeutic effects in the face of pathologies, the unknown consumption of doses and types of isoflavones in food can damage the development and reproduction of individuals. Therefore, further studies must be carried out to elucidate the usual safe doses of the analyzed phytoestrogen. Greater control over insertion in foods targeted at pediatric consumers should be implemented until we have adequate safety.

Beneficiary and Adverse Effects of Phytoestrogens: A Potential Constituent of Plant-based Diet

BACKGROUND

Phytoestrogens are non-endocrine, non-steroidal secondary derivatives of plants and consumed through a plant-based diet also named as "dietary estrogens". The major sources of phytoestrogens are soy and soy-based foods, flaxseed, chickpeas, green beans, dairy products, etc. The dietary inclusion of phytoestrogen based foods plays a crucial role in the maintenance of metabolic syndrome cluster, including obesity, diabetes, blood pressure, cancer, inflammation, cardiovascular diseases, postmenopausal ailments and their complications. In recent days, phytoestrogens are the preferred molecules for hormone replacement therapy. On the other hand, they act as endocrine disruptors via estrogen receptor-mediated pathways. These effects are not restricted to adult males or females and identified even in development.

OBJECTIVE

Since phytoestrogenic occurrence is high at daily meals for most people worldwide, they focused to study for its beneficiary effects towards developing pharmaceutical drugs for treating various metabolic disorders by observing endocrine disruption.

CONCLUSION

The present review emphasizes the pros and cons of phytoestrogens on human health, which may help to direct the pharmaceutical industry to produce various phytoestrongen based drugs against various metabolic disorders.

Relevance of the Isoflavone Absorption and Testicular Function: A Systematic Review of Preclinical Evidence

Isoflavone is a phytoestrogen found in different types of food that can act as endocrine disrupters leading to testicular dysfunction. Currently, fragmented data on the action of this compound in the testicles make it difficult to assess its effects to define a safe dose. Thus, we systematically reviewed the preclinical evidence of the impact of isoflavone on testicular function. We also determined which form (aglycones or glycosylated) was the most used, which allowed us to understand the main biological processes involved in testicular function after isoflavone exposure. This systematic review was carried out according to the PRISMA guidelines using a structured search on the biomedical databases MEDLINE (PubMed), Scopus, and Web of Science, recovering and analyzing 22 original studies. The bias analysis and the quality of the studies were assessed by the criteria described in the risk of bias tool developed by SYRCLE (Systematic Review Centre for Laboratory Animal Experimentation). The aglycones and glycosylated isoflavones proved to be harmful to the reproductive health, and the glycosylates at doses of 50, 100, 146, 200, 300, 500, and 600 mg/kg, in addition to 190 and 1000 mg/L, appear to be even more harmful. The main testicular pathologies resulting from the use of isoflavones are associated with Leydig cells resulting from changes in molecular functions and cellular components. The most used isoflavone to evaluate testicular changes was the genistein/daidzein conjugate. The consumption of high doses of isoflavones promotes changes in the functioning of Leydig cells, inducing testicular changes and leading to infertility in murine models.

Different exposure windows to low doses of genistein and/or vinclozolin result in contrasted disorders of testis function and gene expression of exposed rats and their unexposed progeny

Living species including humans are continuously exposed to low levels of a myriad of endocrine active compounds that may affect their reproductive function. In contrast, experimental designs scrutinizing this question mostly consider the gestational/lactational period, select high unrealistic doses and, have rarely investigated the possible reproductive consequences in the progeny. The present study aimed at assessing comparatively a set of male reproductive endpoints according to exposure windows, gestational/lactational versus pre-pubertal to adulthood, using low doses of endocrine active substances in male rats as well as their unexposed male progeny. Animals were orally exposed to 1 mg/kg bw/d of genistein and/or vinclozolin, from conception to weaning or from prepuberty to young adulthood. A number of reproductive endpoints were assessed as well as testicular mRNA expression profiles, in the exposed rats and their unexposed progeny. Overall, the low dosage used only affected weakly most of classical reproductive endpoints. However, the gestational/lactational exposure to vinclozolin alone or combined to genistein significantly delayed the puberty onset. Contrasting with the gestational/lactational exposure, a decreased sperm production was found in the animals exposed to genistein and vinclozolin from the pre-pubertal period but also in their progeny for vinclozolin and the mixture. The expression level of several genes involved in meiosis, apoptosis and steroidogenesis was also affected differentially as a function of the exposure window in both exposed rats and unexposed offspring. We also provide further evidence that doses of endocrine active substances relevant with human exposure may affect the male reproductive phenotype and testicular transcriptome in the exposed generation as well as in the indirectly exposed offspring.

Regulation of the neuroendocrine axis in male rats by soy-based diets is independent of age and due specifically to isoflavone action†

Soy-based foods are consumed for their health beneficial effects, implying that the population is exposed to soy isoflavones in the diet. Herein, male rats at 21, 35, and 75 days of age were maintained either on a casein control diet, soybean meal (SBM), or control diet supplemented with daidzin and genistin (G + D) for 14 days. Feeding of SBM and G + D diets decreased testicular testosterone (T) secretion regardless of age. Altered androgen secretion was due to decreased (P < 0.05) Star and Hsd17β protein in the testes and was associated with increased (P < 0.05) Lhβ and Fshβ subunit protein expression in pituitary glands. Second, male rats were fed either a casein control diet, control diet + daidzin, control diet + genistin, or control diet + genistin + daidzin (G + D). Compared to control, feeding of all isoflavone-containing diets decreased (P < 0.05) testicular T concentrations, and more so in the G + D diet group. Interestingly, Esr1 and androgen receptor protein and pituitary Fshβ with Lhβ subunit protein were increased (P < 0.05) by feeding of genistin and G + D diets, but not the daidzin diet. However, daidzein and genistein both caused a concentration dependent inhibition (P < 0.05) of T secretion by Leydig cells in vitro with IC50 of 184 ηM and 36 ηM, respectively. Results demonstrated that altered testicular steroidogenic capacity and pituitary FSHβ and LHβ subunit expression due to soy-based diets result from specific actions by genistein and daidzein. Experiments to assess effects of isoflavone regulation of intratesticular androgen concentrations on male fertility are warranted.

Oral Exposure to Genistein during Conception and Lactation Period Affects the Testicular Development of Male Offspring Mice

Simple Summary

Spermatogenesis and hormones secretions are important life-threating and complicated process, which can be affected by environmental estrogens. Genistein, a type of isoflavones, widely exists in the soybean products diet, which exerts a controversial role in reproductive regulation for its special structures or functions. The results of the study revealed that low-dose genistein treatment increased the level of testosterone in the mice serum, and positively regulated expression of spermatogenesis-related genes, which enhanced spermatogenesis and testicular development. However, High-dose genistein treatment induced apoptosis of germ cells and inhibited proliferation of germ cells during spermatogenesis. Reproductive alterations in the structures and functions of testis were dose-dependent in different genistein treatments.

Abstract

Sexual hormones are essential for the process of spermatogenesis in the testis. However, the effect of maternal genistein (GEN) on the pups’ testicular development remain-unclear. Our present study evaluated the effects of supplementing GEN for parental and offspring mice on the reproductive function and growth performance of the male pups. Mothers during gestation and lactation period were assigned to a control diet (CON group), low dose GEN (LGE group) diet (control diet +40 mg/kg GEN), and high dose of GEN (HGE group) diet (control diet +800 mg/kg GEN). Their male offspring underwent the same treatment of GEN after weaning. LGE treatment (40 mg/kg GEN) significantly increased body weights (p < 0.001), testes weights (p < 0.05), diameters of seminiferous tubule (p < 0.001) and heights of seminiferous epithelium (p < 0.05) of offspring mice. LGE treatment also increased serum testosterone (T) levels and spermatogenesis scoring (p < 0.05). However, HGE treatment (800mg/kg GEN) significantly decreased body weights (p < 0.001), testes weights (p < 0.05) and testis sizes (p < 0.001). Furthermore, mRNA expressions of ESR2 (p < 0.05), CYP19A1 (p < 0.001), SOX9 (p < 0.001) and BRD7 (p < 0.001) in testis of mice were increased in the LGE group. Similarly, HGE treatment increased mRNA expressions of ESR2 (p < 0.05) and CYP19A1 (p < 0.001). However, mRNA expressions of SOX9 and BRD7 were decreased significantly in the HGE group (p < 0.001). Meanwhile, higher ratio apoptotic germ cells and abnormal sperms were detected in the HGE group (p < 0.001). In conclusion, exposure to a low dose of GEN during fetal and neonatal life could improve testicular development of offspring mice, whereas, unfavorable adverse effects were induced by a high dose of GEN.

Recovery of Prenatal Baicalein Exposure Perturbed Reproduction by Postnatal Exposure of Testosterone in Male Mice

Baicalein (BC), a flavonoid, which lacks the qualities of reproductive health and shows adverse effects, is tested in this study. Inseminated mice were injected with 30, 60, and 90 mg BC/Kg body weight on gestation days 11, 13, 15, and 17. The F1 BC-exposed males of each dosage were divided into six groups. First three groups (n = 6 from each BC dosage) were used for assessment of reproductive performance, the others (n = 4 from each BC dosage) were administered with testosterone 4.16 mg/kg body weight on postnatal days 21, 31, and 41. The reproductive health of adult F1 males at the age of 55 and 60 was tested. Prenatal BC exposure showed reduced fertility after cohabitation with control females. The BC exposure significantly reduced the body weight, tissue indices, and sperm parameters (motility, count, viability, and daily sperm count) and altered the sperm membrane in a hypoosmotic swelling test. A downward trend was observed in testicular steroidogenic marker enzymes (3β- and 17β-steroid dehydrogenases) and serum testosterone, whereas increase in serum titers of FSH and LH along with altered the testicular histology. Conversely, testosterone (4.16 mg/kg body weight) partially recovered reduced male reproductive health by BC. BC impaired male reproductive health due to low levels of testosterone is reverted by external testosterone is evidenced in this study.

Soybean isoflavone affects in rabbits: Effects on metabolism, antioxidant capacity, hormonal balance and reproductive performance

Though soybean isoflavones (SBI) have pharmaceutical properties, the compounds also have endocrine disrupting activities that may adversely affect fertility of mammals. The effects of SBI on metabolism, antioxidant capacity, hormonal balance and reproductive performance of male rabbits were investigated. Adult male rabbits (n = 21) fed an isoflavone-free diet were orally treated with 0 (control; CON), 5 (small; LSBI) or 20 (large; HSBI) mg of SBI/kg body weight/day for 12 weeks. Both SBI doses resulted in lesser blood plasma total protein concentrations, while there were no effects on glucose and cholesterol concentrations compared to CON. The HSBI-treated males had the greatest (P <  0.05) blood plasma total antioxidant capacity and least malondialdehyde. Treatment with both SBI doses induced a 43% increase in triiodothyronine concentrations (P < 0.05) and 82% in reaction times (P <  0.001), while decreased sperm concentrations (P =  0.01) and blood plasma testosterone concentrations (P =  0.017) 26% and 19%, respectively. The total functional sperm fraction was less (P <  0.05) in the HSBI group; however, there was no effect of the LSBI treatment as compared to values for the CON group. The kindling rates of females mated to HSBI-treated males tended to be less (P =  0.081) than those of does mated with LSBI or CON males. In conclusion, only the HSBI treatment improved antioxidant status; whereas, treatment with both LSBI and HSBI doses induced a hormonal imbalance which led to an impaired testis function indicating the sensitivity of the adult male reproductive system to SBI actions.

EB 2017 Article: Soy protein isolate feeding does not result in reproductive toxicity in the pre-pubertal rat testis

The isoflavone phytoestrogens found in the soy protein isolate used in soy infant formulas have been shown to have estrogenic actions in the developing male reproductive tract resulting in reproductive toxicity. However, few studies have examined potential estrogenicity of soy protein isolate as opposed to that of pure isoflavones. In this study, we fed weanling male Sprague-Dawley rats a semi-purified diet with casein or soy protein isolate as the sole protein source from postnatal day 21 to 33. Additional groups were fed casein or soy protein isolate and treated s.c. with 10 µg/kg/d estradiol via osmotic minipump. Estradiol treatment reduced testis, prostate weights, and serum androgen concentrations ( P < 0.05). Soy protein isolate had no effect. Estradiol up-regulated 489 and down-regulated 1237 testicular genes >1.5-fold ( P < 0.05). In contrast, soy protein isolate only significantly up-regulated expression of 162 genes and down-regulated 16 genes. The top 30 soy protein isolate-up-regulated genes shared 93% concordance with estradiol up-regulated genes. There was little overlap between soy protein isolate down-regulated genes and those down-regulated by estradiol treatment. Functional annotation analysis revealed significant differences in testicular biological processes affected by estradiol or soy protein isolate. Estradiol had major actions on genes involved in reproductive processes including down-regulation of testicular steroid synthesis and expression of steroid receptor activated receptor (Star) and cytochrome P450 17α-hydroxylase/(Cyp17a1). In contrast, soy protein isolate primarily affected pathways associated with macromolecule modifications including ubiquitination and histone methylation. Our results indicate that rather than acting as a weak estrogen in the developing testis, soy protein isolate appears to act as a selective estrogen receptor modulator with little effect on reproductive processes. Impact statement Soy protein isolate (SPI) is the sole protein used to make soy-based infant formulas. SPI contains phytoestrogens, which are structurally similar to estradiol. These phytoestrogens, daidzein, genistein, and equol, fit the definition of endocrine-disrupting compounds, and at high concentrations, have estrogenic actions resulting in reproductive toxicity in the developing male, when provided as isolated chemicals. However, few animal studies have examined the potential estrogenicity of SPI as opposed to pure isoflavones. In this study, SPI feeding did not elicit an estrogenic response in the testis nor any adverse outcomes including reduced testicular growth, or androgen production during early development in rats when compared to those receiving estradiol. These findings are consistent with emerging data showing no differences in reproductive development in males and female children that received breast milk, cow's milk formula, or soy infant formula during the postnatal feeding period.

Adverse Effects of Nutraceuticals and Dietary Supplements

Over 70% of Americans take some form of dietary supplement every day, and the supplement industry is currently big business, with a gross of over $28 billion. However, unlike either foods or drugs, supplements do not need to be registered or approved by the US Food and Drug Administration (FDA) prior to production or sales. Under the Dietary Supplement Health and Education Act of 1994, the FDA is restricted to adverse report monitoring postmarketing. Despite widespread consumption, there is limited evidence of health benefits related to nutraceutical or supplement use in well-nourished adults. In contrast, a small number of these products have the potential to produce significant toxicity. In addition, patients often do not disclose supplement use to their physicians. Therefore, the risk of adverse drug-supplement interactions is significant. An overview of the major supplement and nutraceutical classes is presented here, together with known toxic effects and the potential for drug interactions.

Influence of prolonged flaxseed ( Linum usitatissimum ) consumption over epididymis and testicle histoarchitecture of Wistar rats

ABSTRACT: Flaxseed is considered a functional food with several health benefits. However, because of its high phytoestrogen content, flaxseed influences hormone metabolism and affects the gonadal biomorphology. In this study, computerized histomorphometry was used to evaluate seminiferous and epididymal tubules, considering the different regions of the epididymis (head, body and tail) of rats subjected to a prolonged diet of flaxseed. Young adult male Wistar rats (n=20) were divided into 2 groups during their lactation period: Control Group (CG), fed casein-based meals and Flaxseed Group (FG), fed a 25% flaxseed meal. After 250 days of continuous ingestion, the animals were euthanized and a blood sample was collected. The testicles and epididymis were removed and fixed in buffered formalin solution. The samples were subjected to routine histological paraffin techniques and stained with hematoxilin and eosin. Immunostaining was performed using an antivimentin antibody for Sertoli cell identification. For morphometry, images of the slides were scanned and analyzed using Image J to determine the epithelial height, tubular and luminal diameter and tubular and luminal area. In the hormonal evaluation, FG had a higher serum concentration of estrogen (P=0.001), but no change was observed in the concentration of testosterone. The morphometric assay of seminiferous tubules and epididymal regions revealed no significant differences between the analyzed groups. Similarly, Sertoli cell quantification showed no significant differences in the FG (P=0.98). These results revealed that the continuous and prolonged intake of 25% flaxseed meals from gestation to 250 days of age, even with a significant increase in serum levels of estradiol, does not exert adverse effects on the testicular and epididymal structure or on the cells participating in the spermatogenesis of rats.

Feasibility, phase I, and phase II studies of tandutinib, an oral platelet-derived growth factor receptor-β tyrosine kinase inhibitor, in patients with recurrent glioblastoma

Background

Platelet-derived growth factor (PDGF) signaling is important in gliomagenesis and PDGF receptor-β is expressed on most endothelial cells in glioblastoma specimens.

Methods

We report the results of feasibility, phase I, and phase II studies of tandutinib (MLN518), an orally bioavailable inhibitor of type III receptor tyrosine kinases including PDGF receptor-β, Fms-like tyrosine kinase 3, and c-Kit in patients with recurrent glioblastoma.

Results

In an initial feasibility study, 6 patients underwent resection for recurrent glioblastoma after receiving tandutinib 500mg twice daily for 7 days. The mean ratio of tandutinib concentration in brain tumor-to-plasma was 13.1±8.9 in 4 of the 6 patients. In the phase I study, 19 patients were treated at 500, 600, and 700mg twice daily dose levels. The maximum tolerated dose was found to be 600mg twice daily, and 30 patients were treated with this dose in the phase II study. The trial was closed after interim analysis, as the prespecified goal of patients alive and progression-free survival at 6 months was not achieved. Biomarker studies suggested that tandutinib treatment could lead to vascular disruption rather than normalization, which was associated with rapid progression.

Conclusions

Tandutinib readily distributed into the brain following oral administration and achieved concentrations within the tumor that exceed the corresponding concentration in plasma. The phase II study was closed at interim analysis due to lack of efficacy, although this study was not enriched for glioblastomas with alterations of the PDGF pathway.

Effects of daidzein on testosterone secretion in cultured immature mouse testis

Background: Daidzein is a major isoflavone in soybeans. Several in vivo studies have showed that daidzein can affect immature male testosterone production. However, whether daidzein has direct action on immature male testis is unknown.

Objective: We investigated the effects of daidzein on testosterone secretion in 3-day-old and 21-day-old mouse Leydig cells with organotypic culture model.

Materials and Methods: The testes were exposed to different concentrations (10-7 to 10-4 M) of daidzein for 72 h with medium changed every 24 h. From 72 to 75 h of culture, 100 ng/ml human chorionic gonadotropin (hCG) was added. The testosterone production was determined, and the related mechanisms of daidzein action were also evaluated by measuring the mRNA levels of steroidogenic acute regulatory protein (StAR), cholesterol side-chain cleavage enzyme (P450scc), and 3β-hydroxysteroid dehydrogenase (3β-HSD-1) involved in testosterone biosynthesis.

Results: The results revealed that in the presence of 100 ng/ml hCG, 10-7 to 10-5 M daidzein had no significant effect on testosterone secretion in cultured 3-day-old mouse testis. But 10-4 M daidzein significantly increased testosterone concentration (p < 0.05). Daidzein in range of studied doses had no obvious influence on testosterone production in cultured 21-day-old mouse testis. RT-PCR results showed that 10-4 M daidzein had obvious influence on the mRNA levels of StAR, P450scc and 3β-HSD-1 in cultured 3-day-old mouse testis (p < 0.05).

Conclusion: These results suggest that daidzein mainly influences neonatal mouse testis function, and the influence is partially related to the upregulation of StAR, P450scc, and 3β-HSD-1 mRNA levels.

Effects of dietary soybean isoflavones (SI) on reproduction in the young breeder rooster

Soybean isoflavones (SIs) are phytoestrogens that competitive with estrogens in body. Although SIs play an important role in reproduction, their role in testicular development in roosters is unknown. This study was conducted to investigate the effect of SIs on testicular development and serum reproductive hormone profiles in young breeder roosters (70-133days old). Gene expression of steroidogenic acute regulatory protein (StAR), cholesterol side-chain cleavage enzyme (P450scc), and 3β-hydroxysteroid dehydrogenase (3β-HSD), which are related to testosterone synthesis, in rooster testis were also evaluated after treatment with different SI doses. Although SIs had no significant effect on body weight, 5mg/kg SIs significantly increased the testis index and serum levels of reproductive hormones (gonadotropin releasing hormone, follicle- stimulating hormone, luteinizing hormone, and testosterone).To further investigate whether SIs regulate hormone synthesis via StAR, p450scc, 3β-HSD, real time-PCR was performed to measure the mRNA levels of the corresponding genes. The results showed that 5mg/kg of SIs significantly increased StAR mRNA levels. However, there were no significant effects on p450scc or 3β-HSD mRNA levels. Moreover, the spermatogonial development and the number of germ cell layers were increased by treatment with 5mg/kg of SIs. These results suggest that SIs promote testicular growth by increasing reproductive hormone secretion, which is closely related to StAR expression, to positively regulate reproduction in young roosters.

Altered spermatogenesis, steroidogenesis and suppressed fertility in adult male rats exposed to genistein, a non-steroidal phytoestrogen during embryonic development

This article focuses on the effects of prenatal exposure to genistein on the mother, her pregnancy and reproductive functions of the male progeny, since these issues have ethological relevance in both animals and humans. Pregnant Wistar rats received i.p. injections of genistein at a dose level of 2, 20 or 100 mg/kg body weight daily from 12^th to 19^th day of gestation. Male pups from control and genistein exposed animals were weaned and allowed to develop until 100 days of age; however, when they were 90 days old, twelve males from each group were cohabited with untreated 90-day old females for 8 days. Results revealed a significant decrease in indices of reproductive organs in adult male rats exposed to genistein during embryonic development. Dose dependent reduction was observed in daily sperm production and epididymal sperm density and quality in genistein treated rats. Significant decrease was observed in the activity levels of 3β- and 17β-hydroxysteroid dehydrogenases in testis of experimental rats with a decline in plasma testosterone levels. Histological examination of testis of genistein treated rats indicated deterioration in testicular architecture. In the fertility study, the mean number of implantations and live fetuses per dam mated with 100 mg genistein exposed males was reduced.

Daidzein impairs Leydig cell testosterone production and Sertoli cell function in neonatal mouse testes: An in vitro study

Isoflavone is a type of phytoestrogen that exists in soy‑based products. Previous studies have reported that certain foods containing isoflavones, particularly infant formula, may have potential adverse effects on male reproductive function. However, few studies have focused on the effects of isoflavones on testosterone biosynthesis and Sertoli cell function during the neonatal period. The aim of the present study was to investigate the influence of daidzein, a common isoflavone, on testosterone secretion and Sertoli cell function during the neonatal period. The organ culture method was used to assess the effects of daidzein on neonatal mouse testes. Cultured testes were treated with daidzein (0, 0.03, 0.3, 3 or 30 µmol/l) for 72 h. To verify the mechanism of action of daidzein on androgen production, Leydig cells were also treated with daidzein for 24 h. As anticipated, testosterone secretions were suppressed by daidzein (30 µmol/l) in cultured testes and Leydig cells. Further analysis demonstrated that the expression levels of steroidogenic acute regulatory protein (StAR), cholesterol side‑chain cleavage enzyme (P450scc) and 3β‑hydroxysteroid dehydrogenase (3β‑HSD), which are transport proteins and key enzymes in androgen biosynthesis, were suppressed in cultured neonatal mouse testes. In addition, the expression levels of StAR, P450scc, 3β‑HSD and 17α‑hydroxylase/20‑lyase were decreased in Leydig cells. Notably, proliferation of Sertoli cells was also inhibited by daidzein (30 µmol/l). Furthermore, the expression levels of vimentin were significantly suppressed in the testes following treatment with daidzein, whereas inhibin B expression exhibited no change. In conclusion, daidzein may suppress steroidogenic capability and impair Sertoli cell function in the neonatal period in vitro.

Comparison of the effects of mesquite pod and Leucaena extracts with phytoestrogens on the reproductive physiology and sexual behavior in the male rat

Mesquite (Prosopis sp.) and Leucaena leucocephala are widespread legumes, widely used to feed several livestock species and as food source for human populations in several countries. Both mesquite and Leucaena contain several phytoestrogens which might have potential estrogenic effects. Thus, the aim of this study was to evaluate the effects of mesquite pod and Leucaena extracts on several aspects of behavior and reproductive physiology of the male rat. The effects of the extracts were compared with those of estradiol (E2) and of two isoflavones: daidzein (DAI) and genistein (GEN). The following treatments were given to groups of intact male rats: vehicle; mesquite pod extract; Leucaena extract; E2; DAI; GEN. The results indicate that mesquite pod and Leucaena extracts disrupt male sexual behavior in a similar way to DAI and GEN, but less than E2. The main disruptor of sexual behavior was E2, however after 40 and 50days of administration, both extracts and phytoestrogens disrupted sexual behavior in a similar way to E2. The extracts also increased testicular germ cell apoptosis, decreased sperm quality, testicular weight, and testosterone levels, as phytoestrogens did, although these effects were less than those caused by estradiol. The number of seminiferous tubules with TUNEL-positive germ cells increased in extracts treated groups in a similar way to phytoestrogens groups, and E2 caused the greatest effect. The number of TUNEL-positive cells per tubule increased only in Leucaena extract and E2 groups, but not in mesquite- and phytoestrogens-treated groups. Spermatocytes and round spermatids were the TUNEL-positive cells observed in all experimental groups. This effect was associated with smaller testicular weights without atrophy in experimental groups compared with control. Testicular atrophy was only observed in estradiol-treated males. Testosterone decreased in males of all experimental groups, compared with control, this androgen was undetectable in E2 treated males. These results suggest that mesquite pod and Leucaena extracts cause effects similar to those of phytoestrogens in male rat reproduction, these effects were lower than those caused by E2.

Differential effects of habitual chow-based and semi-purified diets on lipid metabolism in lactating rats and their offspring

Diet during pregnancy and lactation is a critical factor in relation to the health of dams and their offspring. Currently, control diets used in metabolic imprinting studies differ in composition and type, i.e. semi-purified diets (SD) or chow-based diets (ND). The aim of the present study was to determine whether two widely used control diets, a SD and a ND, that mainly differ in fat content (5·08 and 3·26 %, respectively) and its sources (soyabean oil for the SD and cereals and fish for the ND), fibre (6 and 15 %, respectively), and cholesterol (26 and 69 mg/kg diet, respectively) can influence the lipid metabolism of dams and their offspring. Wistar rats were fed either the SD or the ND during pregnancy and lactation. At weaning, SD-fed dams presented severe hepatic steatosis and increased levels of circulating TAG, NEFA and insulin. Importantly, the offspring presented an altered plasma lipid profile. In contrast, the ND allowed for a normal gestation and lactation process, and did not affect the metabolism of offspring. In parallel, virgin rats fed the SD showed no metabolic alterations. A higher intake of SFA and MUFA and a lower consumption of PUFA observed in SD-fed dams during the lactation period could contribute to explaining the observed effects. In conclusion, two different control diets produced very different outcomes in the lipid metabolism of lactating rats and their offspring. The present results highlight the importance of the assessment of the metabolic state of dams when interpreting the results of metabolic programming studies.

Isoflavones and their effects on the onset of puberty in male Wistar rats

This study was performed to determine how two of the most important isoflavones, genistein and daidzein, affect the gonadal axis in male prepuberal rats. One hundred and seventy-five prepuberal male Wistar rats were allocated into seven groups: one control group and six experimental groups that were orally administered a high or low dose of genistein, daidzein or a mixture of both. Testosterone determination was assayed by EIA. The testes and body weights were measured, and the histology of the epididymis with the sperm content and epididymal sperm count were evaluated. In the control group, we observed an increase in the serum testosterone levels (>2.5 ng ml(-1) ) at the third week (52 days), which corresponded to the onset of puberty in these rats. The same increase in serum testosterone levels was observed at the fourth week in rats that received low doses of isoflavones; therefore, we concluded that the onset of puberty was delayed. At high doses, there was no significant increase in testosterone levels, which could be related to the fact that these male rats did not reach puberty. These findings were supported by the results obtained from the analysis of the epididymal content as well as the testes/body weight ratio.

Ameliorating effect of olive oil on fertility of male rats fed on genetically modified soya bean

BACKGROUND

Genetically modified soya bean (GMSB) is a commercialized food. It has been shown to have adverse effects on fertility in animal trials. Extra virgin olive oil (EVOO) has many beneficial effects including anti-oxidant properties. The aim of this study is to elucidate if addition of EVOO ameliorates the adverse effects on reproductive organs of rats fed on GMSB containing diet.

METHODS

Forty adult male albino rats (150-180 g) of Sprague Dawley strain were separated into four groups of 10 rats each: Group 1 - control group fed on basal ration, Group 2 - fed on basal ration mixed with EVOO (30%), Group 3 - fed on basal ration mixed with GMSB (15%), and Group 4 - fed on basal ration mixed with GMSB (15%) and EVOO (30%). This feeding regimen was administered for 65 days. Blood samples were collected to analyze serum zinc, vitamin E, and testosterone levels. Histopathological and weight changes in sex organs were evaluated.

RESULTS

GMSB diet reduced weight of testis (0.66±0.06 vs. 1.7±0.06, p<0.001), epididymis (0.489±0.03 vs. 0.7±0.03, p<0.001), prostate (0.04±0.009 vs. 0.68±0.04, p<0.001), and seminal vesicles (0.057±0.01 vs. 0.8±0.04, p<0.001). GMSB diet adversely affected sperm count (406±7.1 vs. 610±7.8, p<0.001), motility (p<0.001), and abnormality (p<0.001). GMSB diet also reduced serum zinc (p<0.05), vitamin E (p<0.05), and testosterone (p<0.05) concentrations. EVOO diet had no detrimental effect. Addition of EVOO to GMSB diet increased the serum zinc (p<0.05), vitamin E (p<0.05), and testosterone (p<0.05) levels and also restored the weights of testis (1.35±0.16 vs. 0.66±0.06, p<0.01), epididymis (0.614±0.13 vs. 0.489±0.03, p<0.001), prostate (0.291±0.09 vs. 0.04±0.009, p<0.001), seminal vesicle (0.516±0.18 vs. 0.057±0.01, p<0.001) along with sperm count (516±3.1 vs. 406±7.1, p<0.01), motility (p<0.01), and abnormality (p<0.05).

CONCLUSION

EVOO ameliorates the adverse effects of GMSB on reproductive organs in adult male albino rats. This protective action of EVOO justifies its use against the oxidative damage induced by GMSB in reproductive organs.

Testicular development in male rats is sensitive to a soy-based diet in the neonatal period

Approximately 30% of infants in the United States are exposed to high doses of isoflavones resulting from soy infant formula consumption. Soybeans contain the isoflavones genistin and daidzin, which are hydrolyzed in the gastrointestinal tract to their genistein and daidzein aglycones. Both aglycones possess hormonal activity and may interfere with male reproductive development. Testosterone, which supports male fertility, is mainly produced by testicular Leydig cells. Our previous studies indicated that perinatal exposure of male rats to isoflavones induced proliferative activity in Leydig cells and increased testosterone concentrations into adulthood. However, the relevance of the neonatal period as part of the perinatal window of isoflavone exposure remains to be established. The present study examined the effects of exposure to isoflavones on male offspring of dams maintained on a casein-based control or whole soybean diet in the neonatal period, that is, Days 2 to 21 postpartum. The results showed that the soybean diet stimulated proliferative activity in developing Leydig cells while suppressing their steroidogenic capacity in adulthood. In addition, isoflavone exposure decreased production of anti-Müllerian hormone by Sertoli cells. Similar to our previous in vitro studies of genistein action in Leydig cells, daidzein induced proliferation and interfered with signaling pathways to suppress steroidogenic activity. Overall, the data showed that the neonatal period is a sensitive window of exposure to isoflavones and support the view that both genistein and daidzein are responsible for biological effects associated with soy-based diets.

Zearalenone inhibits testosterone biosynthesis in mouse Leydig cells via the crosstalk of estrogen receptor signaling and orphan nuclear receptor Nur77 expression

Zearalenone (ZEA) directly inhibits testosterone biosynthesis in Leydig cells, although the mechanisms involved remains unclear. Various experiments were performed to elucidate the molecular pathway of ZEA-mediated androgen inhibition. Leydig cells were isolated from 6 week-old male ICR mice and subjected to ZEA pre-treatment. The levels of testosterone and a series of influncing factors were measured. The results showed that ZEA caused a concentration- and time-dependent inhibition of testosterone stimulated both by hCG and cAMP (P<0.05). Exposure to ZEA did not affect the LHR binding activity nor the protein expression (P>0.05). However, ZEA exposure significantly elevated the cellular cAMP levels (P<0.05) in low concentrations (5 μg/ml) or for long time periods (24 h), significantly reduce the mitochondrial membrane potential (P<0.05). The expression of P450scc, 17β-HSD, and P450c17 at the mRNA level were significantly decreased (P<0.05). The steroidogenic acute regulatory (StAR) and 3β-HSD expression was significantly increased (P<0.05). Furthermore, the ERα protein expression was not affected by ZEA, but Nur77 expression was significantly inhibited (P<0.05). These observations imply that ZEA activity interferes with testosterone biosynthesis in mouse Leydig cells via the crosstalk of estrogen receptor signaling and Nur77 expression.

Mouse leydig cells with different androgen production potential are resistant to estrogenic stimuli but responsive to bisphenol a which attenuates testosterone metabolism

It is well known that estrogens and estrogen-like endocrine disruptors can suppress steroidogenic gene expression, attenuate androgen production and decrease differentiation of adult Leydig cell lineage. However, there is no information about the possible link between the potency of Leydig cells to produce androgens and their sensitivity to estrogenic stimuli. Thus, the present study explored the relationship between androgen production potential of Leydig cells and their responsiveness to estrogenic compounds. To investigate this relationship we selected mouse genotypes contrasting in sex hormone levels and differing in testosterone/estradiol (T/E₂) ratio. We found that two mouse genotypes, CBA/Lac and C57BL/6j have the highest and the lowest serum T/E₂ ratio associated with increased serum LH level in C57BL/6j compared to CBA/Lac. Analysis of steroidogenic gene expression demonstrated significant upregulation of Cyp19 gene expression but coordinated suppression of LHR, StAR, 3βHSDI and Cyp17a1 in Leydig cells from C57BL/6j that was associated with attenuated androgen production in basal and hCG-stimulated conditions compared to CBA/Lac mice. These genotype-dependent differences in steroidogenesis were not linked to changes in the expression of estrogen receptors ERα and Gpr30, while ERβ expression was attenuated in Leydig cells from C57BL/6j compared to CBA/Lac. No effects of estrogenic agonists on steroidogenesis in Leydig cells from both genotypes were found. In contrast, xenoestrogen bisphenol A significantly potentiated hCG-activated androgen production by Leydig cells from C57BL/6j and CBA/Lac mice by suppressing conversion of testosterone into corresponding metabolite 5α-androstane-3α,17β-diol. All together our data indicate that developing mouse Leydig cells with different androgen production potential are resistant to estrogenic stimuli, while xenoestrogen BPA facilitates hCG-induced steroidogenesis in mouse Leydig cells via attenuation of testosterone metabolism. This cellular event can cause premature maturation of Leydig cells that may create abnormal intratesticular paracrine milieu and disturb proper development of germ cells.

Effect of genistein administration on the recovery of spermatogenesis in the busulfan-treated rat testis

Objective

Impairment of spermatogenesis has been identified as an inevitable side effect of cancer treatment. Although estrogen treatment stimulates spermatogenic recovery from the impaired spermatogenesis by suppressing the intra-testicular testosterone (ITT) level, side effects of estrogen are still major impediments to its clinical application in humans. Soybeans are rich in genistein, which is a phytoestrogen that binds to estrogen receptors and has an estrogenic effect. We investigated the effects of genistein administration on ITT levels, testis weight, and recovery of spermatogenesis in rats treated with a chemotherapeutic agent, busulfan.

Methods

Busulfan was administered intraperitoneally to rats, and then a GnRH agonist was injected subcutaneously into the back, or genistein was administered orally.

Results

The weight of the testes was significantly reduced by the treatment with busulfan. The testis weight was partially restored after busulfan treatment by additional treatment with either the GnRH agonist or genistein. Busulfan also induced atrophy of a high percentage of the seminiferous tubules, but this percentage was decreased by additional treatment with either the GnRH agonist or genistein. Treatment with genistein was effective at suppressing and maintaining ITT levels comparable to that in the GnRH agonist group.

Conclusion

Genistein effectively suppressed ITT levels and stimulated the recovery of spermatogenesis in rats treated with a chemotherapeutic drug. This suggests that genistein may be a substitute for estrogens, for helping humans to recover fertility after cancer therapy without the risk of side effects.

Endocrine disrupting effects in rats perinatally exposed to a dietary relevant mixture of phytoestrogens

Dietary phytoestrogens may prevent certain human diseases, but endocrine activity has been reported in animal studies. Sprague-Dawley rats were exposed perinatally to a 1-, 10- or 100-fold "high human dietary intake" mixture of 12 phytoestrogens consisting of mainly the lignan secoisolarici resinol and the isoflavones genistein and daidzein. This mixture induced persistent adverse effects, as adult male mammary glands showed hypertrophic growth. A reduced anogenital distance in newborn males indicated an anti-androgenic mode of action. Testosterone levels, testis and prostate weights, and expression of selected genes in testis and prostate were unaffected. Decreased serum estradiol was seen in genistein-exposed dams. This study indicated adverse effects at high intake levels in rats, but does not provide evidence for risk of phytoestrogen-mediated endocrine disruption at normal human dietary consumption levels. Further studies are warranted to increase the knowledge upon which risk assessment on dietary phytoestrogen exposure during pregnancy and infancy is based.

Male rat hormone imbalance, testicular changes and toxicity associated with aqueous leaf extract of an antimalarial plant: Phyllanthus niruri

CONTEXT

Phyllanthus niruri L. (Euphorbiaceae), a medicinal plant traditionally known for dissolving kidney stones, is used prophylactically as an antimalarial agent.

OBJECTIVE

The study was undertaken to determine its effect on some male hormones and other toxicological properties due to paucity of its data despite its wide use.

MATERIAL AND METHODS

Male Sprague-Dawley rats (100-140 g) were used. Group 1 [control group (C), n = 6] received water. Group 2 [low-dose test group (LD), n = 6] received 50 mg/kg body weight (b.wt.) aqueous leaf extract orally. Group 3 [high-dose test group (HD), n = 6] received 500 mg/kg b.wt. extract for 90 days. Upon sacrifice, among other organs the testes were harvested. Blood samples drawn were used for biochemical (including progesterone, estrogen and testosterone), cytotoxicity and hematological assays.

RESULTS

C, LD and HD estrogen values were 192 ± 25, 385 ± 122 and 962 ± 357 pg/ml, respectively. In the same order, progesterone values were 96 ± 24, 155 ± 45 and 320 ± 80 pg/ml, respectively. Testosterone levels were 5210 ± 1090, 4710 ± 220 and 4500 ± 580 pg/ml, respectively. Significant differences were observed in the estrogen and progesterone levels (p = 0.001). Degenerative changes were observed histologically. Cytotoxicity at 50% (CC50) was 10.0 µg/ml.

DISCUSSION AND CONCLUSION

This antimalarial plant is mildly cytotoxic with male antifertility properties.

Altered infant feeding patterns in boys with acquired nonsyndromic cryptorchidism

BACKGROUND

Genetic and environmental factors likely influence susceptibility to nonsyndromic cryptorchidism, a common disease presenting at birth or in later childhood. We compared cases and controls to define differential risk factors for congenital versus acquired cryptorchidism.

METHODS

We compared questionnaire and clinical data from cases of congenital cryptorchidism (n = 230), acquired cryptorchidism (n = 182) and hernia/hydrocele (n = 104) with a group of healthy male controls (n = 358). Potential predictor variables (p < 0.2 in univariable analysis) were included in stepwise multivariable logistic regression models.

RESULTS

Temporary (odds ratio [OR], 0.5; 95% confidence interval [CI], 0.4-0.8) or exclusive (OR, 0.6; 95% CI, 0.4-0.9) breastfeeding was reduced and soy formula feeding increased (OR, 1.8; 95% CI, 1.2-2.9) in acquired but not congenital or hernia/hydrocele groups. The highest risk estimates were observed for primary soy formula feeding with limited or no breastfeeding (OR 2.5; 95% CI, 1.4-4.3; adjusted OR, 2.7; 95% CI, 1.4-5.4) in the acquired group. Primary feeding risk estimates were equivalent or strengthened when multivariable models were limited to age greater than 2 years, full-term or not small for gestational age, or Caucasian subjects. Pregnancy complications and increased maternal exposure to cosmetic or household chemicals were not consistently associated with either form of cryptorchidism in these models.

CONCLUSIONS

Our data support reduced breastfeeding and soy formula feeding as potential risk factors for acquired cryptorchidism. Although additional studies are needed, hormonally active components of breast milk and soy formula could influence the establishment of normal testis position in the first months of life, leading to apparent ascent of testes in childhood. Birth Defects Research (Part A), 2012.

Histological and hormonal testicular function in oligo/azoospermic infertile men

We characterised and correlated the histological and hormonal aspects of a cohort of 261 azo/oligozoospermic men, applying a quantitative/qualitative evaluation of testicular tissue and serum and intratesticular hormonal measurements. One hundred and 93 azo⁄oligozoospermic patients were diagnosed as: complete sertoli cell only syndrome (cSCOS), n = 76; focal SCOS, n = 31; maturation arrest, n = 34; hypospermatogenesis, n = 17; mixed atrophy, n = 25; and severe atrophy, n = 10. Normal spermatogenesis was observed in 68 infertile men (controls). Patients with cSCOS, focal SCOS, mixed and severe atrophy had larger LC/clusters (11.5; 11.0; 10.7; 18.9 LC/cluster) than controls (6 LC/cluster; P < 0.001). cSCOS, focal SCOS, mixed and severe atrophy patients had higher FSH, LH and lower T/LH ratio serum levels than the other groups. Intratesticular testosterone concentrations were higher in tissues with complete or focal SCOS (45.6 ng mg(-1) protein) and mixed atrophy (79.0 ng mg(-1) protein) than normal tissues (20.3 ng mg(-1) protein; P = 0.03 and P = 0.007). Considering all subjects, significant correlations were found between T/LH ratio and Leydig cells/cluster (r = 0.510, P < 0.001), FSH levels (r = -0.692, P < 0.001) and with intratesticular testosterone (r = -0.354, P = 0.001); these correlations follow the pattern of severity of spermatogenic damage. By a thorough histological evaluation, we validate the concept that the severity of spermatogenic impairment is associated with major morphological and functional disturbance of the Leydig cell compartment.

Regulation of adiponectin secretion by soy isoflavones has implication for endocrine function of the testis

Testicular Leydig cells are the predominant source of the male sex steroid hormone testosterone (T), which is required to maintain male fertility. There is now growing evidence that environmental stressors, including chemicals present in food, air and water, may affect energy balance. A relationship between energy balance and reproductive capacity has been proposed for a long time. In the present study, developmental exposures of male rats to soy isoflavones in the maternal diet from gestational day 12 to day 21 post-partum enhanced adiponectin expression in adipose tissue and increased serum adiponectin concentrations in adulthood. However, exposure to soy isoflavones caused a decrease in T production and expression of adiponectin and its receptor (adipoR2) in Leydig cells. In separate experiments, incubation of Leydig cells with recombinant adiponectin in the absence of isoflavones caused a decrease in T biosynthesis associated with diminished expression of the cholesterol transporter steroidogenic acute regulatory protein (StAR). Thus, chemical-induced alterations in serum adiponectin concentrations have implication for steroid hormone secretion. The results also imply that changes in adipose tissue metabolism occasioned by exposure to dietary estrogens, and perhaps other estrogenic agents, possibly contribute to deficiencies in reproductive capacity attributed to these compounds.

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.

Inhibitors of testosterone biosynthetic and metabolic activation enzymes

The Leydig cells of the testis have the capacity to biosynthesize testosterone from cholesterol. Testosterone and its metabolically activated product dihydrotestosterone are critical for the development of male reproductive system and spermatogenesis. At least four steroidogenic enzymes are involved in testosterone biosynthesis: Cholesterol side chain cleavage enzyme (CYP11A1) for the conversion of cholesterol into pregnenolone within the mitochondria, 3β-hydroxysteroid dehydrogenase (HSD3B), for the conversion of pregnenolone into progesterone, 17α-hydroxylase/17,20-lyase (CYP17A1) for the conversion of progesterone into androstenedione and 17β-hydroxysteroid dehydrogenase (HSD17B3) for the formation of testosterone from androstenedione. Testosterone is also metabolically activated into more potent androgen dihydrotestosterone by two isoforms 5α-reductase 1 (SRD5A1) and 2 (SRD5A2) in Leydig cells and peripheral tissues. Many endocrine disruptors act as antiandrogens via directly inhibiting one or more enzymes for testosterone biosynthesis and metabolic activation. These chemicals include industrial materials (perfluoroalkyl compounds, phthalates, bisphenol A and benzophenone) and pesticides/biocides (methoxychlor, organotins, 1,2-dibromo-3-chloropropane and prochloraz) and plant constituents (genistein and gossypol). This paper reviews these endocrine disruptors targeting steroidogenic enzymes.

NTP-CERHR expert panel report on the developmental toxicity of soy infant formula

Soy infant formula contains soy protein isolates and is fed to infants as a supplement to or replacement for human milk or cow milk. Soy protein isolates contains estrogenic isoflavones (phytoestrogens) that occur naturally in some legumes, especially soybeans. Phytoestrogens are nonsteroidal, estrogenic compounds. In plants, nearly all phytoestrogens are bound to sugar molecules and these phytoestrogen-sugar complexes are not generally considered hormonally active. Phytoestrogens are found in many food products in addition to soy infant formula, especially soy-based foods such as tofu, soy milk, and in some over-the-counter dietary supplements. Soy infant formula was selected for National Toxicology Program (NTP) evaluation because of (1) the availability of large number of developmental toxicity studies in laboratory animals exposed to the isoflavones found in soy infant formula (namely, genistein) or other soy products, as well as few studies on human infants fed soy infant formula, (2) the availability of information on exposures in infants fed soy infant formula, and (3) public concern for effects on infant or child development. On October 2, 2008 (73 FR 57360), the NTP Center for the Evaluation of Risks to Human Reproduction (CERHR) announced its intention to conduct an updated review of soy infant formula to complete a previous evaluation that was initiated in 2005. Both the current and previous evaluations relied on expert panels to assist the NTP in developing its conclusions on the potential developmental effects associated with the use of soy infant formula, presented in the NTP Brief on Soy Infant Formula. The initial expert panel met on March 15 to 17, 2006, to reach conclusions on the potential developmental and reproductive toxicities of soy infant formula and its predominant isoflavone constituent genistein. The expert panel reports were released for public comment on May 5, 2006 (71 FR 28368). On November 8, 2006 (71 FR 65537), CERHR staff released draft NTP Briefs on Genistein and Soy Formula that provided the NTP's interpretation of the potential for genistein and soy infant formula to cause adverse reproductive and/or developmental effects in exposed humans. However, CERHR did not complete these evaluations, finalize the briefs, or issue NTP Monographs on these substances based on this initial evaluation. Between 2006 and 2009, a substantial number of new publications related to human exposure or reproductive and/or developmental toxicity were published for these substances. Thus, CERHR determined that updated evaluations of genistein and soy infant formula were needed. However, the current evaluation focuses only on soy infant formula and the potential developmental toxicity of its major isoflavone components, e.g. genistein, daidzein (and estrogenic metabolite, equol), and glycitein. This updated evaluation does not include an assessment on the potential reproductive toxicity of genistein following exposures during adulthood as was carried out in the 2006 evaluation. CERHR narrowed the scope of the evaluation because the assessment of reproductive effects of genistein following exposure to adults was not considered relevant to the consideration of soy infant formula use in infants during the 2006 evaluation. To obtain updated information about soy infant formula for the CERHR evaluation, the PubMed (Medline) database was searched from February 2006 to August 2009 with genistein/genistin, daidzein/daidzin, glycitein/glycitin, equol, soy, and other relevant keywords. References were also identified from the bibliographies of published literature. The updated expert panel report represents the efforts of a 14-member panel of government and nongovernment scientists, and was prepared with assistance from NTP staff. The finalized report, released on January 15, 2010 (75 FR 2545), reflects consideration of public comments received on a draft report that was released on October 19, 2009, for public comment and discussions that occurred at a public meeting of the expert panel held December 16 to 18, 2009 (74 FR 53509). The finalized report presents conclusions on (1) the strength of scientific evidence that soy infant formula or its isoflavone constituents are developmental toxicants based on data from in vitro, animal, or human studies; (2) the extent of exposures in infants fed soy infant formula; (3) the assessment of the scientific evidence that adverse developmental health effects may be associated with such exposures; and (4) knowledge gaps that will help establish research and testing priorities to reduce uncertainties and increase confidence in future evaluations. The Expert Panel expressed minimal concern for adverse developmental effects in infants fed soy infant formula. This level of concern represents a "2" on the five-level scale of concern used by the NTP that ranges from negligible concern ("1") to serious concern ("5"). The Expert Panel Report on Soy Infant Formula was considered extensively by NTP staff in preparing the 2010 NTP Brief on Soy Infant Formula, which represents the NTP's opinion on the potential for exposure to soy infant formula to cause adverse developmental effects in humans. The NTP concurred with the expert panel that there is minimal concern for adverse effects on development in infants who consume soy infant formula. This conclusion was based on information about soy infant formula provided in the expert panel report, public comments received during the course of the expert panel evaluation, additional scientific information made available since the expert panel meeting, and peer reviewer critiques of the draft NTP Brief by the NTP Board of Scientific Counselors (BSC) on May 10, 2010 (Meeting materials are available at http://ntp.niehs.nih.gov/go/9741.). The BSC voted in favor of the minimal concern conclusion with 7 yes votes, 3 no votes, and 0 abstentions. One member thought that the conclusion should be negligible concern and two members thought that the level of concern should be higher than minimal concern. The NTP's response to the May 10, 2010 review ("peer-review report") is available on the NTP website at http://ntp.niehs.nih.gov/go/9741. The monograph includes the NTP Brief on Soy Infant Formula as well as the entire final Expert Panel Report on Soy Infant Formula. Public comments received as part of the NTP's evaluation of soy infant formula and other background materials are available at http://cerhr.niehs.nih.gov/evals/index.html.

Genistein impairs early testosterone production in fetal mouse testis via estrogen receptor alpha

The widespread consumption of soy-based products raises the issue of the reproductive toxicity of phytoestrogens. Indeed, it is well known that genistein, an isoflavone found in soybeans and soy products, mimics the actions of estrogens and that the fetal testis is responsive to estrogens. Therefore we investigated whether genistein could have deleterious effects on fetal testis. Using organ cultures of fetal testes from wild type and ERα or ERβ knock-out mice we show that genistein inhibits testosterone secretion by fetal Leydig cells during early fetal development (E12.5), within the "masculinization programming window". This effect occurs through an ERα-dependent mechanism and starting at 10 nM genistein, a concentration which is compatible with human consumption. No effect of genistein on the number of gonocytes was detected at any of the studied developmental stages. These results suggest that fetal exposure to phytoestrogens can affect the development and function of the male reproductive system.

Impact of dietary soy isoflavones in pregnancy on fetal programming of endothelial function in offspring

Epidemiological evidence suggests that soy-based diets containing phytoestrogens (isoflavones) afford protection against cardiovascular diseases (CVDs); however, supplementation trials have largely reported only marginal health benefits. The molecular mechanisms by which the isoflavones genistein, daidzein, and equol afford protection against oxidative stress remain to be investigated in large scale clinical trials. Isoflavones are transferred across the placenta in both rodents and humans, yet there is limited information on their actions in pregnancy and the developmental origins of disease. Our studies established that feeding a soy isoflavone-rich diet during pregnancy, weaning, and postweaning affords cardiovascular protection in aged male rats. Notably, rats exposed to a soy isoflavone-deficient diet throughout pregnancy and adult life exhibited increased oxidative stress, diminished antioxidant enzyme and eNOS levels, endothelial dysfunction, and elevated blood pressure in vivo. The beneficial effects of refeeding isoflavones to isoflavone-deficient rats include an increased production of nitric oxide and EDHF, an upregulation of antioxidant defense enzymes and lowering of blood pressure in vivo. This review focuses on the role that isoflavones in the fetal circulation may play during fetal development in affording protection against CVD in the offspring via their ability to activate eNOS, EDHF, and redox-sensitive gene expression.

Endocrine milieu and erectile dysfunction: is oestradiol-testosterone imbalance, a risk factor in the elderly?

Oestrogens are not exclusive to the female gender but occur in moderate circulating levels of 25-70 pg ml⁻¹ in men, compared to 44-153 pg ml⁻¹ in women. Arising from aromatisation of testosterone (T), oestrogen is considered to have many opposing physiological functions and the progressive T decline in the aging male is associated with relative and/or absolute increase in serum oestradiol (E₂). Sexual disinterest and erectile dysfunction (ED) in the elderly may well be due to pathophysiological E₂-T imbalance; the altered hormonal ratio may also explain the higher incidence of ED in hyperestrogenism or following exposure to environmental/plant oestrogens.