Estrogenic activity of flavonoids in mice. The importance of estrogen receptor distribution, metabolism and bioavailability

Perspective: Observational Studies Involving Low-Soy Intake Populations Have Limited Ability for Providing Insight into the Health Effects of Soybean Isoflavones

Isoflavones are naturally occurring plant compounds found in uniquely high amounts in soybeans and foods made from this legume. These soybean constituents have been proposed to exert several health benefits and as such they have been the subject of an enormous amount of research. This research includes randomized controlled trials (RCTs) and epidemiologic investigations. Although statistically significant associations between isoflavone intake and a wide range of health outcomes have been identified in cohorts involving low-isoflavone intake populations, we suggest that these associations are unlikely to have a causal basis because exposure is too low for isoflavones to exert physiologic effects. In cohorts involving predominantly non-Asian, non-vegetarian populations, the highest isoflavone intake category is typically ≤3 mg/d, an amount of isoflavones provided by ∼30 mL (2 tablespoons) of soymilk made from whole soybeans. In comparison, mean isoflavone intake in the upper intake categories in observational studies involving high-isoflavone intake populations is typically ≥50 mg/d. In RCTs, intervention doses of isoflavones typically range between 40 and 100 mg/d. Health professionals advising patients and clients about soy food and isoflavone intake need to be aware of the limitations of epidemiologic research involving low-isoflavone intake populations. Intake recommendations are best based on the results of RCTs using clinically relevant doses of isoflavones and epidemiologic studies involving populations for whom soy foods are a habitual part of the diet.

Estrogenic flavonoids and their molecular mechanisms of action

Flavonoids are a major group of phytoestrogens associated with physiological effects, and ecological and social impacts. Although the estrogenic activity of flavonoids was reported by researchers in the fields of medical, environmental and food studies, their molecular mechanisms of action have not been comprehensively reviewed. The estrogenic activity of the respective classes of flavonoids, anthocyanidins/anthocyanins, 2-arylbenzofurans/3-arylcoumarins/α-methyldeoxybenzoins, aurones/chalcones/dihydrochalcones, coumaronochromones, coumestans, flavans/flavan-3-ols/flavan-4-ols, flavanones/dihydroflavonols, flavones/flavonols, homoisoflavonoids, isoflavans, isoflavanones, isoflavenes, isoflavones, neoflavonoids, oligoflavonoids, pterocarpans/pterocarpenes, and rotenone/rotenoids, was summarized through a comprehensive literature search, and their structure-activity relationship, biological activities, signaling pathways, and applications were discussed. Although the respective classes of flavonoids contained at least one chemical mimicking estrogen, the mechanisms varied, such as those with estrogenic, anti-estrogenic, non-estrogenic, and biphasic activities, and additional activities through crosstalk/bypassing, which exert biological activities through cell signaling pathways. Such mechanistic variations of estrogen action are not limited to flavonoids and are observed among other broad categories of chemicals, thus this group of chemicals can be termed as the "estrogenome". This review article focuses on the connection of estrogen action mainly between the outer and the inner environments, which represent variations of chemicals and biological activities/signaling pathways, respectively, and form the basis to understand their applications. The applications of chemicals will markedly progress due to emerging technologies, such as artificial intelligence for precision medicine, which is also true of the study of the estrogenome including estrogenic flavonoids.

Countermeasure efficacy of apigenin for silicon-ion-induced early damage in blood and bone marrow of exposed C57BL/6J mice

We investigated the countermeasure efficacy of apigenin (AP), given as a diet supplement, for radiation-induced damage in the hematopoietic tissues collected on day 7 after a total-body exposure of male C57BL/6J mice to 0 or 0.5 Gy of 260 MeV/n silicon (²⁸Si) ions. We gave food with AP at the concentration of 20 mg/kg body weight (bw) (AP20) or without AP (AP0) to mice before and after irradiation. There were four groups of mice (six mice in each): Group 1- Control, i.e. No Radiation (0 Gy) with AP0; Group 2 - Radiation (0.5 Gy) with AP0; Group 3 - No Radiation (0 Gy) with AP20; and Group 4 - Radiation (0.5 Gy) with AP20. The complete blood count (CBC) and differential blood count were performed for each mouse. In the same mouse, an anti-clastogenic activity of AP was evaluated using the in vivo blood-erythrocyte micronucleus (MN) assay. Further in each mouse, bone marrow (BM) cells were collected and used for measuring the levels of activated nuclear factor-kappa B (NF-κB), and pro-inflammatory cytokines (i.e. tumor necrotic factor-alpha (TNF-α), interleukin-1α (IL-1α), IL-1 beta (IL-1β), and IL-6). We used the colony-forming unit assay (CFU-A) as a tool to study the countermeasure efficacy of AP against the harmful effects of ²⁸Si ions on the proliferation of the hematopoietic stem/progenitor cells (HSPCs). Our results showed that AP is highly effective not only in the prevention of leukopenia and thrombocytopenia but also in the enhancement of erythropoiesis and the proliferation of HSPCs. We also observed the potent anti-clastogenic activity of AP given to mice as a diet supplement. Further, we found that AP is very effective in the suppression of activated NF-κB and pro-inflammatory cytokines, suggesting that AP given as a diet supplement protects mice from ²⁸Si-ion-induced damage in the hematopoietic tissues of irradiated male C57BL/6J mice via its anti-inflammation activity.

In utero exposure to low doses of genistein and di-(2-ethylhexyl) phthalate (DEHP) alters innate immune cells in neonatal and adult rat testes

BACKGROUND

Although humans are exposed to mixtures of endocrine disruptor chemicals, few studies have examined their toxicity on male reproduction. We previously found that fetal exposure to a mixture of the phytoestrogen genistein (GEN) and the plasticizer di(2-ethylhexyl) phthalate (DEHP) altered gene expression in adult rat testes.

OBJECTIVES

Our goal was to investigate the effects of fetal exposure to GEN-DEHP mixtures at two doses relevant to humans on testicular function and transcriptome in neonatal and adult rats.

MATERIALS AND METHODS

Pregnant SD rats were gavaged with vehicle, GEN or DEHP, alone or mixed at 0.1 and 10 mg/kg/day, from gestation day 14 to birth. Fertility, steroid levels, and testis morphology were examined in neonatal and adult rats. Testicular transcriptomes were examined by gene array and functional pathway analyses. Cell-specific genes/proteins were determined by quantitative real-time PCR and immunohistochemistry.

RESULTS

GEN-DEHP mixtures increased the rates of infertility and abnormal testes in adult rats. Gene array analysis identified more genes exclusively altered by the mixtures than individual compounds. Altered top canonical pathways included urogenital/reproductive developmental and inflammatory processes. GEN-DEHP mixtures increased innate immune cells and macrophages markers at both doses and ages, more strongly and consistently than DEHP or GEN alone. Genes exclusively increased by the mixture in adult testis related to innate immune cells and macrophages included Kitlg, Rps6ka3 (Rsk2), Nr3c1, Nqo1, Lif, Fyn, Ptprj (Dep-1), Gpr116, Pfn2, and Ptgr1.

DISCUSSION AND CONCLUSION

These findings demonstrate that GEN-DEHP mixtures at doses relevant to human induce adverse testicular phenotypes, concurrent with age-dependent and non-monotonic changes in testicular transcriptomes. The involvement of innate immune cells such as macrophages suggests immediate and delayed inflammatory responses which may contribute to testicular dysfunction. Moreover, these effects are complex and likely involve multiple interactions between immune and non-immune testicular cell types that will entail further studies.

Investigation of the role of herbal medicine, acupressure, and acupuncture in the menopausal symptoms: An evidence-based systematic review study

Background

Menopause is an important physiological phenomenon in women's lives. Women's concern about taking the hormone treatment to ease menopausal symptoms is increasing. Over the past decade, the use of complementary and alternative medicine for the treatment of menopausal problems instead of hormone therapy has increased.

Objective

This study aimed to investigate the role of herbal medicine, acupressure, and acupuncture in the menopausal symptoms.

Methods

Data source: related articles were searched from internal scientific databases and external databases of "Web of Scopus, Cochrane, PubMed, Science Direct, Ovid, and Google scholar."

Study Eligibility Criteria

The keywords such as menopause, menopausal symptoms, complementary menopausal medicine, acupuncture in menopause, herbal medicine in menopause, and acupuncture in menopause were searched in the studies from 1987 to 2019. Exclusion criteria were inadequate information in the study, lack of access to full-text articles, animal studies, and reports. At the end of the search, 145 articles out of a total of 400 articles were reviewed.

Results

In various studies, different herbs such as licorice, valerian, soy, sage, ginseng, etc., were used to improve menopausal symptoms. In addition, acupuncture and acupressure were used to reduce menopausal symptoms.

Conclusion

The efficacy and use of complementary and alternative medicine, along with other classical medicine care, can be a new model for improving menopausal symptoms in women. It is recommended that further clinical and review studies be conducted to develop complementary and alternative medicine.

K. J, G. JKU, K.M. P, Balachandran I. Identification of validated substitute for Asoka (Saraca asoca (Roxb.) Willd.) by phytochemical and pharmacological evaluations

Background

Asoka is an important drug used in many Ayurvedic formulations. The bark of Saraca asoca (Roxb.) Willd. is the genuine source plant for Asoka. Due to diminishing availability and increasing requirement, the Ayurvedic industry is facing acute shortage of this crude drug. It is usual that traders try to deceive the consumers by tendering similar bark of other trees. The unscientific substitution may affect the quality of herbal preparations adversely. The aim of the present study is to identify a scientifically validated substitute for Asoka.

Results

Phytochemical and pharmacological evaluation has been carried out using plant parts of four medicinal plants viz, Saraca asoca (AB), Polyalthia longifolia (PB), Shorea robusta (SB), and Trema orientalis (TB). The results of the study showed that among the tested extracts, AB and SB showed significant dose-dependent protection against bilateral ovariectomy-induced changes in estrus cycle, uterus weights, and lipid profile. LC/MS analysis revealed the presence of active catechins in both AB and SB. Polyalthia longifolia, the common adulterant of Asoka, showed entirely different chemical and biological properties.

Conclusion

This study concluded the possibility of using S. robusta bark as substitute for Asoka.

Graphical abstract

Marantodes pumilum (Blume) Kuntze (Kacip Fatimah) stimulates uterine contraction in rats in post-partum period

ETHNOPHARMACOLOGICAL RELEVANCE

Marantodes pumilum (Blume) Kuntze has traditionally been used to firm the uterus after delivery, however scientific evidences behind this claim is still lacking.

AIMS OF STUDY

To demonstrate Marantodes pumilum leaves aqueous extract (MPE) has an effect on uterine contraction after delivery and to elucidate the molecular mechanisms involved.

METHODS

Day-1 post-delivery female rats were given MPE (100, 250 and 500 mg/kg/day) orally for seven consecutive days. A day after the last treatment (day-8), rats were sacrificed and uteri were harvested and subjected for ex-vivo contraction study using organ bath followed by protein expression and distribution study by Western blotting and immunohistochemistry techniques, respectively. The proteins of interest include calmodulin-CaM, myosin light chain kinase-MLCK, sarcoplasmic reticulum Ca²⁺-ATPase (SERCA), G-protein α and β (Gα and Gβ), inositol-triphosphate 3-kinase (IP3K), oxytocin receptor-OTR, prostaglandin (PGF)2α receptor-PGFR, muscarinic receptor-MAChR and estrogen receptor (ER) isoforms α and β. Levels of estradiol and progesterone in serum were determined by enzyme-linked immunoassay (ELISA).

RESULTS

Ex-vivo contraction study revealed the force of uterine contraction increased with increasing doses of MPE. In addition, expression of CaM, MLCK, SERCA, Gα, Gβ, IP3K, OTR, PGF2α, MAChR, Erα and ERβ in the uterus increased with increasing doses of MPE. Serum analysis indicate that estradiol levels decreased while progesterone levels remained low at day-8 post-partum in rats receiving 250 and 500 mg/kg/day MPE.

CONCLUSIONS

These findings support the claims that MPE help to firm the uterus and pave the way for its use as a uterotonic agent after delivery.

LC-ESI-MS/MS method for the simultaneous determination of isoformononetin, daidzein, and equol in rat plasma: Application to a preclinical pharmacokinetic study

Isoformononetin (methoxy isoflavone) is a potent osteogenic isoflavone abundantly present in Butea monosperma, Pisum sativum, Mung bean, Machaerium villosum, Medicago sativa, and Glycine max. In the current study, an LC-ESI-MS/MS method for the simultaneous evaluation of isoformononetin (IFN), daidzein (DZN) and equol (EQL) was developed and validated in rat plasma using biochanin A as an internal standard. IFN, DZN, and EQL separation was achieved by using acetonitrile and acetic acid (0.1%) in the ratio of 90:10 (% v/v) as mobile phase under isocratic conditions at a flow rate of 0.6 mL/min on Atlantis C₁₈ (4.6 × 250 mm, 5.0 μm) column. The achieved method was linear within the concentration range of 0.5-500 ng/mL. The method was effectively applied to investigate the permeability, protein binding estimation and pharmacokinetics studies of IFN in rats. The PAMPA permeability of IFN was found to be high at pH 4.0 and 7.0. The protein binding was found to be about 91% of IFN. The oral bioavailability of IFN was found to be poor (21.6%). IFN was found to have a moderate clearance (2.9 L/h/kg) and a large apparent volume of distribution (12.1 L/kg). The plasma half-life (t_1/2) and maximum attainable concentration (C_max) of IFN at systemic circulation was found to be 1.9 ± 0.6 h and 269.3 ± 0.4 after oral administration.

Biological Activities of Lactose-Based Prebiotics and Symbiosis with Probiotics on Controlling Osteoporosis, Blood-Lipid and Glucose Levels

Lactose-based prebiotics are synthesized by enzymatic- or microbial- biotransformation of lactose and have unique functional values. In this comprehensive review article, the biochemical mechanisms of controlling osteoporosis, blood-lipid, and glucose levels by lactose-based prebiotics and symbiosis with probiotics are reported along with the results of clinical investigations. Interaction between lactose-based prebiotics and probiotics reduces osteoporosis by (a) transforming insoluble inorganic salts to soluble and increasing their absorption to gut wall; (b) maintaining and protecting mineral absorption surface in the intestine; (c) increasing the expression of calcium-binding proteins in the gut wall; (d) remodeling osteoclasts and osteoblasts formation; (e) releasing bone modulating factors; and (f) degrading mineral complexing phytic acid. Lactose-based prebiotics with probiotics control lipid level in the bloodstream and tissue by (a) suppressing the expressions of lipogenic- genes and enzymes; (b) oxidizing fatty acids in muscle, liver, and adipose tissue; (c) binding cholesterol with cell membrane of probiotics and subsequent assimilation by probiotics; (d) enzymatic-transformations of bile acids; and (e) converting cholesterol to coprostanol and its defecation. Symbiosis of lactose-based prebiotics with probiotics affect plasma glucose level by (a) increasing the synthesis of gut hormones plasma peptide-YY, glucagon-like peptide-1 and glucagon-like peptide-2 from entero-endocrine L-cells; (b) altering glucose assimilation and metabolism; (c) suppressing systematic inflammation; (d) reducing oxidative stress; and (e) producing amino acids. Clinical investigations show that lactose-based prebiotic galacto-oligosaccharide improves mineral absorption and reduces hyperlipidemia. Another lactose-based prebiotic, lactulose, improves mineral absorption, and reduces hyperlipidemia and hyperglycemia. It is expected that this review article will be of benefit to food technologists and medical practitioners.

Biochanin A extirpates the epithelial-mesenchymal transition in a human lung cancer

The natural iso-flavonoid, biochanin A, is categorized as a phytoestrogen and has been demonstrated to exhibit various pharmacological properties. However, no effects of biochanin A on lung cancer cell lines have been reported. Therefore, the present study aimed to demonstrate whether biochanin A has the ability to reduce lung cancer triggered pro-inflammatory effects from leukemic monocytes. We studied the release of cytokines, tumor necrosis factor (TNF)-α and interleukin (IL)-6, from the cocultured cells of A427:AML-193. In addition to this, epithelial-mesenchymal transition was also monitored. In the cocultured A427 and AML-193, AML-193 was stimulated by A427 cells assisting the release of TNF-α and IL-6 cytokines, but the addition of A427 with biochanin A reduced A427-triggered generation of cytokines by AML-193. Moreover, this non-functional A427:AML-193 coculture reduced the metastasis effects of A427 cells, as determined by wound healing assays and migration/invasion assays. These results were further confirmed by a reduction in Snail and E-cadherin expression levels, which are indicators of the epithelial-mesenchymal transition. These findings suggest the therapeutic effect of biochanin A against lung cancer evoked inflammation and pro-inflammatory functions from monocytic cells.

Effect of soy isoflavone supplementation on plasma lipoprotein(a) concentrations: A meta-analysis

BACKGROUND

Soy supplementation has been shown to reduce total and low-density lipoprotein cholesterol, while increasing high-density lipoprotein cholesterol. However, contradictory effects of soy isoflavone supplementation on lipoprotein(a) [Lp(a)] have been reported suggesting the need for a meta-analysis to be undertaken.

OBJECTIVE

The aim of the study was to investigate the impact of supplementation with soy isoflavones on plasma Lp(a) levels through a systematic review and meta-analysis of eligible randomized placebo-controlled trials.

METHODS

The search included PubMed-Medline, Scopus, ISI Web of Knowledge, and Google Scholar databases (by March 26, 2017), and quality of studies was evaluated according to Cochrane criteria. Quantitative data synthesis was performed using a random-effects model, with standardized mean difference and 95% confidence interval as summary statistics. Meta-regression and leave-one-out sensitivity analysis were performed to assess the modifiers of treatment response.

RESULTS

Ten eligible studies comprising 11 treatment arms with 973 subjects were selected for the meta-analysis. Meta-analysis did not suggest any significant alteration of plasma Lp(a) levels after supplementation with soy isoflavones (standardized mean difference: 0.08, 95% confidence interval: -0.05, 0.20, P = .228). The effect size was robust in the leave-one-out sensitivity analysis. In meta-regression analysis, neither dose nor duration of supplementation with soy isoflavones was significantly associated with the effect size.

CONCLUSION

This meta-analysis of the 10 available randomized placebo-controlled trials revealed no significant effect of soy isoflavones treatment on plasma Lp(a) concentrations.

Phytochemicals Targeting Estrogen Receptors: Beneficial Rather Than Adverse Effects?

In mammals, the effects of estrogen are mainly mediated by two different estrogen receptors, ERα and ERβ. These proteins are members of the nuclear receptor family, characterized by distinct structural and functional domains, and participate in the regulation of different biological processes, including cell growth, survival and differentiation. The two estrogen receptor (ER) subtypes are generated from two distinct genes and have partially distinct expression patterns. Their activities are modulated differently by a range of natural and synthetic ligands. Some of these ligands show agonistic or antagonistic effects depending on ER subtype and are described as selective ER modulators (SERMs). Accordingly, a few phytochemicals, called phytoestrogens, which are synthesized from plants and vegetables, show low estrogenic activity or anti-estrogenic activity with potentially anti-proliferative effects that offer nutraceutical or pharmacological advantages. These compounds may be used as hormonal substitutes or as complements in breast cancer treatments. In this review, we discuss and summarize the in vitro and in vivo effects of certain phytoestrogens and their potential roles in the interaction with estrogen receptors.

Phytosteroids beyond estrogens: Regulators of reproductive and endocrine function in natural products

Foods and botanical supplements can interfere with the endocrine system through the presence of phytosteroids - chemicals that interact with steroids receptors. Phytoestrogens are well studied, but compounds such as kaempferol, apigenin, genistein, ginsenoside Rf, and glycyrrhetinic acid have been shown to interact with non-estrogen nuclear receptors. These compounds can have agonist, antagonist, or mixed agonist/antagonist activity depending on compound, receptor, cell line or tissue, and concentration. Some phytosteroids have also been shown to inhibit steroid metabolizing enzymes, resulting in biological effects through altered endogenous steroid concentrations. An interesting example, compound A (4-[1-chloro-2-(methylamino)ethyl]phenyl acetate hydrochloride (1:1)) is a promising selective glucocorticoid receptor modulator (SGRM) based on a phytosteroid isolated from Salsola tuberculatiformis Botschantzev. Given that $6.9 billion of herbal supplements are sold each year, is clear that further identification and characterization of phytosteroids is needed to ensure the safe and effective use of botanical supplements.

In vivo prediction of CYP-mediated metabolic interaction potential of formononetin and biochanin A using in vitro human and rat CYP450 inhibition data

Formononetin (FMN) and Biochanin A (BCA) are the principal isoflavones present in commercially available extracts of red clover that are widely been consumed for various health benefits. We investigated the in vitro effects of FMN and BCA on catalytic activity of human/rat cytochrome P450 enzymes to assess the drug interaction potential of red clover. IC50 and Ki values of FMN and BCA for CYPs were determined in human/rat liver microsomes. FMN and BCA showed concentration-dependent inhibition of CYP1A2 activity with IC50 values of 13.42 and 24.98μM in human liver microsomes and 38.57 and 11.86μM in rat liver microsomes, respectively. The mode of inhibition of human CYP1A2 by FMN was found to be competitive with apparent Ki value of 10.13±1.96μM. FMN also inhibited human CYP2D6. BCA exerted moderately inhibitory effects on human CYP2C9. The predicted in vivo inhibition for CYP1A2 was insignificant (R value <1.1) at hepatic level while at intestinal level, it was significant (R value >11). The inhibitory effects on other CYPs were found to be minimal. Red clover may be considered safe to be consumed along with co-prescribed medications; however, precaution must be taken while co-administering it with CYP1A2 substrates.

Behavioral effects of Citrus limon in rats

Anxiety and depression are increasing worldwide, however these disorders may be managed by making healthier changes is dietary pattern, since there are evidences that diet rich in antioxidants and vitamins help reduce anxiety and depression. Hence present study was designed to evaluate the behavioral effects of Citrus limon in rats at three different doses i.e. 0.2, 0.4 and 0.6 ml/kg considered as low, moderate and high doses. Anxiolytic and antidepressant activities were specifically assessed twice during 15 days using open field test, elevated plus maze and forced swimming test. In open field test C. limon, revealed increase in distance travelled, number of central entries and number of rearing's at moderate dose, while in the elevated plus maze, number of open arm entries were found to be increased. Whereas in forced swimming test, there was decrease in duration of immobility and increase in duration of climbing. Thus results of present study suggest that C. limon at moderate dose have anxiolytic effect.

The estrogenic effects of apigenin, phloretin and myricetin based on uterotrophic assay in immature Wistar albino rats

Chemicals that occur in vegetal food and known as phytoestrogens, because of their structures similarity to estrogen, have benefits on chronic diseases. Despite this, when they are taken at high amounts, they can cause harmful effects on endocrine system of human and animals. In this study, it has been intended to determine the estrogenic potencies of phytoestrogens apigenin, phloretin and myricetin whose affinities for estrogen receptors in vitro. The female rats divided into 17 groups, each containing six rats. There was a negative control group and there were positive control dose groups which contains ethinyl estradiol, ethinyl estradiol+tamoxifen and genistein. The other dose groups which were tested for estrogenic activity contains apigenin, myricetin and phloretin All chemicals have been given to Wistar immature female rats with oral gavage for 3 consecutive days. By using uterotrophic analysis, uterus wet and blotted weights, vaginal opening, uterus length of female rats has been recorded at the end of the experiment. For detect of cell response, luminal epithelium height, gland number and lactoferrin intensity in luminal epithelium of uterus were evaluated. Biochemical analysises in blood were performed. Relative uterus weights of rats in 100 mg/kg/day dose group of myricetin were statistically increased according to vehicle control and positive control groups. In dose groups of apigenin and phloretin it was found that there were cell responses in uterus. All treatment groups had a significant difference in the high intensity of lactoferrin and uterine gland count compared to oil control group. There was no difference between phloretin and apigenin treatment groups in uterine weight statictically. Uterine heights were increased in positive control groups and 100 mg/kg/day dose group of myricetin. Epithelial cell heights were increased in treatment groups except apigenin and phloretin dose groups. There was no difference between all treatment groups in vaginal opening values according to positive control.

Flavonoids induce the synthesis and secretion of neurotrophic factors in cultured rat astrocytes: a signaling response mediated by estrogen receptor

Neurotrophic factors are playing vital roles in survival, growth, and function of neurons. Regulation of neurotrophic factors in the brain has been considered as one of the targets in developing drug or therapy against neuronal disorders. Flavonoids, a family of multifunctional natural compounds, are well known for their neuronal beneficial effects. Here, the effects of flavonoids on regulating neurotrophic factors were analyzed in cultured rat astrocytes. Astrocyte is a major secreting source of neurotrophic factors in the brain. Thirty-three flavonoids were screened in the cultures, and calycosin, isorhamnetin, luteolin, and genistein were identified to be highly active in inducing the synthesis and secretion of neurotrophic factors, including nerve growth factor (NGF), glial-derived neurotrophic factor (GDNF), and brain-derived neurotrophic factor (BDNF). The inductions were in time- and dose-dependent manners. In cultured astrocytes, the phosphorylation of estrogen receptor was triggered by application of flavonoids. The phosphorylation was blocked by an inhibitor of estrogen receptor, which in parallel reduced the flavonoid-induced expression of neurotrophic factors. The results proposed the role of flavonoids in protecting brain diseases, and therefore these flavonoids could be developed for health food supplement for patients suffering from neurodegenerative diseases.

Phytotherapeutic management of polycystic ovary syndrome: role of aerial parts of wood betony (Stachys lavandulifolia)

Pharmacological treatments of polycystic ovary syndrome (PCOS) have side effects. We compared the efficacy and safety of the aerial parts of wood botany (AWB) with those of Medroxyprogesterone acetate (MPA) in the management of abnormal uterine bleeding (AUB) due to PCOS. We conducted a randomized clinical trial of 66 women aged 15-45 years, with AUB. Participants were randomly assigned to either cyclical 10-mg BD MPA for three cycles or 5 g ABW TDS for three months. Clinical symptoms and paraclinical parameters were recorded before and 3 months after initiation of the treatment. Comparisons were made using generalized linear models. Age-adjusted prevalence rate of different patterns of AUB, decreased from 2.7 (95%CIs: 0.6-48.0) to 1.1 (95%CIs: 0.1-18.3) for patients taking MPA, and from 2.5 (95% CIs: 0.2-40.2) to 0.7 (95%CIs: 0.0-12.1). Decrease in prevalence rate was similar across two arms of the study (P value = 0.248). Adverse effects were observed less frequently (24.2%) among participants on MPA than among those on AWB (45.5%). The multivariate-adjusted odds for developing adverse reaction of MPA was 0.40 (95%CIs: 0.14-1.19, P value = 0.099) time odds of AWB. In conclusion, AWB may be used as an alternative for MPA in the treatment of AUB caused by PCOS.

Kaempferol Exhibits Progestogenic Effects in Ovariectomized Rats

OBJECTIVE

Progesterone (P₄) plays a central role in women's health. Synthetic progestins are used clinically in hormone replacement therapy (HRT), oral contraceptives, and for the treatment of endometriosis and infertility. Unfortunately, synthetic progestins are associated with side effects, including cardiovascular disease and breast cancer. Botanical dietary supplements are widely consumed for the alleviation of a variety of gynecological issues, but very few studies have characterized natural compounds in terms of their ability to bind to and activate progesterone receptors (PR). Kaempferol is a flavonoid that functions as a non-steroidal selective progesterone receptor modulator (SPRM) in vitro. This study investigated the molecular and physiological effects of kaempferol in the ovariectomized rat uteri.

METHODS

Since genistein is a phytoestrogen that was previously demonstrated to increase uterine weight and proliferation, the ability of kaempferol to block genistein action in the uterus was investigated. Analyses of proliferation, steroid receptor expression, and induction of well-established PR-regulated targets Areg and Hand2 were completed using histological analysis and qPCR gene induction experiments. In addition, kaempferol in silico binding analysis was completed for PR. The activation of estrogen and androgen receptor signalling was determined in vitro.

RESULTS

Molecular docking analysis confirmed that kaempferol adopts poses that are consistent with occupying the ligand-binding pocket of PRA. Kaempferol induced expression of PR regulated transcriptional targets in the ovariectomized rat uteri, including Hand2 and Areg. Consistent with progesterone-l ke activity, kaempferol attenuated genistein-induced uterine luminal epithelial proliferation without increasing uterine weight. Kaempferol signalled without down regulating PR expression in vitro and in vivo and without activating estrogen and androgen receptors.

CONCLUSION

Taken together, these data suggest that kaempferol is a unique natural PR modulator that activates PR signaling in vitro and in vivo without triggering PR degradation.

Impact of food matrix on isoflavone metabolism and cardiovascular biomarkers in adults with hypercholesterolemia

The role of food matrix and gender on soy isoflavone metabolism and biomarkers of activity were examined in twenty free-living adults (34.7 ± 11.5 years old) with hypercholesterolemia (221.9 ± 18.7mg dL(-1)). In a randomized crossover design study, participants consumed soy bread (3 wk) or a soy beverage (3 wk) containing 20 g soy protein with 99 and 93 mg isoflavones aglycone equivalents per day, respectively. During soy bread intervention, women had significantly greater microbial metabolite excretion (P = 0.05) of isoflavonoids than men. In men, isoflavone metabolite excretion was not discernibly different between the two matrices. Significant reductions (P≤ 0.05) in triglycerides (24.8%), LDL cholesterol (6.0%), apolipoprotein A-I (12.3%), and lipid oxidative stress capacity (25.5%), were observed after soy food intervention. Our findings suggest that the food matrix significantly impacts soy isoflavone metabolism, particularly microbial metabolites in women.

Influence of fructooligosaccharide on pharmacokinetics of isoflavones in postmenopausal women

The objective of the present paper was to determine the influence of fructooligosaccharide (FOS) on the pharmacokinetics of isoflavones in healthy postmenopausal women. The study was a fixed-sequence, two-phase, crossover study. Twelve subjects received a single oral dose of 300 mL of a soy beverage. Blood samples were collected before the dose and at 0.5, 1, 2, 4, 6, 8, 10, 12, 24, and 32 h after the administration of the soy beverage. After a washout period of at least 1 week, subjects were assigned to receive oral doses of FOS, 5 g each time, twice a day (after breakfast and dinner) for 14 days, followed by a single oral dose of the same soy beverage on the next day. Blood samples were then collected at the same time points mentioned previously. Plasma isoflavone concentrations were determined by HPLC. Continuous oral administrations of FOS followed by a single oral administration of soy beverage caused significant increases in C_max, AUC_0–32, and AUC_0–∞ of genistein and AUC_0–32 of daidzein, comparing to those obtained following a single oral dose of soy beverage alone. Other pharmacokinetic parameters (T_max and t_1/2 of both aglycones and AUC_0–∞ of daidzein) between both regimens were not significantly different.

Polyphenol content of plasma and litter after the oral administration of green tea and tea polyphenols in chickens

Metabolic profiles of broiler chickens were examined after the ingestion of green tea, tea polyphenols, and (-)-epigallocatechin-3-gallate (EGCG). Solid-phase extraction of serum and litters yielded free catechins and their metabolites, which were then identified and quantified by liquid chromatography-tandem mass spectrometry. In plasma samples, (-)-gallocatechin, (+)-catechin, and EGCG were detected in the green tea group; pyrogallol acid, (epi)catechin-O-sulfate, 4'-O-methyl-(epi)gallocatechin-O-glucuronide, and (epi)catechin-3'-O-glucuronide were detected in the tea polyphenols group; and EGCG, (-)-gallocatechin gallate (GCG), and 4'-O-methyl-(epi)gallocatechin-O-glucuronides were detected in the EGCG group. In litters, gallic acid, EGCG, GCG, and ECG were detected in the green tea and tea polyphenols groups; EGCG and ECG were detected in the EGCG group. The conjugated metabolites, 4'-O-methyl-(epi)gallocatechin-O-glucuronide, (epi)catechin-3'-glucuronide, and 4'-O-methyl-(epi)catechin-O-sulfate, were identified in the green tea group; 4'-O-methyl-(epi)catechin-O-sulfate and 4'-O-methyl-(epi)gallocatechin-O-sulfate were identified in the tea polyphenols group; only 4'-O-methyl-(epi)gallocatechin-O-sulfate was detected in the EGCG group. The excretion of tea catechins was 95.8, 87.7, and 97.7% for the green tea, tea polyphenols, and EGCG groups, respectively.

Time to include the gut microbiota in the hygienic standardisation of laboratory rodents

The gut microbiota (GM) composition and its impact on animal experiments has become currently dramatically relevant in our days: (1) recent progress in metagenomic technologies, (2) the availability of large scale quantitative analyses to characterize even subtle phenotypes, (3) the limited diversity of laboratory rodent GM due to strict barriers at laboratory animal vendors, and (4) the availability of up to 300.000 different transgenic mouse strains from different sources displaying a huge variety in their GM composition. In this review the GM is described as a variable in animal experiments which need to be reduced for scientific as well as ethical reasons, and strategies how to implement this in routine diagnostic procedures are proposed. We conclude that we have both enough information available to state that the GM has an essential impact on animal models, as well as the methods available to start dealing with these impacts.

Vasorelaxant and antihypertensive effects of formononetin through endothelium-dependent and -independent mechanisms

AIM

To investigate the mechanisms underlying the vasorelaxant effect of formononetin, an O-methylated isoflavone, in isolated arteries, and its antihypertensive activity in vivo.

METHODS

Arterial rings of superior mesenteric arteries, renal arteries, cerebral basilar arteries, coronary arteries and abdominal aortas were prepared from SD rats. Isometric tension of the arterial rings was recorded using a myograph system. Arterial pressure was measured using tail-cuff method in spontaneously hypertensive rats.

RESULTS

Formononetin (1-300 μmol/L) elicited relaxation in arteries of the five regions that were pre-contracted by KCl (60 mmol/L), U46619 (1 μmol/L) or phenylephrine (10 μmol/L). The formononetin-induced relaxation was reduced by removal of endothelium or by pretreatment with L-NAME (100 μmol/L). Under conditions of endothelium denudation, formononetin (10, 30, and 100 μmol/L) inhibited the contraction induced by KCl and that induced by CaCl(2) in Ca(2+)-free depolarized medium. In the absence of extracellular Ca(2+), formononetin (10, 30, and 100 μmol/L) depressed the constriction caused by phenylephrine (10 μmol/L), but did not inhibit the tonic contraction in response to the addition of CaCl(2) (2 mmol/L). The contraction caused by caffeine (30 mmol/L) was not inhibited by formononetin (100 μmol/L). Formononetin (10 and 100 μmol/L) reduced the change rate of Ca(2+)-fluorescence intensity in response to KCl (50 mmol/L). In spontaneously hypertensive rats, formononetin (5, 10, and 20 mg/kg) slowly lowered the systolic, diastolic and mean arterial pressure.

CONCLUSION

Formononetin causes vasodilatation via two pathways: (1) endothelium-independent pathway, probably due to inhibition of voltage-dependent Ca(2+) channels and intracellular Ca(2+) release; and (2) endothelium-dependent pathway by releasing NO. Both the pathways may contribute to its antihypertensive effect.

Apigenin prevents development of medroxyprogesterone acetate-accelerated 7,12-dimethylbenz(a)anthracene-induced mammary tumors in Sprague-Dawley rats

The use of progestins as a component of hormone replacement therapy has been linked to an increase in breast cancer risk in postmenopausal women. We have previously shown that medroxyprogesterone acetate (MPA), a commonly administered synthetic progestin, increases production of the potent angiogenic factor vascular endothelial growth factor (VEGF) by tumor cells, leading to the development of new blood vessels and tumor growth. We sought to identify nontoxic chemicals that would inhibit progestin-induced tumorigenesis. We used a recently developed progestin-dependent mammary cancer model in which tumors are induced in Sprague-Dawley rats by 7,12-dimethylbenz(a)anthracene (DMBA) treatment. The flavonoid apigenin, which we previously found to inhibit progestin-dependent VEGF synthesis in human breast cancer cells in vitro, significantly delayed the development of, and decreased the incidence and multiplicity of, MPA-accelerated DMBA-induced mammary tumors in this animal model. Whereas apigenin decreased the occurrence of such tumors, it did not block MPA-induced intraductal and lobular epithelial cell hyperplasia in the mammary tissue. Apigenin blocked MPA-dependent increases in VEGF, and suppressed VEGF receptor-2 (VEGFR-2) but not VEGFR-1 in regions of hyperplasia. No differences were observed in estrogen or progesterone receptor (ER/PR) levels, or the number of estrogen receptor-positive cells, within the mammary gland of MPA-treated animals administered apigenin, MPA-treated animals, and placebo treated animals. However, the number of progesterone receptor-positive cells was reduced in animals treated with MPA or MPA and apigenin compared with those treated with placebo. These findings suggest that apigenin has important chemopreventive properties for those breast cancers that develop in response to progestins.

Antagonistic effects of gestational dietary exposure to low-dose vinclozolin and genistein on rat fetal germ cell development

Continuous, low-dose exposure to a phytoestrogen (1 mg/kg/day genistein) and/or to an antiandrogenic food contaminant (1 mg/kg/day vinclozolin) has been recently reported to affect male reproductive tract and fertility [1] in adults. We investigated whether alterations of the testis are already present at the end of in utero exposure using the same rat model and doses following exposure from conception to delivery. After vinclozolin exposure, we observed in the neonate a slight but significant alteration of steroidogenesis and gametogenesis with a reduction of testosterone secretion and of the number of gonocytes. In contrast, genistein exposure had no effect. While the vinclozolin-genistein mixture acts in a synergistic manner to induce the most significant alterations in the adult, interestingly, genistein antagonized the deleterious effect of vinclozolin on germ cells in the neonate. This difference emphasizes the importance of studying the effects of endocrine disruptors during various developmental stages to understand their effects.

Bioavailability challenges associated with development of anti-cancer phenolics

Phenolics including many polyphenols and flavonoids have the potentials to become chemoprevention and chemotherapy agents. However, poor bioavailability limits their biological effects in vivo. This paper reviews the factors that affect phenolics absorption and their bioavailabilities from the points of view of their physicochemical properties and disposition in the gastrointestinal tract. The up-to-date research data suggested that solubility and metabolism are the primary reasons that limit phenolic aglycones' bioavailability although stability and poor permeation may also contribute to the poor bioavailabilities of the glycosides. Future investigations should further optimize phenolics' bioavailabilities and realize their chemopreventive and chemotherapeutic effects in vivo.

Bioactivity of isoflavones: assessment through a theoretical model as a way to obtain a "Theoretical Efficacy Related to Estradiol (TERE)"

The increase of human life span will have profound implications in Public Health in decades to come. By 2030, there will be an estimated 1.2 billion women in post-menopause. Hormone Replacement Therapy with synthetic hormones is still full of risks and according to the latest developments, should be used for the shortest time possible. Searching for alternative drugs is inevitable in this scenario and science must provide physicians with other substances that can be used to treat the same symptoms with less side effects. Systematic research carried out on this field of study is focusing now on isoflavones but the randomised controlled trials and reviews of meta-analysis concerning post-menopause therapy, that could have an important impact on human health, are very controversial. The aim of the present work was to establish a theoretical calculation suitable for use as a way to estimate the “Theoretical Efficacy (TE)” of a mixture with different bioactive compounds as a way to obtain a “Theoretical Efficacy Related to Estradiol (TERE)”. The theoretical calculation that we propose in this paper integrates different knowledge about this subject and sets methodological boundaries that can be used to analyse already published data. The outcome should set some consensus for new clinical trials using isoflavones (isolated or included in mixtures) that will be evaluated to assess their therapeutically activity. This theoretical method for evaluation of a possible efficacy could probably also be applied to other herbal drug extracts when a synergistic or contradictory bio-effect is not verified. In this way, it we may contribute to enlighten and to the development of new therapeutic approaches.

Chronic dietary exposure to a low-dose mixture of genistein and vinclozolin modifies the reproductive axis, testis transcriptome, and fertility

BACKGROUND

The reproductive consequences and mechanisms of action of chronic exposure to low-dose endocrine disruptors are poorly understood.

OBJECTIVE

We assessed the effects of a continuous, low-dose exposure to a phytoestrogen (genistein) and/or an antiandrogenic food contaminant (vinclozolin) on the male reproductive tract and fertility.

METHODS

Male rats were exposed by gavage to genistein and vinclozolin from conception to adulthood, alone or in combination, at low doses (1 mg/kg/day) or higher doses (10 and 30 mg/kg/day). We studied a number of standard reproductive toxicology end points and also assessed testicular mRNA expression profiles using long-oligonucleotide microarrays.

RESULTS

The low-dose mixture and high-dose vinclozolin produced the most significant alterations in adults: decreased sperm counts, reduced sperm motion parameters, decreased litter sizes, and increased post implantation loss. Testicular mRNA expression profiles for these exposure conditions were strongly correlated. Functional clustering indicated that many of the genes induced belong to the "neuroactive ligand-receptor interactions" family encompassing several hormonally related actors (e.g., follicle-stimulating hormone and its receptor). All exposure conditions decreased the levels of mRNAs involved in ribosome function, indicating probable decreased protein production.

CONCLUSIONS

Our study shows that chronic exposure to a mixture of a dose of a phytoestrogen equivalent to that in the human diet and a low dose-albeit not environmental-of a common anti-androgenic food contaminant may seriously affect the male reproductive tract and fertility.

A comparison of the effects of soya isoflavonoids and fish oil on cell proliferation, apoptosis and the expression of oestrogen receptors alpha and beta in the mammary gland and colon of the rat

Isoflavonoids and fish oil may be protective against colorectal cancer, but the evidence in relation to breast cancer risk is ambiguous. In the present study, we have investigated the impact of soya-derived isoflavonoids and n-3 fatty acids from fish oil, both individually and in combination, on apoptosis, cell proliferation and oestrogen receptor (ER) expression in the colon and mammary gland of the rat. Female rats were fed diets high in n-3 fatty acids (80 g/kg diet) or soya protein (765 mg/kg diet isoflavones) for 2 weeks, and then killed before the removal of the colon and mammary glands. Cell proliferation and apoptosis were quantified morphologically in whole crypts and terminal end buds. The expressions of ERalpha and ERbeta were measured in colon tissue scrapes and the mammary gland. Fish oil significantly increased apoptosis and decreased mitosis in both tissues, an effect associated with a decrease in the expressions of ERalpha and ERbeta. Soya had no effect on apoptosis in either tissue, but reduced mitosis in the colon (P < 0.001) while increasing it in the mammary gland (P = 0.001). The changes in proliferation were associated with contrasting changes in the ER expression such that fish oil significantly decreased both ERbeta and ERalpha, while soya increased ERalpha and decreased ERbeta. The results may provide a novel mechanism by which n-3 fatty acids could reduce cancer risk, but the interpretation of the results in relation to soya consumption and breast cancer risk requires further investigation.

Apigenin causes G(2)/M arrest associated with the modulation of p21(Cip1) and Cdc2 and activates p53-dependent apoptosis pathway in human breast cancer SK-BR-3 cells

We studied the effects of apigenin on the cell cycle distribution and apoptosis of human breast cancer cells and explored the mechanisms underlying these effects. We first investigated the antiproliferative effects in SK-BR-3 cells exposed to between 1 and 100 microM apigenin for 24, 48 and 72 h. Apigenin significantly inhibited cell proliferation at concentrations over 50 microM, regardless of exposure time (P<.05), and resulted in significant cell cycle arrest in the G(2)/M phase after 48 h of treatment at high concentrations (50 and 100 microM; P<.05). To investigate the regulatory proteins of cell cycle arrest affected by apigenin, we treated cells with 50 and 100 microM apigenin for 72 h. Apigenin caused a slight decrease in cyclin D and cyclin E expression, with no change in CDK2 and CDK4. In addition, the apigenin-induced accumulation of the cell population in the G(2)/M phase resulted in a decrease in CDK1 together with cyclin A and cyclin B. In an additional study, apigenin also increased the accumulation of p53 and further enhanced the level of p21(Cip1), with no change in p27(Kip1). The expression of Bax and cytochrome c of p53 downstream target was increased markedly at high concentration treatment over 50 microM apigenin. Based on our findings, the mechanism by which apigenin causes cell cycle arrest via the regulation of CDK1 and p21(Cip1) and induction of apoptosis seems to be involved in the p53-dependent pathway.

Natural polyphenol disposition via coupled metabolic pathways

A major challenge associated with the development of chemopreventive polyphenols is the lack of bioavailability in vivo, which are primarily the result of coupled metabolic activities of conjugating enzymes and efflux transporters. These coupling processes are present in disposition tissues and organs in mammals and are efficient for the purposes of drug metabolism, elimination and detoxification. Therefore, it was expected that these coupling processes represent a significant barrier to the oral bioavailabilities of polyphenols. In various studies of this coupling process, it was identified that various conjugating enzymes such as uridine 5'-diphosphate-glucuronosyltransferase and sulfotransferase are capable of producing very hydrophilic metabolites of polyphenols, which cannot diffuse out of the cells and needs the action of efflux transporters to pump them out of the cells. Additional studies have shown that efflux transporters, such as multi-drug resistance-associated protein 2, breast cancer-resistant protein and the organic anion transporters, appear to serve as the gate keeper when there is an excess capacity to metabolise the compounds. These efflux transporters may also act as the facilitator of metabolism when there is a product/metabolite inhibition. For polyphenols, these coupled processes enable a duo recycling scheme of enteric and enterohepatic recycling, which allows the polyphenols to be reabsorbed and results in longer than expected apparent plasma half-lifes for these compounds and their conjugates. Because the vast majority of polyphenols in plasma are hydrophilic conjugates, more research is needed to determine if the metabolites are active or reactive, which will help explain their mechanism of actions.

Prebiotics, probiotics, and synbiotics affect mineral absorption, bone mineral content, and bone structure

Several studies in animals and humans have shown positive effects of nondigestible oligosaccharides (NDO) on mineral absorption and metabolism and bone composition and architecture. These include inulin, oligofructose, fructooligosaccharides, galactooligosaccharides, soybean oligosaccharide, and also resistant starches, sugar alcohols, and difructose anhydride. A positive outcome of dietary prebiotics is promoted by a high dietary calcium content up to a threshold level and an optimum amount and composition of supplemented prebiotics. There might be an optimum composition of fructooligosaccharides with different chain lengths (synergy products). The efficacy of dietary prebiotics depends on chronological age, physiological age, menopausal status, and calcium absorption capacity. There is evidence for an independent probiotic effect on facilitating mineral absorption. Synbiotics, i.e., a combination of probiotics and prebiotics, can induce additional effects. Whether a low content of habitual NDO would augment the effect of dietary prebiotics or synbiotics remains to be studied. The underlying mechanisms are manifold: increased solubility of minerals because of increased bacterial production of short-chain fatty acids, which is promoted by the greater supply of substrate; an enlargement of the absorption surface by promoting proliferation of enterocytes mediated by bacterial fermentation products, predominantly lactate and butyrate; increased expression of calcium-binding proteins; improvement of gut health; degradation of mineral complexing phytic acid; release of bone-modulating factors such as phytoestrogens from foods; stabilization of the intestinal flora and ecology, also in the presence of antibiotics; stabilization of the intestinal mucus; and impact of modulating growth factors such as polyamines. In conclusion, prebiotics are the most promising but also best investigated substances with respect to a bone-health-promoting potential, compared with probiotics and synbiotics. The results are more prominent in animal models, where more studies have been performed, than in human studies, where experimental conditions are more difficult to control.

Frequency of soy food consumption and serum isoflavone concentrations among Chinese women in Shanghai

Objective:

The food-frequency questionnaire (FFQ) can be an efficient tool to evaluate dietary intake in large, population-based studies, especially for specific foods. The objective of this study was to validate the assessment of soy and isoflavone (daidzein and genistein) intakes, measured by an FFQ, by comparing intakes with serum isoflavone concentrations.

Design and setting:

Soy and isoflavone intakes and serum isoflavone concentrations were determined as part of a case–control study of dietary factors and risks of benign breast disease and breast cancer. The FFQ, administered during an in-person interview, included six soy-specific line items. Blood was drawn within one week of FFQ completion.

Subjects:

In total, 1823 women living in Shanghai, People's Republic of China.

Results:

In this population, soybean milk, fresh bean curd and other bean foods were eaten once per week, and fermented bean curd, fried bean curd puff and soybeans were eaten less than once per week. A significant linear trend (P > 0.01) in serum isoflavone concentrations across increasing categories of soy and isoflavone intakes was observed, indicating that soy and isoflavone intakes, measured by the FFQ, well distinguished serum isoflavone concentrations. Linear trends were also observed in both case and control groups in stratified analyses, suggesting little differential bias by case–control status.

Conclusions:

The results suggest that the FFQ provides a useful marker of soy food consumption and isoflavone exposure in this population.

Validation study of OECD rodent uterotrophic assay for the assessment of estrogenic activity in Sprague-Dawley immature female rats

The Organization for Economic Cooperation and Development (OECD) is developing a screening and testing method to identify estrogenic/antiestrogenic compounds. Based on these demands, phase 1 study for OECD uterotrophic assay was undertaken. The OECD is in the process of validating the assay results from international participating laboratories, which carried out this study with established environmental estrogenic compounds using designed protocols. The aim of this study was to provide data for validating the OECD uterotrophic assay using Sprague-Dawley immature female rats when testing with weak or partial estrogenic compounds. Ethinyl estradiol (EE) at 0.3 or 1 microg/kg/d, a positive control used in the present study, significantly increased both uterine wet and blotted weights. In the case of weak estrogenic compounds, the uterine wet weights were significantly increased by bisphenol A (BPA) at 300 mg/kg/d, nonylphenol (NP) at 80 mg/kg/d, genistein (GN) at 35 mg/kg/d, and methoxychlor (MXC) at 500 mg/kg/d. In addition, the increase in uterine blotted weights also showed a similar pattern to that of uterine wet weights. However, both 1,1,1-trichloro-2,2-bis(p-chlorphenyl)ethane (o,p-DDT) and dibutyl phthalate (DBP) did not affect uterus (wet and blotted) weights at doses of 100 and 500 mg/kg/d. These results suggest that the increase in uterine weights should be considered useful as a sensitive endpoint for detecting weak estrogenic compounds in 3-d rodent uterotrophic assay. However, further combination studies using surrogate biomarkers may be needed to improve the sensitivity of this assay for the detection of weak estrogenic compounds, such as o,p-DDT.