phytoestrogens/insoluble fibers and colonic estrogen receptor β: randomized, double-blind, placebo-controlled study

AIM:To assess the safety and effect of the supplementation of a patented blend of dietary phytoestrogens and insoluble fibers on estrogen receptor (ER)-β and biological parameters in sporadic colonic adenomas. METHODS:A randomized, double-blind placebo-controlled trial was performed. Patients scheduled to undergo surveillance colonoscopy for previous sporadic colonic adenomas were identified, and 60 eligible patients were randomized to placebo or active dietary intervention (ADI) twice a day, for 60 d before surveillance colonoscopy. ADI was a mixture of 175 mg milk thistle extract, 20 mg secoisolariciresinol and 750 mg oat fiber extract. ER-β and ER-α expression, apoptosis and proliferation (Ki-67 LI) were assessed in colon samples. RESULTS:No adverse event related to ADI was recorded. ADI administration showed a significant increases in ER-β protein (0.822 ± 0.08 vs 0.768 ± 0.10, P = 0.04) and a general trend to an increase in ER-β LI (39.222 ± 2.69vs 37.708 ± 5.31,P = 0.06), ER-β/ER-α LI ratio (6.564 ± 10.04 vs 2.437 ± 1.53, P = 0.06), terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (35.592 ± 14.97 vs 31.541 ± 11.54, P = 0.07) and Ki-67 (53.923 ± 20.91 vs 44.833 ± 10.38, P = 0.07) approximating statistical significance. A significant increase of ER-β protein (0.805 ± 0.13 vs 0.773 ± 0.13,P = 0.04), mRNA (2.278 ± 1.19vs 1.105 ± 1.07, P < 0.02) and LI (47.533 ± 15.47 vs 34.875 ± 16.67,P < 0.05) and a decrease of ER-α protein (0.423 ± 0.06vs 0.532 ± 0.11,P < 0.02) as well as a trend to increase of ER-β/ER-α protein in ADI vs placebo group were observed in patients without polyps (1.734 ± 0.20 vs 1.571 ± 0.42, P = 0.07). CONCLUSION:The role of ER-β on the control of apoptosis, and its amenability to dietary intervention, are supported in our study.

Xenoestrogens challenge 17β-estradiol protective effects in colon cancer

Several epidemiological,cellular,and molecular studies demonstrate the role of environmental chemicals with endocrine disrupting activities,typical of Westernized societies,in the pathogenesis of numerous diseases including cancer.Nonetheless this information,the design and execution of studies on endocrine disruptors are not yet cognizant that the specific actions of individual hormones often change with development and ageing,they may be different in males and females and may be mediated by different receptors isoforms expressed in different tissues or at different life stages.These statements are particularly true when assessing the hazard of endocrine disruptors against 17β-estradiol(E2)actions in that this hormone is crucial determinant of sexrelated differences in anatomical,physiological,and behavioral traits which characterize male and female physiology.Moreover,E2 is also involved in carcinogenesis.The oncogenic effects of E2 have been investigated extensively in breast and ovarian cancers where hormone-receptor modulators are now an integral part of targeted treatment.Little is known about the E2preventive signalling in colorectal cancer,although this disease is more common in men than women,the difference being more striking amongst pre-menopausal women and age-matched men.This review aims to dissect the role and action mechanisms of E2 in colorectal cancer evaluating the ability of estrogen disruptors(i.e.,xenoestrogens)in impair these E2 actions.Data discussed here lead to define the possible role of xenoestrogens in the impairment and/or activation of E2signals important for colorectal cancer prevention.

Estrogens and the regulation of glucose metabolism

The main estrogens:estradiol,estrone,and their acyl-esters have been studied essentially related to their classical estrogenic and pharmacologic functions.However,their main effect in the body is probably the sustained control of core energy metabolism.Estrogen nuclear and membrane receptors show an extraordinary flexibility in the modulation of metabolic responses,and largely explain gender and age differences in energy metabolism:part of these mechanisms is already sufficiently known to justify both.With regard to energy,the estrogen molecular species act essentially through four key functions:(1)Facilitation of insulin secretion and control of glucose availability;(2)Modulation of energy partition,favoring the use of lipid as the main energy substrate when more available than carbohydrates;(3)Functional protection through antioxidant mechanisms;and(4)Central effects(largely through neural modulation)on whole body energy management.Analyzing the different actions of estrone,estradiol and their acyl esters,a tentative classification based on structure/effects has been postulated.Either separately or as a group,estrogens provide a comprehensive explanation that not all their quite diverse actions are related solely to specific molecules.As a group,they constitute a powerful synergic action complex.In consequence,estrogens may be considered wardens of energy homeostasis.

Biodegradation of Natural Estrogens by Biofilms from Biological Activated Carbon: Effect of Temperature

In order to obtain information on the biodegradation potential of biofilms involved in the removal of natural estrogens by biological activated carbon (BAC) columns, batch degradation of estrone (E1) and 17β-estradiol (E2) at temperature of 5℃, 20℃ and 35℃ by biofilms from four BAC columns (packed with activated carbon of particle size ranging from 0.5 - 0.59 mm and 1.0 - 1.19 mm into two bed depths) was studied. The results indicated that E2 was degraded faster by than E1 at all three temperatures and with the increasing of temperature, the amount of E1 converted from E2 increased. By fitting observed concentration data with a first-order rate expression, the bio-mass based degradation rate constants (kVSS) for E1 and E2 under all experimental conditions were estimated and linear relationship between lnkVSS and 1/T (T = absolute temperature) was demonstrated, resulting that with the increasing of the experimental temperature, degradation rate of biofilms for both E1 and E2 increased, and the increasing rate for E2 was higher than that for E1.

Simultaneous Determination of Four Estrogens in Compost Based on Ultrasonic Solvent Extraction, Solid-Phase Extraction Clean-Up and Analysis by UHPLC-MS/MS

A rapid, cost effective and reliable analytical method was developed and validated for the simultaneous determination of four estrogens (17 β-estradiol, 17 α-ethinylestradiol, estrone, and estriol) in compost samples from the biodegradation of biological infectious hazardous wastes. Ultrasonic solvent extraction, using methanol as extraction solvent, coupled with SPE clean-up, using cartridges HLB 60 mg - 6 ml Supelco® and acetonitrile for reconstitution of eluents, was used for the simultaneous extraction of the four estrogens. Mean recoveries in the range of 98% - 107% were obtained. All compounds were separated in a single gradient run by UHPLC KinetexTM 2.6 μm XB-C18 100 ÅLC (50 × 4.6 mm) column. Analytes were detected via multiple reaction monitoring (MRM) using an AB SCIEX API-5000TM triple quadrupole (Applied Biosystems/MDS SCIEX) with electrospray ionization in negative mode. Isocratic mobile phase of Water:ACN (50:50) resulted to be the optimum. Limits of detection and quantification were on the order of 0.66 ng·g-1 and 2 ng·g-1 for all the estrogens. These limits were lower than most of the values reported in the literature for similar matrices. Suitable level of linearity, good repeatability and reproducibility with coefficients of variation is lower than 11.7%, 6.8% and 8.3%, respectively.

Removal characteristics of steroid estrogens in trickling filters

The discharge of steroid estroens from sewage treatment works (STW) is to be regulated by Environmental Quality Standard in the UK,thus requiring the understanding of removal characteristics of steroid estroens in trickling filters to benefit UK water industry with trickling filters used in 75% STWs. Two pilot-scale trickling filters were operated in parallel to treat synthetic sewage spiked with oestrone (E1),oestradiol (E2) and 17α-ethinyl oestradiol (EE2) at environmentally related concentrations. Control experiments show that biodegradation is the dominant removal mechanism although adsorption onto biofilm solids prior to biodegradation would be part of the overall mechanisms of estrogen removal. Approximately 44.7%-58.9% is removed by the pilot trickling filter normally operated,whilst the 1:1 recirculation increases 29.0%-32.2% estrogen removals by improved wetting rate and hydraulic retention time supported by tracer experiment with lithium chloride. Extra feed solids with 32.0% higher suspended solids levels inhibited estrogen removals by 10.8%-34.4% rather than helping bridge adsorption to the biofilm,and the change of particle characteristics with higher adsorption potency would benefit the removal.

Voltammetric Determination of Estrogens Based on the Enhancement Effect of Surfactant at Carbon Paste Electrode

Highly sensitive voltammetric method for the determination of estrogens, based on the enhancement effect of cetyltrimethylammonium bromide (CTAB) has been described. In the presence of CTAB, the oxidation peak currents of estrogens (estradiol, estrone, estriol, estradiol valerate and diethylstilbestrol) at the carbon paste electrode (CPE) increased significantly after open circuit accumulation. The peak current was proportional to the concentration of estradiol over the range from 5×10 -9 to 2.5×10 -6 mol\5L -1 . The detection limit was 8×10 -10 mol\5L -1 at 6 min of accumulation. The total amounts of estrogens in the blood serums were determined and the average recovery was 104.92%. Under the conditions used, the electrode process of estradiol was examined and the mechanism for peak current enhancement was also discussed.

Effects of menopausal hormone therapy-based on the role of estrogens,progestogens,and their metabolites in proliferation of breast cancer cells

Menopausal hormone therapy(MHT)has been widely used for the clinical treatment of symptoms associated with menopause in women.However,the exact nature of the relationship between MHT and the increased risk of breast cancer has not been fully elucidated.The results of the Women’s Health Initiative’s randomized controlled clinical studies showed that estrogen monotherapy was associated with a lower incidence of breast cancer as compared to estrogen-progesterone combined therapy,with an elevated risk of breast cancer.The evidence currently available from randomized trials and observational studies is based on data from different populations,drug formulations,and routes of administration.Even though the risks of MHT and breast cancer have received a great deal of attention,information regarding the unpredictable toxicological risks of estrogen and progestogen metabolism needs to be further analyzed.Furthermore,the diversity and complexity of the metabolic pathways of estrogen and different progestogens as well as the association of the different estrogen and progestogen metabolites with the increased risk of breast cancer need to be adequately studied.Therefore,this review aimed to describe the biological effects of estrogen,progesterone,and their metabolites on the proliferation of breast cancer cells,based on relevant basic research and clinical trials,to improve our understanding of the biological functions of estrogen and progestogen as well as the safety of MHT.

Major royal-jelly proteins intake modulates immune functions and gut microbiota in mice

In this study,we investigated the effects of major royal jelly proteins(MRJPs)on the estrogen,gut microbiota,and immunological responses in mice.Mice given 250 or 500 mg/kg,not 125 mg/kg of MRJPs,enhanced the proliferation of splenocytes in response to mitogens.The splenocytes and mesenteric lymphocytes activated by T-cell mitogens(Con A and anti-CD3/CD28 antibodies)released high levels of IL-2 but low levels of IFN-γand IL-17A.The release of IL-4 was unaffected by MRJPs.Additionally,splenocytes and mesenteric lymphocytes activated by LPS were prevented by MRJPs at the same dose as that required for producing IL-1βand IL-6,two pro-inflammatory cytokines.The production of IL-1β,IL-6,and IFN-γwas negatively associated with estrogen levels,which were higher in the MRJP-treated animals than in the control group.Analysis of the gut microbiota revealed that feeding mice 250 mg/kg of MRJPs maintained the stability of the natural intestinal microflora of mice.Additionally,the LEf Se analysis identified biomarkers in the MRJP-treated mice,including Prevotella,Bacillales,Enterobacteriales,Gammaproteobacteria,Candidatus_Arthromitus,and Shigella.Our results showed that MRJPs are important components of royal jelly that modulate host immunity and hormone levels and help maintain gut microbiota stability.

Gut microbiota and female health

The gut microbiota is recognized as an endocrine organ with the capacity to influence distant organs and associated biological pathways.Recent advan-cements underscore the critical role of gut microbial homeostasis in female health;with dysbiosis potentially leading to diseases among women such as polycystic ovarian syndrome,endometriosis,breast cancer,cervical cancer,and ovarian cancer etc.Despite this,there has been limited discussion on the underlying mechanisms.This editorial explores the three potential mechanisms through which gut microbiota dysbiosis may impact the development of diseases among women,namely,the immune system,the gut microbiota-estrogen axis,and the metabolite pathway.We focused on approaches for treating diseases in women by addressing gut microbiota imbalances through probiotics,prebiotics supple-mentation,and fecal microbiota transplantation(FMT).Future studies should focus on determining the molecular mechanisms underlying associations between dysbiosis of gut microbiota and female diseases to realize precision medicine,with FMT emerging as a promising intervention.

Does local vaginal estrogen after tension-free transobturator vaginal tape reduce overactive bladder symptoms in postmenopausal women? A prospective randomized, controlled study

Objective:We aimed to evaluate the efficacy of topical estrogen after transvaginal tension-free vaginal tape-obturator(TVT-O)in the treatment of de novo overactive bladder symptoms that appear after surgery.Methods:This is a prospective randomized controlled study performed in the Urology and Gynecology Departments,Kasr Al Ainy Hospital,Cairo University,Cairo,Egypt.Two hundred and ten postmenopausal females presenting during the period between January 2017 and November 2020 with stress urinary incontinence were included in the study.Patients were divided into two groups,105 patients in Group A(treatment group)and 105 patients in Group B(control group).Patients in Group A underwent transvaginal TVT-O followed by local vaginal estrogen treatment for 6 months,while patients in Group B underwent transvaginal TVT-O only.The study included any postmenopausal female with urodynamic stress urinary incontinence.All patients had to fulfill a 3-day bladder diary,overactive bladder symptoms score,urine analysis,urodynamic study,and post-voiding residual urine measurement by abdominal ultrasound preoperatively and at 3-month and 6-month follow-ups.Results:At 6-month follow-up,daytime frequency was reduced to 8%in Group A(increased to 21%in Group B)with a statistically significant difference between both groups(p=0.009).At 6-month follow-up,nocturia was 8%in Group A(11%in Group B)with no statistically significant difference between both groups(p=0.469).There was a statistically significant difference between both groups as regards to urinary urgency at 6-month follow-up(p=0.024).There was a statistically significant difference in postoperative wound healing events as regards to cure,hyperemia,gapping,and wound infection 1 week after intervention between both groups(p=0.008).No local or systemic side-effects were reported from local estrogen use.Conclusion:Local vaginal estrogen treatment given to postmenopausal patients after midurethral sling procedures can reduce the symptoms of daytime frequency and urinary urgency.Long-term follow-up is needed.

Engineering of ovarian tissue for ovarian dysfunctions:A review

This review explores tissue engineering as a potential solution for reproductive health issues in women caused by genetic or acquired diseases,such as premature ovarian failure or oophorectomy.The loss of ovarian function can lead to infertility,osteoporosis,and cardiovascular disease.Hormone replacement therapy is a common treatment,but it has limitations and risks.The review focuses on two main approaches in tissue engineering:scaffold-based(3D printing,electrospinning,decellularization)and scaffold-free(stem cell transplantation,organoid cultivation).Both approaches show promise in preclinical studies for creating functional ovarian tissue.Challenges include vascularization,innervation,long-term function,and safety.Despite these challenges,tissue engineering offers a potential avenue for restoring fertility and hormone balance in women with ovarian dysfunction.

DNA interstrand cross-link induced by estrogens as well as their complete and synergic carcinogenesis

The estrogens show negative activity in Ames test, but estrodiol and diethylstilbestrol in estrogens both are carcinogens based upon animal experiments and epidemiological investigation. It is concluded from the di-region theory, a mechanism conception put forward by one of the present authors, that the carcinogenesis of estrogens is switched on by the covalent cross-link between complementary DNA bases induced by them. We verified for the first time by the DNA alkaline elution method that both estrodiol and diethylstilbestrol cause covalent cross-link between DNA-protein and DNA interstrands after metabolic activation with dosage correlation, but neither the non-carcinogens cholesterol nor pyrene can lead to these sorts of cross-link in the same condition. It has been known that there is a synergetic effect between estrogen and pollution of polycyclic aromatic hydrocarbons. Although non-carcinogenic pyrene alone cannot induce cross-link, its addition with equal molar quantity to estrodiol culture

Bidirectional regulation of angiogenesis by phytoestrogens through estrogen receptor-mediated signaling networks

Sex hormone estrogen is one of the most active intrinsic angiogenesis regulators; its therapeutic use has been limited due to its carcinogenic potential. Plant-derived phytoestrogens are attractive alternatives, but reports on their angiogenic activities often lack in-depth analysis and sometimes are controversial. Herein, we report a data-mining study with the existing literature, using IPA system to classify and characterize phytoestrogens based on their angiogenic properties and pharmacological consequences. We found that pro-angiogenic phytoestrogens functioned predominantly as cardiovascular protectors whereas anti-angiogenic phytoestrogens played a role in cancer prevention and therapy. This bidirectional regulation were shown to be target-selective and, for the most part, estrogen-receptor-dependent. The transactivation properties of ERα and ERβ by phytoestrogens were examined in the context of angiogenesis-related gene transcription. ERα and ERβ were shown to signal in opposite ways when complexed with the phytoestrogen for bidirectional regulation of angiogenesis. With ERα, phytoestrogen activated or inhibited transcription of some angiogenesis-related genes, resulting in the promotion of angiogenesis, whereas, with ERβ, phytoestrogen regulated transcription of angiogenesis-related genes, resulting in inhibition of angiogenesis. Therefore, the selectivity of phytoestrogen to ERα and ERβ may be critical in the balance of pro- or anti-angiogenesis process.

Roles of estrogens on myeloid-derived suppressor cells in cancer and autoimmune diseases

As a steroid hormone,estrogen has been extensively investigated in various physiological and pathological functions and in carcinogenesis.We previously demonstrated that estrogen promotes the secretion of MICA/B through ADAM17,which helps lung cancer cells evade NKG2D-mediated immune surveillance.1 Estrogen receptor α(ER α)and ERβ are two high-affinity nuclear receptors of estrogen that promote cancer by activating multiple growth factors and inhibiting tumorsuppressor genes.2 Anti-estrogen therapy targeting the ER has been successfully used to treat ER-positive breast cancers.ER antagonists have been widely accepted in clinical practice as an effective treatment for breast tumors and a subset of ovarian cancers.3 However,for some ovarian cancer patients,anti-estrogen therapy is not suitable.Most studies have exclusively focused on ER pathways and have ignored the interaction between estrogens and other immune cells in the tumor microenvironment.

Medical applications of phytoestrogens from the Thai herb Pueraria mirifica

Pueraria mirifica Airy Shaw et Suvatabandhu is a medicinal plant endemic to Thailand.It has been used in Thai folklore medicine for its rejuvenating qualities in aged women and men for nearly one hundred years.Indeed,it has been claimed that P.mirifica contains active phytoestrogens(plant substances with estrogen-like activity).Using high performance liquid chromatography,at least 17 phytoestrogens,mainly isoflavones,have been isolated.Thus,fairly considerable scientific researches,both in vitro in cell lines and in vivo in various species of animals including humans,have been conducted to date to address its estrogenic activity on the reproductive organs,bones,cardiovascular diseases and other climacteric related symptoms.The antioxidative capacity and antiproliferative effect on tumor cell lines have also been assessed.In general,P.mirifica could be applicable for preventing,or as a therapeutic for,the symptoms related to estrogen deficiency in menopausal women as well as in andropausal men.However,the optimal doses for each desirable effect and the balance to avoid undesired side effects need to be calculated before use.

Effects of curcumin on uterine leiomyoma in a rat model by inhibiting β-catenin/Wnt signaling pathway

Background:Women with uterine leiomyomas may suffer severe symptoms.To avoid risks of side effects,it is necessary to develop an optimal agent to shrink leiomyomas with fewer side effects and a lower recurrence rate.Curcumin may have a lower side effect in uterine leiomyoma treatment.Methods:We established the estrogen-and-progesterone-induced murine model of uterine leiomyoma.Next,we determined the expression of related genes of the β-catenin/Wnt signaling pathway by western blot,reverse transcription-polymerase chain reaction,and immunohistochemistry.We also noticed the morphological changes in uterine tissues by hematoxylin-eosin staining.Results:Curcumin plays an important role in Wnt/β-catenin signaling pathway-related expression including β-catenin,adenomatous polyposis coli,glycogen synthase kinase-3β,Wnt-11,and serum hormone concentrations.Conclusions:Curcumin could the down-regulation of serum hormone concentrations and inhibition of the β-catenin/Wnt signaling pathway in the treatment of uterine leiomyoma.

Sex-biased autophagy as a potential mechanism mediating sex differences in ischemic stroke outcome

Stroke is the second leading cause of death and a major cause of disability worldwide,and biological sex is an important determining factor in stroke incidence and pathology.From childhood through adulthood,men have a higher incidence of stroke compared with women.Abundant research has confirmed the beneficial effects of estrogen in experimental ischemic stroke but genetic factors such as the X-chromosome complement can also play an important role in determining sex differences in stroke.Autophagy is a self-degrading cellular process orchestrated by multiple core proteins,which leads to the engulfment of cytoplasmic material and degradation of cargo after autophagy vesicles fuse with lysosomes or endosomes.The levels and the activity of components of these signaling pathways and of autophagy-related proteins can be altered during ischemic insults.Ischemic stroke activates autophagy,however,whether inhibiting autophagy after stroke is beneficial in the brain is still under a debate.Autophagy is a potential mechanism that may contribute to differences in stroke progression between the sexes.Furthermore,the effects of manipulating autophagy may also differ between the sexes.Mechanisms that regulate autophagy in a sex-dependent manner in ischemic stroke remain unexplored.In this review,we summarize clinical and pre-clinical evidence for sex differences in stroke.We briefly introduce the autophagy process and summarize the effects of gonadal hormones in autophagy in the brain and discuss X-linked genes that could potentially regulate brain autophagy.Finally,we review pre-clinical studies that address the mechanisms that could mediate sex differences in brain autophagy after stroke.

月经周期中免疫球蛋白G N-糖基化的周期性变化

Immunoglobulin G(IgG)is the most abundant plasma glycoprotein and a prominent humoral immune mediator.Glycan composition affects the affinity of IgG to ligands and consequent immune responses.The modification of IgG N-glycosylation is considered to be one of the various mechanisms by which sex hormones modulate the immune system.Although the menstrual cycle is the central sex hormonerelated physiological process in most women of reproductive age,IgG N-glycosylation dynamics during the menstrual cycle have not yet been investigated.To fill this gap,we profiled the plasma IgG Nglycans of 70 healthy premenopausal women at 12 time points during their menstrual cycles(every 7 days for 3 months)using hydrophilic interaction ultra-performance liquid chromatography(HILIC-UPLC).We observed cyclic periodic changes in the N-glycosylation of IgG in association with the menstrual cycle phase and sex hormone concentration in plasma.On the integrated cohort level,the modeled average menstrual cycle effect on the abundance of IgG N-glycosylation traits was low for each trait,with the highest being 1.1%for agalactosylated N-glycans.However,intrapersonal changes were relatively high in some cases;for example,the largest difference between the minimum and maximum values during the menstrual cycle was up to 21%for sialylated N-glycans.Across all measurements,the menstrual cycle phase could explain up to 0.72%of the variation in the abundance of a single IgG glycosylation trait of monogalactosylation.In contrast,up to 99%of the variation in the abundance of digalactosylation could be attributed to interpersonal differences in IgG N-glycosylation.In conclusion,the average extent of changes in the IgG N-glycopattern that occur during the menstrual cycle is small;thus,the IgG N-glycoprofiling of women in large sample-size studies can be performed regardless of menstrual cycle phase.

Effects of a glyphosate-based herbicide on the oestrous cycle of rats

Objective:To determine the effects of a glyphosate-based herbicide on the oestrous cycle of rats.Methods:Fifteen adult Wistar rats were randomly divided into three groups.Group A served as the control group,while groups B and C received 250 and 500 mg/kg of glyphosate-based herbicide orally for five oestrous cycles,respectively.Stages of oestrous cycle,oestrous cycle index,length of cycle,oestrous cycle ratio,serum estradiol and progesterone levels were determined.Results:The proestrus and oestrus stages of the glyphosate-based herbicide groups increased significantly(P<0.05),although proestrus in group C was not significantly different from the control group.There was a significant decrease in the metestrus and diestrus of the glyphosate-based herbicide groups(P<0.05).The oestrous cycle index of the glyphosate-based herbicide treated groups was altered;this was characterized by an increase in the oestrous index and a decrease in the metestrus and diestrus indexes.The proestrus index of group B increased,while that of group C decreased.The length of the cycle of the glyphosate-based herbicide groups significantly decreased from the 1st and 3rd week till the end of the study in groups B and C,respectively(P<0.05).There was a significant increase in the oestrous cycle ratio of the glyphosate-based herbicide groups compared to the control group(P<0.05).Though the estradiol and progesterone levels of the glyphosate-based herbicide groups increased and decreased,respectively,they were not significantly different from the control group.Conclusions:Glyphosate-based herbicide at the doses of 250 and 500 mg/kg can alter the pattern of the oestrous cycle in rats.