Development Of Male Reproductive System Research Articles

Suppressing male spermatogenesis-associated protein 5-like gene expression reduces vitellogenin gene expression and fecundity in Nilaparvata lugens Stål.

In our previous study with the brown planthopper (BPH), Nilaparvata lugens, triazophos (tzp) treatments led to substantial up-regulation of a male spermatogenesis-associated protein 5-like gene (NlSPATA5) compared to untreated controls. Mating with tzp-treated males significantly increased fecundity (as numbers of eggs laid), relative to females mated with untreated males. Because SPATA5 acts in mammalian sperm development and is expressed in testes, we posed the hypothesis that NlSPATA5 occurs in BPH seminal fluid and it operates in fecundity via mating. We tested the hypothesis by investigating the influence of suppressing NlSPATA5 expression in BPH males on fecundity. Reduced expression of NlSPATA5 led to decreased male accessory gland protein content and reproductive system development compared to controls. These changes in males led to prolonged pre-oviposition periods and decreased fecundity in females. For both genders, we recorded no difference in the body weight, oviposition periods, and longevity compared to controls. NlSPATA5 suppression in males also led to decreased fat body and ovarian protein content, yeast-like symbionts abundance and ovarian development as well as vitellogenin gene expression in their mating partners. We infer that increased NlSPATA5 expression may be one molecular mechanism of tzp-driven reproduction and population increases in BPH.

Hormonal modulation of catecholaminergic neurotransmission in a prenatal stress model.

Our laboratory has a long-standing interest in the effects of prenatal stress (PS) on various neurotransmitter pathways and the morphology of the developing brain as well as in behavioural aspects of the offspring. Employing a commonly used PS paradigm in which the dams were subjected to restraint stress during the last week of gestation, we observed that several of these pathways were altered in the offspring brain. In this chapter, we will summarize and discuss the results obtained with the main catecholaminergic pathways, namely dopamine (DA) and norepinephrine (NE). In our hands, PS produces an increase in dopamine D2-type receptors in limbic areas, a decreased DA release after amphetamine stimulation in prefrontal cortex (PFC) and an increase in NE release in the same area of the adult offspring brain. In addition, DA uptake is altered at prepubertal stages that persist through adulthood. However, the expression of the step-limiting enzyme of the DA synthesis, tyrosine hydroxylase (TH), is only impaired at early stages of development after PS in the neuronal bodies. At the nuclear regulation level, dopaminergic transcription factors Nurr1 and Ptx3 showed a high vulnerability to PS showing changes along the lifespan. It was striking to observe that many impairments observed in most of these pathways differed depending on whether they were tested before or after puberty indicating a particular sensitivity of the systems to variations in gonadal hormones peaks. In fact, we observed that PS induced long-term effects on the male offspring reproductive system and spermatogenesis development, particularly by inducing a long-term imbalance of circulating sexual hormone levels. Our findings suggest that PS exerts long-term effects on various neurotransmitter pathways altering the normal connectivity between brain areas. Since the developing forebrain was shown to be influenced by androgen exposure, and PS was shown to disrupt prenatal testosterone surges, our results suggest that prenatal insults might be affecting the organizational role of androgens during brain development and differentially modulating their activational role during pubertal brain maturation.

Generation of hazard indices for cumulative exposure to phthalates for use in cumulative risk assessment

Exposures to multiple chemicals may contribute to increased risk of similar adverse effects. Cumulative risk may be estimated using a hazard index (HI), the sum of individual hazard quotients (HQ, ratio of exposure to the reference value). We demonstrate the HI approach for five phthalates: di(2-ethylhexyl) phthalate (DEHP), di-n-butyl phthalate (DBP), diisobutyl phthalate (DiBP), diisononyl phthalate (DiNP), and butyl benzyl phthalate (BBP). Phthalate exposure for the US general population is estimated using urine metabolite levels from NHANES, extrapolating to ingested ‘dose’ using the creatinine correction approach. We used two sets of reference values: European Union Tolerable Daily Intakes and Denmark Environmental Protection Agency Derived No Effect Levels. We also investigated the use of an alternate reference value for DEHP, derived from a recent study on male reproductive system development. HQs and HIs were calculated for the total population ages 6years and older, as well as for men and women of approximate reproductive age (18–39years), and children (6–11years). Median HQs ranged from <0.01 for BBP, to ∼0.1 (using established values) or ∼2 (using an alternate value) for DEHP. Median HIs were <0.30 (95th percentiles just >1.0), and were driven by DEHP and DBP exposures.

Multigeneration Reproduction and Male Developmental Toxicity Studies on Atrazine in Rats

BACKGROUNDReproductive toxicity of Atrazine (ATR) was evaluated in two rat multigenerational studies. Development of male reproductive parameters was evaluated in separate studies after prenatal or postnatal exposure.METHODSIn multigenerational studies, rats received dietary concentrations of 0, 10, 50, 100 or 500 ppm ATR. In separate studies in female rats, ATR was administered by gavage at 0, 1, 5, 25 or 125 mg/kg/day during pregnancy (GD6–21) or lactation (LD2–21). Plasma testosterone concentration, testicular and epididymal weights, and sperm counts were measured in male offspring on PND70 and 170.RESULTSIn the multigenerational studies, parental systemic toxicity occurred at 500 ppm (38.7 mg/kg/day), but reproductive endpoints were unaffected. In the prenatal study, maternal toxicity and embryo-fetal mortality occurred at 125 mg/kg/day. In male offspring, testosterone levels and sperm counts were unaffected, although the percentage of abnormal sperm increased at 125 mg/kg/day (PND 70) and 25 mg/kg/day (PND170). In the postnatal study, maternal toxicity and reduced body weights of male offspring occurred at 125 mg/kg/day. Additionally, reduced testicular (PND70, PND170) and epididymal (PND70) weights and increased numbers of abnormal sperm (PND70, PND170) were seen, but no changes in plasma testosterone or sperm counts.CONCLUSIONSDietary administration of ATR did not affect rat reproduction up to a parentally toxic dose of 38.7 mg/kg/day. Some effects on male reproductive system development occurred after high dose, bolus administration to dams, but doses were much higher than expected under normal use conditions. Thus, oral RfDs for ATR would be protective for reproductive effects

Novel roles of Pkd2 in male reproductive system development

Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common inherited genetic diseases, caused by mutations in PKD1 and/ or PKD2. Infertility and reproductive tract abnormalities in male ADPKD patients are very common and have higher incidence than in the general population. In this work, we reveal novel roles of Pkd2 for male reproductive system development. Disruption of Pkd2 caused dilation of mesonephric tubules/efferent ducts, failure of epididymal coiling, and defective testicular development. Deletion of Pkd2 in the epithelia alone was sufficient to cause reproductive tract defects seen in Pkd2−/− mice, suggesting that epithelial Pkd2 plays a pivotal role for development and maintenance of the male reproductive tract. In the testis, Pkd2 also plays a role in interstitial tissue and testicular cord development. In-depth analysis of epithelial-specific knockout mice revealed that Pkd2 is critical to maintain cellular phenotype and developmental signaling in the male reproductive system. Taken together, our data for the first time reveal novel roles for Pkd2 in male reproductive system development and provide new insights in male reproductive system abnormality and infertility in ADPKD patients.

Association study between Y-chromosome haplo group and suscepti-bility to spermatogenisis impairment in Han People from Southwest China

Idiopathic azoospermia and oligospermia are one of the most important reasons for male infertility. Abnormal karyotype and azoospermia factor (AZF) microdeletion are two widely acknowledged reasons, but the most causes remain unclear. Y chromosome, as the male-specific chromosome, is closely related to the development of male reproductive system. To understand better the etiology of idiopathic azoospermia and oligospermia, we investigated the possible association between Y-haplogroup distributions and susceptibility to idiopathic azoospermia and severe oligospermia. Peripheral blood was collected from 193 men with normal reproductive history, 193 men with idiopathic azoospermia, and 72 men with idiopathic severe oligospermia. All the subjects underwent karyotyping and AZF deletion analysis to screen out those with AZF deletion and abnormal karyotype. The comparison of Y-haplogroup distribution between experimental group and control group was performed with SPSS V.18.0 software. Significant difference of Y-haplogroup distribution was observed in D1*, F*, K*, N1* and O3*(P=0.032, 0.022, 0.009, 0.009, 0.017, <0.05). The results suggest that Y chromosome haplogroup plays a important role in spermatogenic impairment.

Effect of Sialoadenectomy on the development of male reproductive organs in mice (Mus musculus).

Submandibular gland is rich source of epidermal growth factor (EGF). To investigate the role of salivary EGF on the development of male reproductive system we have performed the sialoadenectomy (removal of submandibular glands) of the 20 days old male mice and this sialoadenectomised mice was sacrificed on 45, 60 and 90th day. The testis, seminal vesicle, prostate gland, caput and cauda epididymis were dissected out for protein estimation and histological studies. It was found that the there was significant loss in the weight of these organs, protein content in the sialoadenectomised mice as compared to control. The histological structures of these organs were also changed in the sialoadenectomised mice. Keyword: Sialoadenectomy, Histology, weight, Protein

Steroid Hormone in Ageing

Copyright: © 2013 Gazi R. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Chemically steroids are similar to that of cholesterol and in most instances these hormones are synthesized from cholesterol. These are lipid soluble and consist of three cyclohexyl rings and one cyclopentyl ring combined into a single structure. Steroids are secreted by the adrenal cortex, ovaries, testis, and placenta. Aldosterone, cortisol, estrogen, and testosterone are some common steroids in the body [1]. Too much or too little secretion of steroids leads to de-arrangements in the body [2]. Estrogen promotes growth and development of female reproductive system, female breast and female secondary sexual characteristics, while testosterone promotes development of male reproductive system and male secondary sexual characteristics. Over production of adrenal androgens leads to adreno-genital syndrome among females; masculinizing effects, develops male pattern of body hair, “Hirsutism” (muscular limbs with deep voice, and small breast in females). However, excess secretion of adrenal androgens in males has no apparent effects but abundance of musculinizing effects.

Effect of antithyroid propyl thiouracil on male reproductive system development in local chicks

The aim of this experiment is to study the effects of antithyroid agent (Propylthiouracil, PTU) on domestic chicks male reproductive system. 36 local male one day old chicks were used. Chicks were distributed randomly to three groups, first group (control group) fed standard diet, while 2nd and 3 rd groups were fed diet contain 0.01 and 0.1 % of antithyroid agent (Propylthiouracil PTU) respectively, from 1 - 25 days of age. Chicks were killed at the end of 4th week in order to study the effects of PTU treatment on some male reproductive system and secondary sexual characteristic as well as some body organs. Results revealed that PTU treatment significantly decreased body weight, significantly increased right and left testis percentage and absolute weights in group treated with 0.1% PTU compared with the control group. Treatment also significantly increase comb length and height as well as in liver and heart weights.

Prolonged consumption of flaxseed flour increases the 17β-estradiol hormone without causing adverse effects on the histomorphology of Wistar rats’ penis

Consumption of foods rich in phytoestrogens such as flaxseed has increased due to its chemoprotective effects, especially those related to the cardiovascular system. The flaxseed has components that can interfere with development of male reproductive system. This study aims to investigate the possible effects of prolonged consumption of flaxseed flour on hormonal and histomorphologic penis parameters of adult Wistar rats. Rat dams were divided into two groups during lactation period: the control group that was fed with diet based on casein and the flaxseed group that was fed with diet based on casein containing 25% of flaxseed . At weaning, 10 male offspring from each group continued to receive the experimental diets until 250days old. Rats fed with diet containing flaxseed showed increased concentrations of 17β-estradiol (p=0.01) but no changes in testosterone concentrations. With regard to histomorphometric analysis of the penis, supplemented rats had lower values for the total area of the corpus spongiosum (p=0.01). All other analyzed parameters wer e similar as the control. Results showed that the use of flaxseed flour did not cause adverse effects on the penis morphology but increases the 17β-estradiol hormone, when consumed in integral form for a prolonged period.

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.

Development of male reproductive system of the blue land crab Cardisoma guanhumi Latreille, 1828 (Decapoda: Gecarcinidae)

AbstractShinozaki‐Mendes, R.A., Silva, J.R.F. and Hazin, F.H.V. 2011. Development of male reproductive system of the blue land crab Cardisoma guanhumi Latreille, 1828 (Decapoda: Gecarcinidae). —Acta Zoologica (Stockholm) 93: 390–399.In this study, the reproductive tract of the Cardisoma guanhumi was described both macroscopically and microscopically. The maturation stages of the reproductive system were defined, and the development of germ cells was described. The reproductive tract is made up of a pair of testis, a pair of vas deferentia, and a pair of ejaculatory ducts. The germ cells were classified in the order of development as spermatogonia (diameter: 10.5 ± 0.11 μm), spermatocytes (9.7 ± 0.07 μm), spermatids (initial phase: 5.5 ± 0.06 μm; final phase: 4.3 ± 0.05), and spermatozoa (SPZ) (4.0 ± 0.03 μm). The testis is made up of a germ zone, a maturation zone and collector ducts, which lead to the anterior vas deferens (AVD), containing solely SPZ. The spermatophores (SPH) start to be formed in the AVD, through the secretion of spermatophoric and protein matrices. In the median vas deferens, the SPH, already fully formed, are stored, while in the posterior vas deferens, a large production of a glycoprotein matrix is observed. Based on macroscopic and microscopic description of the male reproductive tract, three maturation stages are proposed: immature, maturing, and mature.

Perinatal exposure to parasiticide ivermectin: long-term effects on reproductive parameters of adult male rats

Ivermectin is one of the most widely used antiparasitic drugs globally. The aim of this study was to evaluate the chronic effects of perinatal exposure to ivermectin on male reproductive parameters in rats. Pregnant rats were treated daily by oral gavage with 0.4 or 1.6 mg kg−1 of ivermectin or vehicle, from gestational day 6 until post-natal day 10. In the adulthood stage, there were significant reductions in the relative testicular weight of rats exposed to the low dose and in relative prostate weight of male rats exposed to the high dose of ivermectin. Furthermore, the animals exposed to the low dose also presented an increased seminal vesicle weight compared to controls. However, neither of the ivermectin doses interfered in daily sperm production, sperm number in testis, or sexual behavior of exposed males. In conclusion, perinatal exposure to ivermectin neither altered the male reproductive system development markedly, nor produced any adverse effects on the parameters evaluated.

Functions of essential nutrition for high quality spermatogenesis

The process of sperm production is well understood, but the studies of essential nutritional elements which are necessary for successful spermatogenesis are not deeply studied as yet. Our review focuses on integrating available information of various nutritional elements involved in spermatogenesis, sperm maturation and male reproductive system development, such as Zinc, Selenium, Folate, Vitamins and others. Antioxidants protect sperm from further oxidative damage during the entire sperm production. Other nutrients assist to improve sperm quality through different ways. The important roles of macronutrients like lipids, amino acids and proteins are emphasized here. These macronutrients constitute major components of the spermatozoa. Effects of nutritional elements on the development of Sertoli cells and Leydig cells, sperm motility and semen quality, capacity of capacitation and fertilization are discussed. A review of these areas will provide researchers with a better understanding of the compulsory participation of these nutrients in male reproductive processes. This review also pointed out gaps in current studies which will require further investigations.

Toxic effects of lactational exposure to 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (TCDD) on development of male reproductive system: Involvement of antioxidants, oxidants, and p53 protein

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a potent endocrine disruptor compound and induces multiple organ dysfunctions. The effect of TCDD exposure both in adults and in utero has been well established. However, little is known about the effects of TCDD acquired through mother's milk on the development of the male reproductive system. The aim of this study was to investigate the effects and mechanisms of TCDD from lactational exposure. TCDD (1 microg/kg) was administered to C57BL/6 mouse mothers for 4 days from the day of delivery. On postnatal day 30 (PND 30) and postnatal day 60 (PND 60), body weight, body length, and anogenital distance (AGD) of male offspring were measured. The weights of the testes and epididymides were also measured. Epididymides were used for sperm counts, and testes were used to measure the activity of antioxidant enzymes (SOD, CAT, GPX, GR), the parameters of oxidative stress (hydrogen peroxide, MDA), and testosterone. In addition, expression of p53 and the proapoptotic protein, Bax, were analyzed by Western blot. TCDD exposure decreased body weight, body length, and AGD in both PND 30 and PND 60 groups compared with the control group. The activity of all antioxidant enzymes at PND 60 was decreased after TCDD treatment. TCDD treatment decreased testicular testosterone levels in both the PND 30 and PND 60 groups. The expression of p53 and Bax were also upregulated by TCDD and did not return to normal levels by PND 60. These data suggest that TCDD affects development of male offspring when the mother is exposed to TCDD during lactation. In addition, oxidative stress is a major mediator of TCDD-induced adverse effects, and p53 may play an important role in this mechanism.

Expression of the Ladybird-like homeobox 2 transcription factor in the developing mouse testis and epididymis

BackgroundHomeoproteins are a class of transcription factors that are well-known regulators of organogenesis and cell differentiation in numerous tissues, including the male reproductive system. Indeed, a handful of homeoproteins have so far been identified in the testis and epididymis where a few were shown to play important developmental roles. Through a degenerate PCR approach aimed at identifying novel homeoproteins expressed in the male reproductive system, we have detected several homeoproteins most of which had never been described before in this tissue. One of these homeoproteins is Ladybird-like homeobox 2 (Lbx2), a homeobox factor mostly known to be expressed in the nervous system.ResultsTo better define the expression profile of Lbx2 in the male reproductive system, we have performed in situ hybridization throughout testicular and epididymal development and into adulthood. Lbx2 expression was also confirmed by real time RT-PCR in those tissues and in several testicular and epididymal cell lines. In the epididymis, a highly segmented tissue, Lbx2 shows a regionalized expression profile, being more expressed in proximal segments of the caput epididymis than any other segment. In the testis, we found that Lbx2 is constitutively expressed at high levels in Sertoli cells. In interstitial cells, Lbx2 is weakly expressed during fetal and early postnatal life, highly expressed around P32-P36, and absent in adult animals. Finally, Lbx2 can also be detected in a population of germ cells in adults.ConclusionAltogether, our data suggest that the homeoprotein Lbx2 might be involved in the regulation of male reproductive system development and cell differentiation as well as in male epididymal segmentation.

In vitro assessment of transcriptional activation of the estrogen and androgen receptors of mosquitofish, Gambusia affinis affinis

Sex-steroid hormones are essential for normal reproductive activity in both sexes. Estrogens are necessary for ovarian differentiation during a critical developmental stage in many vertebrates and promote the growth and differentiation of the female reproductive system. Androgens play essential roles in the development and functioning of the vertebrate male reproductive system as well as actively supporting spermatogenesis. Importantly, recent studies suggest that androgens and estrogens have important reproductive roles in both males and females. To understand the molecular mechanisms of estrogen and androgen actions and to evaluate estrogen and androgen receptor–ligand interactions in the mosquitofish, Gambusia affinis affinis, we used degenerate primer sets and PCR techniques to isolated DNA fragments encoding estrogen receptor alpha (ERα; ESR1), ERbeta1 (ERβ1) and ERβ2 from the ovary. Full-length mosquitofish ER (mfER) cDNAs were obtained using cDNA library screening and RACE techniques. Amino acid sequences of mfERs showed over-all homology of 46% (α versus β1), 43% (α versus β2), and 52% (β1 versus β2). We applied the ERE-luciferase reporter assay system to characterize these receptors. In this transient transfection assay system using mammalian cells, the mfER proteins displayed estrogen-dependent activation of transcription. In addition to ERs, the transactivation of mosquitofish ARs (mfARs) previously isolated by our group, were examined using an androgen-responsive MMTV-luciferase assay system. Mosquitofish ARs showed androgen-dependent activation of transcription from the MMTV promoter. These data provide a basic tool allowing future studies examining the receptor–ligand interactions and endocrine disrupting mechanisms in mosquitofish and also expands our knowledge of estrogen and androgen receptor evolution.

Refolding and one-step purification of recombinant human ARA70 over-expressed in Escherichia coli

Androgen receptor (AR)-associated coregulator 70 (ARA70) is a cytoplasmic protein that has been characterized to have the ability to induce AR transcriptional activity in response to androgens and anti-androgens in prostate cancer cells. AR has been shown to have an important role in the progression of prostate cancer and in normal male reproductive system development. To elucidate the molecular mechanisms and biological relevance of ARA70 to prostrate cancer using a variety of biochemical analyses, the cDNA encoding full length ARA70 was cloned into pET21b vector. Here, we report the refolding and one-step purification of ARA70 from inclusion bodies over-expressed in Escherichia coli. The protein was purified to homogeneity, yielding ∼60 mg ARA70 from 1 L of terrific broth media. Refolding process of ARA70 was monitored using far-UV CD analysis.

Effects of Exposure to Genistein and Estradiol on Reproductive Development in Immature Male Mice Weaned from Dams Adapted to A Soy-based Commercial Diet

Genistein, a soybean-originated isoflavone, is widely consumed by humans for putative beneficial health effects but its estrogenic activity may adversely affect the development of male reproductive system. Twenty one-day-old ICR mice weaned from dams fed with a soybean-based diet throughout gestation and lactation were exposed by gavage to genistein (2.5 mg/kg b.w./day) or 17beta-estradiol (7.5 microg/kg b.w./day) for five weeks. Corn oil was used as a negative control. The animals were fed with a casein-based AIN-76A diet throughout the experimental periods. There were no significant differences in body and organ weights of mice among experimental groups. No significant differences in sperm counts and sperm motile characteristics were found between control and genistein groups. Treatment of 17beta-estradiol caused a significant decrease in prostate weight and epididymal sperm counts compared to the control (p<0.05). The levels of phospholipid hydroxide glutathione peroxidase in the testis and prostate of mice exposed to genistein or 17beta-estradiol were significantly higher than that of the control mice (p<0.05). 17beta-estradiol treatment caused degeneration and apoptosis of germ cells in the testis, depletion and degeneration in the epididymal epithelium, and hyperplasia of mucosal fold region in the prostate of mice. Genistein treatment did not cause any lesion in the testis, epididymis, and prostate. These results suggest that dietary uptake of genistein during juvenile period may not affect male reproductive development and functions.

Exposure to genistein does not adversely affect the reproductive system in adult male mice adapted to a soy-based commercial diet

Genistein, a soybean-originated isoflavone, is widely consumed by humans for putative beneficial health effects but its estrogenic activity may affect adversely the development of male reproductive system. Five-week-old ICR mice were purchased and fed with a soybean-based Purina Chow diet until 6 months of age. The animals were exposed by gavage to genistein (2.5 mg/kg/day) or 17beta-estradiol (7.5 microg/kg/day) for five weeks. Corn oil was used for the negative control. The animals were fed the casein-based AIN-76A diet throughout the experimental periods. There were no significant differences in body and organ weights of mice among experimental groups. No significant differences in sperm counts and sperm motile characteristics were found between the control and the genistein groups. Treatment of 17beta-estradiol caused a significant decrease in epididymal sperm counts compared to the control (p<0.05). The level of phospholipid hydroxide glutathione peroxidase in the epididymis of mice exposed to genistein was significantly higher than that of the control mice (p<0.05). 17beta-estradiol treatment caused a reduction of germ cells in the testis and hyperplasia of mucosal fold region in the prostate of mice. Genistein treatment did not cause any lesion in the testis, epididymis, and prostate. These results suggest that dietary uptake of genistein at adult stage of life may not affect male reproductive system and functions.