RESUMO
Bisphenol-A (BPA), an estrogenic endocrine disrupting chemical, significantly impacts numerous diseases and abnormalities in mammals. Estrogens are known to play an important role in the biology of the prostate; however, little is known about the role of bisphenols in the etiology of prostate pathologies, including benign prostate hyperplasia (BPH) and associated lower urinary tract dysfunction (LUTD). Bisphenol-F (BPF) and bisphenol-S (BPS) are analogs often used as substitutes for BPA; they are both reported to have in vitro and in vivo estrogenic effects similar to or more potent than BPA. The objective of this study was to assess the role of these bisphenols in the development of LUTD in adult male mice. In adult mice exposed to BPA, BPS or BPF, we examined urinary tract histopathology and physiological events associated with urinary dysfunction. Mice treated with bisphenols displayed increased bladder (p < 0.005) and prostate (p < 0.0001) mass, and there was an increased number of prostatic ducts in the prostatic urethra (p < 0.05) and decreased size of the urethra lumen (p < 0.05) compared to negative controls. After two months of bisphenol exposure, mice displayed notable differences in cystometric tracings compared to controls, consistent with LUTD. Treatment of male mice with all bisphenols also induced voiding dysfunction manifested by detrusor instability and histologic changes in the prostatic urethra of male rodents, consistent with LUTD. Our results implicate BPA and its replacements in the development and progression LUTD in mice and provide insights into the development and progression of BPH/LUTS in men.
Assuntos
Compostos Benzidrílicos/toxicidade , Estrogênios não Esteroides/toxicidade , Fenóis/toxicidade , Hiperplasia Prostática/induzido quimicamente , Doenças Urológicas/induzido quimicamente , Animais , Compostos Benzidrílicos/sangue , Compostos Benzidrílicos/química , Estrogênios não Esteroides/sangue , Estrogênios não Esteroides/química , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fenóis/sangue , Fenóis/química , Hiperplasia Prostática/sangue , Hiperplasia Prostática/patologia , Doenças Urológicas/sangue , Doenças Urológicas/patologiaRESUMO
Mice produce litters containing many pups, and the female fetuses that develop between male fetuses have significantly higher concentrations of the male sex steroid testosterone in both their blood and amniotic fluid than do females that develop between other female fetuses. These two types of females differ during later life in many sexually related characteristics. Thus, individual variation in sexual characteristics of adult female mice may be traceable to differential exposure to testosterone during prenatal development because of intrauterine proximity to male fetuses.
Assuntos
Líquido Amniótico/metabolismo , Sangue Fetal/metabolismo , Camundongos/embriologia , Diferenciação Sexual , Comportamento Sexual Animal/fisiologia , Testosterona/sangue , Fatores Etários , Animais , Estradiol/sangue , Estro , Feminino , Masculino , Gravidez , Progesterona/sangue , Razão de MasculinidadeRESUMO
Infanticide has been proposed to be a pathological response to overcrowding or other forms of environmental stress and thus a maladaptive behavior. However, in male house mice this behavior is predictable and is modulated by learning. Committing infanticide can increase a male's reproductive success and in some situations may therefore be an adaptive behavior.
Assuntos
Comportamento Animal/fisiologia , Comportamento Paterno , Comportamento Sexual Animal/fisiologia , Animais , Evolução Biológica , Dominação-Subordinação , Masculino , CamundongosRESUMO
In the house mouse (Mus musculus), fetuses may develop in utero next to siblings of the same or opposite sex. The amniotic fluid of the female fetuses contains higher concentrations of estradiol than that of male fetuses. Male fetuses that developed in utero between female fetuses had higher concentrations of estradiol in their amniotic fluid than males that were located between other male fetuses during intrauterine development. They were also more sexually active as adults, less aggressive, and had smaller seminal vesicles than males that had developed between other male fetuses in utero. These findings raise the possibility that during fetal life circulating estrogens may interact with circulating androgens both in regulating the development of sex differences between males and females and in producing variation in phenotype among males and among females.
Assuntos
Agressão/efeitos dos fármacos , Estradiol/farmacologia , Feto/efeitos dos fármacos , Comportamento Sexual Animal/efeitos dos fármacos , Líquido Amniótico/análise , Animais , Estradiol/análise , Estradiol/fisiologia , Feminino , Feto/fisiologia , Humanos , Masculino , Camundongos , Progesterona/farmacologia , Ratos , Ratos Endogâmicos , Diferenciação Sexual/efeitos dos fármacos , Comportamento Sexual Animal/fisiologia , Testosterona/análise , Testosterona/farmacologiaRESUMO
Seventeen patients with adult T-cell leukemia (ATL) and 21 with tropical spastic paraparesis/human T-cell leukemia/lymphoma virus type I (HTLV-I)-associated myelopathy (TSP/HAM) were observed during a 3-yr survey (1986-1988) in some hospitals in Paris, France. Most of them were black, originating from high-HTLV-I-endemic areas (West Indies or Africa), but two cases of TSP/HAM occurred in French Caucasians. In one case, the patient acquired the virus from a transfusion during a cardiac transplantation. Most of the ATL cases were diagnosed as acute leukemia or lymphoma, with a proliferation of CD2+, CD3+, CD4+, CD8-, DR+, and CD25+ lymphoid cells. Only three cases were diagnosed as a smoldering ATL. All of the TSP/HAM cases exhibited a spastic paraparesis with a chronic and slow evolution and high HTLV-I antibody titers in serum and cerebrospinal fluid, with a high HTLV-I antibody index and specific HTLV-I immunoglobulin = oligoclonal bands. In TSP/HAM, a high percentage of DR-expressing cells (15 to 40%) was found, with a slightly elevated CD4/CD8 ratio. This was associated with the presence of 1 to 10% abnormally shaped nuclei in lymphoid cells and a polyclonal integration of HTLV-I proviruses in these peripheral blood mononuclear cells. On the contrary, a clonal integration was always found in the ATL malignant cells (leukemic, lymph node, and cutaneous infiltrate). Long-term interleukin 2-dependent T-cell lines (CD2+, CD3+, CD4+, and WT31+) with activated T-cell markers (CD25+ and DR+) producing HTLV-I were established from ATL and TSP/HAM peripheral blood mononuclear cells.
Assuntos
Leucemia-Linfoma de Células T do Adulto/epidemiologia , Paraparesia Espástica Tropical/epidemiologia , Antígenos CD/análise , Feminino , França/epidemiologia , Produtos do Gene env/análise , Anticorpos Anti-HTLV-I/análise , Humanos , Leucemia-Linfoma de Células T do Adulto/imunologia , Masculino , Paraparesia Espástica Tropical/imunologiaRESUMO
During critical periods in fetal life, there is an increased vulnerability to perturbations in endocrine function due to environmental factors. Small shifts in concentrations of hormones that regulate the differentiation of organs, such as estradiol and testosterone, can have permanent effects on morphology, enzymatic activity, and hormone receptors in tissues as well as neurobehavioral effects. These changes can lead to effects throughout life, including impacting the risk for various diseases (referred to as the Developmental Origins of Adult Health and Disease hypothesis). The intrauterine position phenomenon concerns the consequence for fetuses of randomly implanting next to embryos of the same or opposite sex. An intrauterine position next to males vs. females results in small differences in serum testosterone and estradiol during fetal life that are associated with marked effects on life history (such as lifetime fecundity) in both males and females born in litters (mice, rats, gerbils, rabbits, and swine) as well as human twins. Research with mice subsequently demonstrated that a very small experimental change in fetal serum estradiol levels altered organogenesis and caused permanent changes in organ function. Taken together, these findings led to the hypothesis that environmental chemicals that mimic or antagonize hormone action (e.g., endocrine disrupting chemicals) could also be causing harm at very low exposures (the "low dose" hypothesis) within the range of exposure of humans, domesticated animals, and wildlife. There is now extensive evidence from experimental laboratory animals, sheep, and humans that fetal exposure to very low (presumably safe) doses of the endocrine disrupting chemical bisphenol A (BPA), which exhibits estrogenic activity, can cause permanent changes that can increase the risk of a wide array of diseases. The reasons that federal regulatory agencies are ignoring the massive literature showing adverse effects of BPA and other endocrine disrupting chemicals are discussed.
Assuntos
Compostos Benzidrílicos/toxicidade , Disruptores Endócrinos/toxicidade , Meio Ambiente , Fenóis/toxicidade , Animais , Poluentes Ambientais/toxicidade , Feto/efeitos dos fármacos , Humanos , Reprodução/efeitos dos fármacosRESUMO
An unambiguous case of Sèzary syndrome associated with the presence of unusual retroviral infection markers is described. The blood smear showed 15% typical Sèzary cells but also rare atypical lymphocytes with convoluted nuclei, evocative of characteristic adult T-cell leukemia (ATL) flower cells. However, the patient did not present any clinical or biological manifestations of ATL, and human T-cell leukemia virus type 1 (HTLV-1) serology was consistently negative. After being cultured for 4 months, peripheral blood mononuclear cells (PBMC) produced typical type C retrovirus-like particles with budding forms strongly resembling HTLV-1 virions. The producer cells did not express HTLV-1-specific antigens detectable by indirect immunofluorescence (IIF). Southern blotting of uncultured PBMC DNA, submitted to digestion with the restriction enzymes PstI and SacI, and hybridized with a full genomic HTLV-1 probe, showed the presence of specific homologous sequences, absent in all of the healthy donor control PBMC DNAs. These HTLV-1-like sequences presented a restriction enzyme pattern distinct from that of the HTLV-1 prototype genome and of other HTLV-1 proviruses studied up to now. Polymerase chain reaction (PCR) with highly conserved HTLV-1 derived pol and env primers was consistently negative with the patient's DNA. All these results taken together suggest that our patient carries a retroviral agent partially homologous to, but probably different from HTLV-1. The possibility is discussed that this type of retroviral agent might be associated with a subtype of cutaneous T-cell lymphoma (CTCL) represented by a typical Sèzary syndrome with a very low percentage of ATL-like flower cells in the blood smear.
Assuntos
DNA Viral/sangue , Vírus Linfotrópico T Tipo 1 Humano/genética , Síndrome de Sézary/sangue , Síndrome de Sézary/microbiologia , Adulto , Southern Blotting , Células Cultivadas , Infecções por HTLV-I/sangue , Humanos , Leucócitos Mononucleares/microbiologia , Masculino , Microscopia Eletrônica , Reação em Cadeia da Polimerase , Síndrome de Sézary/genética , Vírion/genéticaRESUMO
Analysis was made of serum anti-HTLV-I antibodies, virus-specific proteins in peripheral blood lymphocytes (PBL) and proviruses in lymphocyte DNA of a patient with adult T-cell leukemia (ATL), Kaposi's sarcoma, and chronic myelopathy. Using Western blot and PCR (with HIV-1 specific primers), it was shown that Kaposi's sarcoma was not linked to HIV infection. Western blot analysis of serum revealed antibodies against p19, p24 and Pr 53 of HTLV-I. Examination of proteins in fresh PBL by Western blot revealed a high level of HTLV-I specific protein expression. Southern blot analysis of the patient's DNA revealed two different sites for HTLV-I provirus integration.
Assuntos
Vírus Linfotrópico T Tipo 1 Humano/metabolismo , Leucemia de Células T/microbiologia , Paraparesia Espástica Tropical/microbiologia , Sarcoma de Kaposi/microbiologia , Proteínas Virais/metabolismo , Idoso , Southern Blotting , DNA Viral/análise , Anticorpos Antideltaretrovirus/análise , Feminino , Vírus Linfotrópico T Tipo 1 Humano/genética , Humanos , Provírus/genética , Mapeamento por RestriçãoRESUMO
A survey in search of evidence for HTLV-I infection was conducted on French and Portuguese patients residing in France with a diagnosis of mycosis fungoïdes or Sezary syndrome. Methods used in this investigation included serological assays (ELISA, Western blot, particle agglutination, indirect immunofluorescence) and DNA molecular studies (Southern blot and polymerase chain reaction). Cultures of peripheral blood mononuclear cells were performed and checked by electron microscopy and reverse transcriptase assay. The results indicate that neither HTLV-I nor a closely related retrovirus are associated with mycosis fungoïde or Sezary syndrome in the cases studied.
Assuntos
Infecções por HTLV-I/diagnóstico , Micose Fungoide/microbiologia , Síndrome de Sézary/microbiologia , Neoplasias Cutâneas/microbiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores , Southern Blotting , Células Cultivadas , DNA/sangue , Feminino , França , Anticorpos Anti-HTLV-I/análise , Humanos , Leucócitos Mononucleares/química , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , PortugalRESUMO
Numerous chemicals released into the environment by man are able to disrupt the functioning of the endocrine system by binding to hormonal receptors. Exposure to estrogenic endocrine disruptors during critical periods in fetal life can alter the development of reproductive organs, the neuroendocrine system and subsequent behavior. We present a series of studies on the effects of exposure during fetal life to low, environmentally relevant doses of two pesticides, o,p'DDT and methoxychlor, and of low doses of the synthetic estrogen, diethylstilbestrol on subsequent neuro-behavioral development in house mice. The main findings can be summarized as follows: (1) Mice prenatally exposed to methoxychlor showed changes in reflex development. Exposure to a very low dose of methoxychlor appeared to produce an increased reactivity during early postnatal life. (2) Methoxychlor exposed periadolescent mice showed a decreased reaction time exploring both a novel environment and a novel object. (3) The onset of male intrasex aggression appeared to be delayed in males prenatally exposed to low doses of methoxychlor, since exposed males showed low levels of aggressive interactions during early adolescence but not after they reached adulthood. (4) The rate of depositing urine marks in a novel environment was increased in males prenatally exposed to DES, and also to o,p'DDT and methoxychlor. (5) The proportion of both males and females attacking a same-sex conspecific was increased in mice prenatally exposed to low doses of DES and, marginally, to o,p'DDT. This effect appeared to be related to a decreased latency to attack. However, males prenatally exposed to o,p'DDT displayed a decreased intensity of aggression. The possible implications of perturbing the hormonal milieu during fetal development on the modulation of developmental turnpoints and future behavioral responses are discussed.
Assuntos
Comportamento Animal/efeitos dos fármacos , Glândulas Endócrinas/efeitos dos fármacos , Efeitos Tardios da Exposição Pré-Natal , Animais , Feminino , Masculino , Camundongos , Gravidez , RatosRESUMO
The regulation of the preovulatory release of LH by steroids was examined in the mouse, a species in which ovulation is strongly influenced by priming pheromones. Ovariectomized mice were implanted with estradiol in Silastic capsules to involve negative feedback. Preovulatory-like LH surges then were induced by injections of either estradiol benzoate (EB) or progesterone. LH surges were not observed in the absence of steroid injection. LH surges always occurred at lights out on a 14-h light, 10-h dark cycle on the day after EB injection but occurred on the same day as progesterone injection. The amount of EB or progesterone injected seemed unimportant but, in either case, had to be given within a limited diurnal period of sensitivity. LH surges comparable to those of intact proestrous females were produced either by injecting both EB and progesterone or by manipulating the background dose of encapsulated estradiol. In the latter regard, when ovariectomized females were implanted with a wide range of doses of estradiol (0.1--1000 microgram/capsule), a decided window phenomenon became apparent. That is, LH surging could be induced by steroid injections only within a limited range of background doses of encapsulated estradiol. The relationship of the above findings to the pheromonal control of LH secretion and ovulation in mice is as yet unclear.
Assuntos
Estradiol/farmacologia , Hormônio Luteinizante/metabolismo , Ovulação , Progesterona/farmacologia , Animais , Castração , Escuridão , Relação Dose-Resposta a Droga , Estro , Feminino , Luz , Camundongos , Postura , Gravidez , Comportamento Sexual Animal , Fatores de TempoRESUMO
Chronic myelopathy associated with human T-lymphotropic virus type I (HTLV-I) has been described in HTLV-I endemic areas. In Paris, 167 neurologic patients were screened for HTLV-I by enzyme-linked immunosorbent, indirect immunofluorescent, and Western blot assays. Ten of the 11 patients with positive results had a chronic spastic paraparesis with IgG oligoclonal bands and elevated HTLV-I antibody index. Two of them had been born and were living in France, without HTLV-I risk factors. Evoked potentials were abnormal in the nine tested patients and brain magnetic resonance images in three of seven patients. No improvement was observed with steroid treatment. A retrovirus similar to HTLV-I was isolated in five cases at different periods of the disease. Hypotheses of limited endemic areas in western countries are discussed. Early presence and persistence of HTLV-I suggest that it is the etiologic agent.
Assuntos
Infecções por HTLV-I/complicações , Doenças da Medula Espinal/complicações , Adulto , Feminino , França , Anticorpos Anti-HTLV-I/análise , Infecções por HTLV-I/sangue , Infecções por HTLV-I/líquido cefalorraquidiano , Infecções por HTLV-I/imunologia , Infecções por HTLV-I/patologia , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Doenças da Medula Espinal/sangue , Doenças da Medula Espinal/líquido cefalorraquidiano , Doenças da Medula Espinal/diagnósticoRESUMO
The human T-cell leukemia type I (HTLV-I) virus is associated with two different diseases, adult T-cell leukemia (ATL) and tropical spastic paraparesis/HTLV-I-associated myelopathy (TSP/HAM). We have compared the viral envelopes originating from TSP/HAM and ATL patients, using the capacity of infected cells to form syncytia with receptor-expressing cells. We show that like the ATL cell lines, the TSP/HAM ones can form syncytia with a large panel of human target cells, including a variety of hematopoietic cell lines, as well as cell lines of neuroectodermal origin. None of the target cell lines tested was able to discriminate between TSP/HAM- and ATL-infected cell lines. When infected cells of TSP/HAM origin are cocultivated with cells of ATL origins, syncytia are never observed. This interference phenomenon suggests that the viruses expressed by the different cell lines utilize the same receptor.
Assuntos
Vírus Linfotrópico T Tipo 1 Humano/fisiologia , Leucemia de Células T/microbiologia , Paraparesia Espástica Tropical/microbiologia , Linfócitos T/microbiologia , Proteínas do Envelope Viral/fisiologia , Western Blotting , Linhagem Celular , Imunofluorescência , Células Gigantes , Células-Tronco Hematopoéticas/citologia , Humanos , Leucemia de Células T/patologia , Paraparesia Espástica Tropical/patologia , Receptores Virais/fisiologia , Linfócitos T/citologia , Células Tumorais CultivadasRESUMO
Significantly (p less than 0.001) decreased whole blood unconjugated serotonin levels were detected in AIDS patients as compared to patients with advanced cancers and to healthy individuals.
Assuntos
Síndrome da Imunodeficiência Adquirida/sangue , Serotonina/sangue , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias/sangueRESUMO
The structure of the ras gene family was analyzed in two human teratocarcinoma-derived cell lines, Tera I and Tera II, by DNA restriction enzyme digestion and Southern blot. We report here a ten-fold amplification of the c-Ki-ras-2 gene in these cell lines, whereas no structural alterations seem to occur either in c-Ha-ras-1 or N-ras. We also provide evidence indicating that no point mutation at codon 12, specifically recognized by Sac I, was detected. Moreover, DNA rearrangement, due to the loss of a Pvu II site located in the intervening sequences between the third and the fourth exon, has been found in both Tera I and Tera II.
Assuntos
Amplificação de Genes , Oncogenes , Teratoma/genética , Linhagem Celular , Enzimas de Restrição do DNA , Humanos , Hibridização de Ácido NucleicoRESUMO
PIP: To gather epidemiologic information on the spread of human immunodeficiency virus (HIV)-2 in Portugal, sera were collected in 1985 from 156 healthy adults currently living in Portugal but natives of Guinea Bissau, Cape Verde Islands, Saint Tome/Prince, Angola, and Mozambique and from 321 native Portuguese men and women who had close contact with local African populations. As a control, sera were collected from 102 health Portuguese with no previous contact with Africa or African natives. The enzyme-linked immunosorbent assay (ELISA) developed by Diagnostic Pasteur was used to screen for antibodies to HIV. No positive reactions were recorded in the control population. In contracts, 9 (6%) of the African natives and 7 (2%) of the contacts of Africans were HIV-positive, 6 of the positive sera were from women and 10 were from men. Significantly, 1 of the HIV-2-positive serum samples was from a native of Mozambique and 3 were from natives of Angola. This suggests that HIV-2 infection may have spread to other former Portuguese colonies, and foreign army soldiers who were at 1 time residents of Mozambique or Angola should be considered a risk group capable of spreading HIV-2 infection to other countries.^ieng
Assuntos
Anticorpos Antivirais/análise , Soropositividade para HIV , África , Ensaio de Imunoadsorção Enzimática , HIV/imunologia , Anticorpos Anti-HIV , Humanos , PortugalRESUMO
Large numbers and large quantities of endocrine-disrupting chemicals have been released into the environment since World War II. Many of these chemicals can disturb development of the endocrine system and of the organs that respond to endocrine signals in organisms indirectly exposed during prenatal and/or early postnatal life; effects of exposure during development are permanent and irreversible. The risk to the developing organism can also stem from direct exposure of the offspring after birth or hatching. In addition, transgenerational exposure can result from the exposure of the mother to a chemical at any time throughout her life before producing offspring due to persistence of endocrine-disrupting chemicals in body fat, which is mobilized during egg laying or pregnancy and lactation. Mechanisms underlying the disruption of the development of vital systems, such as the endocrine, reproductive, and immune systems, are discussed with reference to wildlife, laboratory animals, and humans.
Assuntos
Animais Selvagens , Glândulas Endócrinas/efeitos dos fármacos , Poluentes Ambientais/efeitos adversos , Animais , Dietilestilbestrol/efeitos adversos , Desenvolvimento Embrionário e Fetal/efeitos dos fármacos , Glândulas Endócrinas/crescimento & desenvolvimento , Estrogênios/efeitos adversos , Feminino , Humanos , Masculino , Modelos Biológicos , Fatores de RiscoRESUMO
F1 hybrid New Zealand Black (NZB) x New Zealand White (NZM) (NZB/NZW) mice spontaneously develop an autoimmune disease analogous to systemic lupus erythematosus (SLE). Testosterone experts a powerful suppressive effect on this disorder in adult NZB/NZW mice. A series of experiments was designed to determine if disease would also be suppressed by exposing fetal NZB/NZW mice to increased testosterone. A model was developed in which NZB dams carrying NZB/NZW fetuses were treated with testosterone in a dose adequate to masculinize the external genitalia in female fetuses. NZB/NZW mice that were derived from testosterone-treated dams and control NZB/NZW offspring were followed in a longevity study and had serial assays to assess development of SLE. Additional experiments were carried out to measure lymphocyte subsets and responses to mitogens. Results were compared with F1 hybrid offspring of C57BL/6 dams crossed with DBA/2 males, which are not autoimmune and do not develop SLE. Spleen cells from these groups were tested for Thy 1.2, CD4, CD8, and IgM receptors, and for responses to the mitogens Concanavalin A (ConA) and lipopolysaccharide. Control male NZB/NZW fetuses had unexpectedly high serum estradiol, which decreased significantly with maternal testosterone treatment. The testosterone-exposed male NZB/NZW fetuses developed into adults that lived longer than male NZB/NZW controls. Testosterone treatment of the dam was associated with elevated terminal anti-DNA levels but did not alter markers of renal diseases in adult NZB/NZW mice of either sex. Testosterone-exposed NZB/NZW females had altered T-lymphocyte subsets and testosterone-exposed males had increased response to ConA compared to controls. In male NZB/NZW fetuses whose mothers were administered testosterone, the naturally high level of circulating estradiol observed in untreated male fetuses was decreased significantly. This decrease was associated with an increase in longevity. This unique observation has important implications for fetal exposure to endocrine disruptors in the environment.
Assuntos
Doenças Autoimunes/embriologia , Doenças Autoimunes/prevenção & controle , Doenças Fetais/prevenção & controle , Cuidado Pré-Natal , Testosterona/uso terapêutico , Animais , Animais Recém-Nascidos/crescimento & desenvolvimento , Doenças Autoimunes/diagnóstico , Feminino , Doenças Fetais/diagnóstico , Longevidade , Subpopulações de Linfócitos/patologia , Masculino , Camundongos , Camundongos Endogâmicos , Mitose , Valores de ReferênciaRESUMO
We have developed a relative binding affinity-serum modified access (RBA-SMA) assay to determine the effect of serum on the access of xenoestrogens to estrogen receptors within intact cultured MCF-7 human breast cancer cells. We used this assay to predict low dose activity of two xenoestrogens in mice. In serum-free medium, bisphenol A, a component of polycarbonates and of resins used to line metal food cans, showed a lower relative binding affinity (RBA; 0.006%) than octylphenol (0.072%) and nonylphenol (0.026%), which are used as surfactants in many commercial products (all RBAs are relative to estradiol, which is equal to 100%). In 100% serum from adult men, bisphenol A showed a higher RBA (0.01%) than in serum-free medium and thus enhanced access to estrogen receptors relative to estradiol. In contrast, octylphenol showed a 22-fold decrease in RBA (0.0029%) and nonylphenol showed a 5-fold decrease in RBA (0.0039%) when measured in adult serum. This indicates that, relative to estradiol, serum had less of an inhibitory effect on the cell uptake and binding in MCF-7 cells of bisphenol A, while serum had a greater inhibitory effect on octylphenol and nonylphenol relative to estradiol. Extrapolation of these relative activities in adult serum predicted that the estrogenic bioactivity of bisphenol A would be over 500-fold greater than that of octylphenol in fetal mouse serum. Bisphenol A and octylphenol were fed to pregnant mice at 2 and 20 micrograms/kg/day. Exposure of male mouse fetuses to either dose of bisphenol A, but to neither dose of octylphenol, significantly increased their adult prostate weight relative to control males, which is consistent with the higher predicted bioactivity of bisphenol A than octylphenol in the RBA-SMA assay. In addition, our findings show for the first time that fetal exposure to environmentally relevant parts-per-billion (ppb) doses of bisphenol A, in the range currently being consumed by people, can alter the adult reproductive system in mice.