@misc{sternberg_gooding_hotchkiss_leblanc_2010, title={Environmental-endocrine control of reproductive maturation in gastropods: implications for the mechanism of tributyltin-induced imposex in prosobranchs}, volume={19}, ISSN={["1573-3017"]}, DOI={10.1007/s10646-009-0397-z}, abstractNote={Prosobranch snails have been afflicted globally by a condition whereby females develop male sex characteristics, most notably a penis. This condition, known as imposex, has been causally associated with the ubiquitous environmental contaminant tributyltin (TBT). Deduction of the mechanism by which TBT causes imposex has been hampered by the lack of understanding of the normal endocrine regulation of reproductive tract recrudescence in these organisms. We have reviewed the relevant literature on the environmental and endocrine factors that regulate reproductive tract recrudescence, sexual differentiation, and reproduction in gastropods. We provide a cohesive model for the environmental-endocrine regulation of reproduction in these organisms, and use this information to deduce a most likely mechanism by which TBT causes imposex. Photoperiod appears to be the predominant environmental cue that regulates reproductive tract recrudescence. Secondary cues include temperature and nutrition which control the timing of breeding and egg laying. Several hormone products of the central and peripheral nervous systems have been identified that contribute to recrudescence, reproductive behaviors, oocyte maturation and egg laying. Retinoic acid signaling via the retinoid X-receptor (RXR) has shown promise to be a major regulator of reproductive tract recrudescence. Furthermore, TBT has been shown to be a high affinity ligand for the RXR and the RXR ligand 9-cis retinoic acid causes imposex. We propose that TBT causes imposex through the inappropriate activation of this signaling pathway. However, uncertainties remain in our understanding of the environmental-endocrine regulation of reproduction in gastropods. Definitive elucidation of the mechanism of action of TBT awaits resolution of these uncertainties.}, number={1}, journal={ECOTOXICOLOGY}, author={Sternberg, Robin M. and Gooding, Meredith P. and Hotchkiss, Andrew K. and LeBlanc, Gerald A.}, year={2010}, month={Jan}, pages={4–23} }
 @article{ryan_hotchkiss_crofton_gray_2010, title={In utero and lactational exposure to bisphenol A, in contrast to ethinyl estradiol, does not alter sexually dimorphic behavior, puberty, fertility, and anatomy of female LE rats}, volume={114}, number={1}, journal={Toxicological Sciences}, author={Ryan, B. C. and Hotchkiss, A. K. and Crofton, K. M. and Gray, L. E.}, year={2010}, pages={133–148} }
 @article{rider_wilson_howdeshell_hotchkiss_furr_lambright_gray_2009, title={Cumulative Effects of In Utero Administration of Mixtures of "Antiandrogens" on Male Rat Reproductive Development}, volume={37}, ISSN={["1533-1601"]}, DOI={10.1177/0192623308329478}, abstractNote={ Although risk assessments are typically conducted on a chemical-by-chemical basis, the 1996 Food Quality Protection Act (FQPA) required the Environmental Protection Agency (EPA) to consider cumulative risk of chemicals that act via a common mechanism of toxicity. To this end, we are conducting studies with mixtures to provide a framework for assessing the cumulative effects of “antiandrogenic” chemicals. Rats were dosed during pregnancy with antiandrogens singly or in pairs at dosage levels equivalent to about one half of the ED50 for hypospadias or epididymal agenesis. The pairs include: AR antagonists (vinclozolin plus procymidone), phthalate esters (DBP plus BBP and DEHP plus DBP), a phthalate ester plus an AR antagonist (DBP plus procymidone), and linuron plus BBP. We predicted that each chemical by itself would induce few malformations; however, by mixing any two chemicals together, about 50% of the males would be malformed. All binary combinations produced cumulative, dose-additive effects on the androgen-dependent tissues. We also conducted a mixture study combining seven “antiandrogens” together. These chemicals elicit antiandrogenic effects at two different sites in the androgen signaling pathway (i.e., AR antagonist or inhibition of androgen synthesis). In this study, the complex mixture behaved in a dose-additive manner. Our results indicate that compounds that act by disparate mechanisms of toxicity display cumulative, dose-additive effects when present in combination. }, number={1}, journal={TOXICOLOGIC PATHOLOGY}, author={Rider, Cynthia V. and Wilson, Vickie S. and Howdeshell, Kembra L. and Hotchkiss, Andrew K. and Furr, Johnathan R. and Lambright, Christy R. and Gray, L. Earl, Jr.}, year={2009}, month={Jan}, pages={100–113} }
 @article{howdeshell_wilson_furr_lambright_rider_blystone_hotchkiss_gray_2008, title={A mixture of five phthalate esters inhibits fetal testicular testosterone production in the sprague-dawley rat in a cumulative, dose-additive manner}, volume={105}, ISSN={["1096-6080"]}, DOI={10.1093/toxsci/kfn077}, abstractNote={Phthalate diesters are chemicals to which humans are ubiquitously exposed. Exposure to certain phthalates during sexual differentiation causes reproductive tract malformations in male rats. In the fetal rat, exposure to the phthalates benzylbutyl phthalate (BBP), di(n)butyl phthalate (DBP), and diethylhexyl phthalate (DEHP) decreases testicular testosterone production and insulin-like 3 hormone mRNA levels. We characterized the dose-response effects of six individual phthalates (BBP, DBP, DEHP, diethyl phthalate [DEP], diisobutyl phthalate [DiBP], and dipentyl phthalate [DPP]) on gestation day (GD) 18 testicular testosterone production following exposure of Sprague-Dawley rats on GD 8-18. BBP, DBP, DEHP, and DiBP were equipotent (ED50 of 440 +/- 16 mg/kg/day), DPP was about threefold more potent (ED50 = 130 mg/kg/day) and DEP had no effect on fetal testosterone production. We hypothesized that coadministration of these five antiandrogenic phthalates would reduce testosterone production in a dose-additive fashion because they act via a common mode of toxicity. In a second study, dams were dosed at 100, 80, 60, 40, 20, 10, 5, or 0% of the mixture. The top dose contained 1300 mg of total phthalates/kg/day including BBP, DBP, DEHP, DiBP (300 mg/kg/day per chemical), and DPP (100 mg DPP/kg/day). This mixture ratio was selected such that each phthalate would contribute equally to the reduction in testosterone. As hypothesized, testosterone production was reduced in a dose-additive manner. Several of the individual phthalates and the mixture also induced fetal mortality, due to pregnancy loss. These data demonstrate that individual phthalates with a similar mechanism of action can elicit cumulative, dose additive effects on fetal testosterone production and pregnancy when administered as a mixture.}, number={1}, journal={TOXICOLOGICAL SCIENCES}, author={Howdeshell, Kembra L. and Wilson, Vickie S. and Furr, Johnathan and Lambright, Christy R. and Rider, Cynthia V. and Blystone, Chad R. and Hotchkiss, Andrew K. and Gray, Leon Earl, Jr.}, year={2008}, month={Sep}, pages={153–165} }
 @article{wilson_blystone_hotchkiss_rider_gray_2008, title={Diverse mechanisms of anti-androgen action: impact on male rat reproductive tract development}, volume={31}, ISSN={["1365-2605"]}, DOI={10.1111/j.1365-2605.2007.00861.x}, abstractNote={Summary}, number={2}, journal={INTERNATIONAL JOURNAL OF ANDROLOGY}, author={Wilson, Vickie S. and Blystone, Chad R. and Hotchkiss, Andrew K. and Rider, Cynthia V. and Gray, L. Earl, Jr.}, year={2008}, month={Apr}, pages={178–185} }
 @article{hotchkiss_sternberg_leblanc_2008, title={Environmental cues trigger seasonal regression of primary and accessory sex organs of the mud snail, Ilyanassa obsoleta}, volume={74}, ISSN={["0260-1230"]}, DOI={10.1093/mollus/eyn009}, abstractNote={Animals inhabiting non-tropical environments undergo seasonal changes in reproduction in order to improve their survival and chances of successful reproduction. For example, during certain periods of the year, food shortages and temperature extremes can make survival difficult. Adaptive physiological, behavioral and morphological changes are made to maintain a positive energy balance throughout the year and to ensure that offspring are born during a period when their chances of survival are maximized. Neogastropods display an annual rhythm in the seasonal re-growth of their reproductive tract and secondary sex organs. Although environmental cues likely stimulate neuro-endocrine cascades that orchestrate male and female sex organ differentiation as well as oogenesis, spermatogensis and copulatory behaviour, little is known about the specific seasonal cues or the underlying physiological timekeeping mechanisms responsible for these seasonal changes. Several environmental cues have been identified that initiate or modify reproductive processes in invertebrates. Seasonal adaptations are often the result of changes in day length (photoperiod). As photoperiod is an accurate predictor of changing seasons, many species have evolved the ability to use changes in photoperiod to predict upcoming environmental change. One mediator of photoperiod information, 5-methoxyindole melatonin, has been identified in many vertebrate species as well as in a number of invertebrates (Wayne, 2001; Gorbet & Steel, 2003). The duration of the melatonin signal provides information about day length. The nightly elevation of melatonin varies with the length of night, the long nights (short days) of winter resulting in a relatively long duration of melatonin release. It is this duration that allows animals to decipher the seasons. In molluscs, melatonin has been identified in the ocular tentacles, visceral ganglion, brain, eyes and the cerebral ganglia (Wayne, 2001; Blanc et al., 2003). In most invertebrates studied to date, melatonin is elevated during the night, thus potentially playing a role in daily and annual rhythms. In addition, another 5-methoxyindole, 5-methoxytryptophol (5-ML), has also been shown to oscillate in a number of vertebrate species as well as gastropods (Blanc et al., 2003). At present, it is unclear what role 5-ML may play in daily circadian or seasonal rhythms. In addition to photoperiod, several other factors have been implicated in the seasonal regulation of reproductive differentiation and breeding. Water temperature is the predominant environmental cue triggering the onset of breeding in some species of molluscs, whereas the seasonal availability of food has been shown to influence sex differentiation and breeding in other species (review by Wayne, 2001). While various environmental cues have been investigated as triggers for either reproductive differentiation or breeding in molluscs, few studies have examined the potential for an underlying seasonal timer. In this paper, we investigate whether the seasonal onset of regression in mud snails is controlled by two environmental cues, photoperiod or temperature. Mud snails (Ilyanassa obsoleta ) were collected from a field population on Oak Island, North Carolina, USA, in January 2006. Imposex females have never been detected in this field population. Snails were rinsed with seawater to remove mud and sand, and transported to the laboratory in seawater from the sample location. Once in the laboratory, snails were held in 8-l glass aquaria containing 1 l of reconstituted seawater (35 + 1 ppt) (Instant Ocean; Aquarium Systems, Mentor, OH). Solutions were changed every other day. Seasonal control (SC) snails were held in photoperiods and water temperatures that changed commensurate with the field site according to the meteorological websites http://www.weather.com (Oak Island, NC) and http://storms.nos.noaa.gov (Wilmington, NC), respectively. Peak water temperature for this population generally occurs approximately 1.5 months after the summer solstice, while water temperatures are lowest approximately 1.5 months after the winter solstice (Sternberg et al., 2007). Phasedelayed (PD) snails were held for 4.5 months at a constant photoperiod and temperature consistent with that of early February at the field site. After 4.5 months, snails were released from these conditions and maintained in seasonally progressing conditions that mimicked the sample site conditions but with a 4.5 month delay. Starting in February 2006, a sub-sample of the snails from each treatment was collected monthly, except as noted, for evaluation of reproductive status. The November collection}, journal={JOURNAL OF MOLLUSCAN STUDIES}, author={Hotchkiss, Andrew K. and Sternberg, Robin M. and LeBlanc, Gerald A.}, year={2008}, month={Aug}, pages={301–303} }
 @article{hotchkiss_ankley_wilson_hartig_durhan_jensen_martinovi_gray_2008, title={Of Mice and Men (and Mosquitofish): Antiandrogens and Androgens in the Environment}, volume={58}, ISSN={["1525-3244"]}, DOI={10.1641/B581107}, abstractNote={Androgens are hormones produced by the gonads and other endocrine organs of vertebrates. Testosterone, along with its metabolite dihydrotestosterone, is critical for the differentiation of the fetal male reproductive tract from an indifferent state, for the development of male traits during puberty, and for the maintenance of reproductive function in mature animals. The androgen signaling pathway is highly conserved in the reproductive system of all vertebrates from fish to humans; therefore, environmental chemicals have the potential to induce adverse effects in any vertebrate species. There are synthetic androgens present in the environment, and several pesticides and toxic substances display antiandrogenic activity. For example, exposure to mixtures of antiandrogens during sexual differentiation results in cumulative adverse effects in male rat offspring. Continued characterization of the role of androgens in reproductive and other systems is warranted to enable better understanding of the potential adverse effects of chemical disruption of androgen signaling.}, number={11}, journal={BIOSCIENCE}, author={Hotchkiss, Andrew K. and Ankley, Gerald T. and Wilson, Vickie S. and Hartig, Phillip C. and Durhan, Elizabeth J. and Jensen, Kathleen M. and Martinovi, Dalivia and Gray, Leon E., Jr.}, year={2008}, month={Dec}, pages={1037–1050} }
 @article{sternberg_hotchkiss_leblanc_2008, title={Synchronized expression of retinoid X receptor mRNA with reproductive tract recrudescence in an imposex-susceptible mollusc}, volume={42}, ISSN={["1520-5851"]}, DOI={10.1021/es702381g}, abstractNote={The biocide tributyltin (TBT) causes the development of male sex characteristics in females of some molluscan species, a phenomenon known as imposex. Recent evidence suggests that the retinoid X receptor (RXR) participates in TBT-induced imposex. Accordingly, we hypothesized that RXR may contribute to the seasonal development of the male reproductive tract in molluscs and would be expressed in concert with this phenomenon. RXR was cloned and sequenced from an imposex-susceptble species, the eastern mud snail Ilyanassa obsoleta. The DNA-binding domain of the receptor protein was 100 and 97% identical to those of the rock shell Thais clavigera and the freshwater snail Biomphalaria glabrata. The ligand-binding domain was 93 and 92% identicalto the LBD of these two molluscan species, respectively. Phylogenetic analyses revealed that RXR is an ancient nuclear receptor whose origin predates the emergence of the Bilateria. Interestingly, though inexplicably, the molluscan RXRs were more similar to sequences of vertebrate RXRs than to the RXRs of other lophotrochozoan invertebrates. Next, the expression of RXR mRNA levels in the reproductive tract was determined through the reproductive cycle. RXR mRNA levels increased commensurate with reproductive tract recrudescence in both sexes. However, the timing of coordinate recrudescence-RXR expression differed between sexes. Results demonstrate that RXR expression is associated with reproductive tract recrudescence in both sexes; although, the timing of recrudescence may dictate sex-specific development. Retinoid signaling initiated by TBT during an inappropriate time in females may result in imposex.}, number={4}, journal={ENVIRONMENTAL SCIENCE & TECHNOLOGY}, author={Sternberg, Robin M. and Hotchkiss, Andrew K. and Leblanc, Gerald A.}, year={2008}, month={Feb}, pages={1345–1351} }
 @article{sternberg_hotchkiss_leblanc_2008, title={The contribution of steroidal androgens and estrogens to reproductive maturation of the eastern mud snail Ilyanassa obsoleta}, volume={156}, ISSN={["1095-6840"]}, DOI={10.1016/j.ygcen.2007.12.002}, abstractNote={Molluscs exposed to endocrine-disrupting chemicals (EDCs) have exhibited changes in reproductive tract development that are typically associated with androgen or estrogen signaling in vertebrates. However, a role for androgens and estrogens in molluscan reproductive endocrinology has yet to be established. In this study, we investigated putative roles for steroidal androgens and estrogens in recrudescence of the eastern mud snail Ilyanassa obsoleta. Our objectives were to: (1) identify associations among concentrations of testosterone and 17beta-estradiol, sex, and reproductive status in mud snails that suggest these hormones are involved in recrudescence; and (2) determine whether mud snails express NR3C4-like (androgen receptor) and NR3A-like (estrogen receptor) mRNAs in a manner indicative of a role in recrudescence. Temporal changes in testosterone levels in males were consistent with a positive role in recrudescence. Such a trend was not evident in females or for 17beta-estradiol in either sex. Efforts to identify an androgen receptor from the mud snail using targeted, degenerate RT-PCR were unsuccessful. However, an estrogen receptor (ER) cDNA was identified that is highly similar to known ERs of other molluscs. Studies with the ER of other molluscs have shown that this protein does not actually bind estrogens. We therefore considered the possibility that the mud snail ER may regulate reproductive maturation as a ligand-independent transcription factor based upon its tissue abundance. Males expressed greater levels of ER mRNA than did females over the entire reproductive cycle, and this difference was most evident during recrudescence. ER mRNA levels were significantly elevated during recrudescence in males but not females. In conclusion, testosterone may have a role in male reproductive tract recrudescence; however, this putative activity is independent of a NR3C4-type androgen receptor. The ER also may function in male recrudescence, though apparently independent of 17beta-estradiol. The retinoid signaling pathway is discussed as a possible alternative hormone/receptor-mediated signaling pathway that regulates male recrudescence.}, number={1}, journal={GENERAL AND COMPARATIVE ENDOCRINOLOGY}, author={Sternberg, Robin M. and Hotchkiss, Andrew K. and LeBlanc, Gerald A.}, year={2008}, month={Mar}, pages={15–26} }
 @article{hotchkiss_lambright_ostby_parks-saldutti_vandenbergh_gray_2007, title={Prenatal testosterone exposure permanently masculinizes anogenital distance, nipple development, and reproductive tract morphology in female Sprague-Dawley rats}, volume={96}, ISSN={["1096-6080"]}, DOI={10.1093/toxsci/kfm002}, abstractNote={In mammals, abnormal increases in fetal androgens disrupt normal development of the female phenotype. Due to the recent concern regarding environmental androgen-active chemicals, there is a need to identify sources of fetal androgen variation and sensitive developmental markers for androgenic activity in female rats. Anogenital distances (AGD), nipple retention, reproductive tract, and external genitalia are morphological parameters organized by prenatal androgens and are predictive of altered masculinized/defeminized phenotype in adult female mice and rats. The objectives of this study were to (1) characterize the natural prenatal androgen environment of rats including the magnitude of the intrauterine position (IUP) effect, (2) characterize the permanent effects of prenatal androgen exposure on female rats, and (3) determine the ability of AGD and areolas to predict these permanent androgenic alterations in female rats. Untreated male fetal rats had higher tissue testosterone (T) concentrations than females in the amniotic fluid, reproductive tract, gonad, and fetal body. The intrauterine position (IUP) of male and female fetuses did not affect T concentrations or AGD in male or female rats at gestational day (GD) 22. Female offspring exposed to 0, 1.5, and 2.5 mg/kg/day testosterone propionate (TP) on GDs 14-18 displayed increased AGD at postnatal day (PND) 2 and decreased nipples at PND 13 and as adults. TP-induced changes in neonatal AGD and infant areola number were reliable indicators of permanently altered adult phenotype in female rats. Further, females in the two high-dose groups displayed increased incidences of external genital malformations and the presence of prostatic tissue, not normally found in female rats.}, number={2}, journal={TOXICOLOGICAL SCIENCES}, author={Hotchkiss, Andrew K. and Lambright, Christy S. and Ostby, Joseph S. and Parks-Saldutti, Louise and Vandenbergh, John G. and Gray, Leon E., Jr.}, year={2007}, month={Apr}, pages={335–345} }
 @article{hotchkiss_vandenbergh_2005, title={The  anogenital distance index of mice (Mus musculus domesticus): An analysis}, volume={44}, number={4}, journal={Contemporary Topics in Laboratory Animal Science}, author={Hotchkiss, A. K. and Vandenbergh, J. G.}, year={2005}, pages={46–48} }
 @article{hotchkiss_parks-saldutti_ostby_lambright_furr_vandenbergh_gray_2004, title={A mixture of the "antiandrogens" linuron and butyl benzyl phthalate alters sexual differentiation of the male rat in a cumulative fashion}, volume={71}, ISSN={["1529-7268"]}, DOI={10.1095/biolreprod.104.031674}, abstractNote={Abstract Prenatal exposure to environmental chemicals that interfere with the androgen signaling pathway can cause permanent adverse effects on reproductive development in male rats. The objectives of this study were to 1) determine whether a documented antiandrogen butyl benzyl phthalate (BBP) and/or linuron (an androgen receptor antagonist) would decrease fetal testosterone (T) production, 2) describe reproductive developmental effects of linuron and BBP in the male, 3) examine the potential cumulative effects of linuron and BBP, and 4) investigate whether treatment-induced changes to neonatal anogenital distance (AGD) and juvenile areola number were predictive of adult reproductive alterations. Pregnant rats were treated with either corn oil, 75 mg/kg/day of linuron, 500 mg/kg/day of BBP, or a combination of 75 mg/kg/day linuron and 500 mg/kg/day BBP from gestational Day 14 to 18. A cohort of fetuses was removed to assess male testicular T and progesterone production, testicular T concentrations, and whole-body T concentrations. Male offspring from the remaining litters were assessed for AGD and number of areolae and then examined for alterations as young adults. Prenatal exposure to either linuron or BBP or BBP + linuron decreased T production and caused alterations to androgen-organized tissues in a dose-additive manner. Furthermore, treatment-related changes to neonatal AGD and infant areolae significantly correlated with adult AGD, nipple retention, reproductive malformations, and reproductive organ and tissue weights. In general, consideration of the dose-response curves for the antiandrogenic effects suggests that these responses were dose additive rather than synergistic responses. Taken together, these data provide additional evidence of cumulative effects of antiandrogen mixtures on male reproductive development.}, number={6}, journal={BIOLOGY OF REPRODUCTION}, author={Hotchkiss, AK and Parks-Saldutti, LG and Ostby, JS and Lambright, C and Furr, J and Vandenbergh, JG and Gray, LE}, year={2004}, month={Dec}, pages={1852–1861} }
 @article{wolf_hotchkiss_ostby_leblanc_gray_2002, title={Effects of prenatal testosterone propionate on the sexual development of male and female rats: A dose-response study}, volume={65}, ISSN={["1096-6080"]}, DOI={10.1093/toxsci/65.1.71}, abstractNote={Testosterone plays a major role in male sexual development. Exposure of females to testosterone in utero can induce masculine characteristics such as anovulation, increased anogenital distance (AGD), absence of nipples, retention of male-like tissues, and agenesis of the lower vagina. In addition, high levels of androgens during fetal development can lead to toxic effects such as reduced litter size and viability. The study of the effects of testosterone administration during sexual differentiation provides a foundation for understanding the effects of environmental androgens on fetuses, a sensitive subpopulation. In the current study, we investigated the ability of a range of concentrations of testosterone propionate (TP) administered prenatally to masculinize female and alter male offspring, and measured maternal and fetal T levels. Pregnant Sprague-Dawley rats were dosed by sc injection on gestational day (GD) 14-19 (GD 1= day of plug) with either corn oil (vehicle; 0.1 ml/rat) or with 0.1 ml of TP solution at 0.1, 0.5, 1, 2, 5, or 10 mg/0.1 ml. Parturition was delayed at 2, 5, and 10 mg TP, litter size was reduced at 5 and 10 mg TP, and pup weight was significantly reduced in both sexes at 0.5 mg TP and higher doses. Viability of offspring was unaffected at any dosage level. Androgenic effects seen at 0.5 mg TP in females included increased AGD at weaning and adulthood, reduced number of areolas and nipples, cleft phallus, small vaginal orifice, and presence of prostate tissue. This dose of TP elevated maternal T levels 10x but had no effect on fetal T levels. At 1 mg TP and above, female AGD on postnatal day (PND) 2 (or postcoital day 24 [gestation length = 22(1/2)]) was increased; areolas and nipples were virtually eliminated; levator ani muscle, bulbourethral glands, and seminal vesicles (2 mg TP and above) were present; none of the females developed a vaginal orifice and many females in the 1 and 2 mg TP dose groups developed a greatly distended, fluid-filled uterus after puberty. Maternal T levels at 1 mg TP were elevated 30x, and female fetal T levels showed an 80% increase. Male offspring displayed a reduced AGD and body weight on PND 2 at 0.5 mg TP and higher doses. These effects were not evident by weaning and male offspring displayed no malformations. We conclude that gestational administration of 0.5 and 1 mg TP masculinizes female offspring without greatly affecting pup viability or pregnancy of the dam. This study provides a useful model for in utero testing of environmental androgens for their potential to induce developmental abnormalities.}, number={1}, journal={TOXICOLOGICAL SCIENCES}, author={Wolf, CJ and Hotchkiss, A and Ostby, JS and LeBlanc, GA and Gray, LE}, year={2002}, month={Jan}, pages={71–86} }
 @misc{vandenbergh_konzelmann_hotchkiss_2001, title={Altering sex ratio of offspring in mammals}, volume={6,221,857}, number={2001 April 24}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Vandenbergh, J. G. and Konzelmann, J. A and Hotchkiss, A. K.}, year={2001} }
 @article{lambright_ostby_bobseine_wilson_hotchkiss_mann_gray_2000, title={Cellular and molecular mechanisms of action of linuron: An antiandrogenic herbicide that produces reproductive malformations in male rats}, volume={56}, ISSN={["1096-0929"]}, DOI={10.1093/toxsci/56.2.389}, abstractNote={Antiandrogenic chemicals alter sex differentiation by several different mechanisms. Some, like flutamide, procymidone, or vinclozolin compete with androgens for the androgen receptor (AR), inhibit AR-DNA binding, and alter androgen-dependent gene expression in vivo and in vitro. Finasteride and some phthalate esters demasculinize male rats by inhibiting fetal androgen synthesis. Linuron, which is a weak competitive inhibitor of AR binding (reported Ki of 100 microM), alters sexual differentiation in an antiandrogenic manner. However, the pattern of malformations more closely resembles that produced by the phthalate esters than by vinclozolin treatment. The present study was designed to determine if linuron acted as an AR antagonist in vitro and in vivo. In vitro, we (1) confirmed the affinity of linuron for the rat AR, and found (2) that linuron binds human AR (hAR), and (3) acts as an hAR antagonist. Linuron competed with an androgen for rat prostatic AR (EC(50) = 100-300 microM) and human AR (hAR) in a COS cell-binding assay (EC(50) = 20 microM). Linuron inhibited dihydrotestosterone (DHT)-hAR induced gene expression in CV-1 and MDA-MB-453-KB2 cells (EC(50) = 10 microM) at concentrations that were not cytotoxic. In short-term in vivo studies, linuron treatment reduced testosterone- and DHT-dependent tissue weights in the Hershberger assay (oral 100 mg/kg/d for 7 days, using castrate-immature-testosterone propionate-treated male rats; an assay used for decades to screen for AR agonists and antagonists) and altered the expression of androgen-regulated ventral prostate genes (oral 100 mg/kg/d for 4 days). Histological effects of in utero exposure to linuron (100 mg/kg/d, day 14-18) or DBP (500 mg/kg/d, day 14 to postnatal day 3) on the testes and epididymides also are shown here. Taken together, these results support the hypothesis that linuron is an AR antagonist both in vivo and in vitro, but it remains to be determined if linuron alters sexual differentiation by additional mechanisms of action.}, number={2}, journal={TOXICOLOGICAL SCIENCES}, author={Lambright, C and Ostby, J and Bobseine, K and Wilson, V and Hotchkiss, AK and Mann, PC and Gray, LE}, year={2000}, month={Aug}, pages={389–399} }
 @article{gray_price_lambright_wolf_hotchkiss_parks_ostby_1999, title={Environmental antiandrogens: The malformation pattern varies with the mechanism of antiandrogenic action.}, volume={60}, number={1999}, journal={Biology of Reproduction}, author={Gray, L. E. and Price, M. and Lambright, C. and Wolf, C. and Hotchkiss, A. and Parks, L. and Ostby, J.}, year={1999}, pages={201} }
 @article{howdeshell_hotchkiss_thayer_vandenbergh_saal_1999, title={Environmental toxins - Exposure to bisphenol A advances puberty}, volume={401}, ISSN={["1476-4687"]}, DOI={10.1038/44517}, number={6755}, journal={NATURE}, author={Howdeshell, KL and Hotchkiss, AK and Thayer, KA and Vandenbergh, JG and Saal, FS}, year={1999}, month={Oct}, pages={763–764} }