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Phthalates, widely used as plasticizers, have been increasingly linked to male reproductive toxicity through mechanisms including oxidative stress, endocrine disruption, inflammation, and apoptosis. This comprehensive review evaluates the protective role of various antioxidants in mitigating the detrimental effects of phthalates such as di-(2-ethylhexyl) phthalate (DEHP), di-butyl phthalate (DBP), mono-(2-ethylhexyl) phthalate (MEHP), and monobutyl phthalate (MBP) on male reproductive health. Antioxidants such as lycopene, ellagic acid, genistein, and selenium compounds exhibit significant efficacy in counteracting phthalate-induced damage by neutralizing reactive oxygen species (ROS), enhancing endogenous antioxidant defenses, reducing inflammatory responses, and preventing apoptosis. Lycopene demonstrates broad-spectrum protective effects, particularly through its high ROS-scavenging capacity and ability to preserve mitochondrial function. Ellagic acid effectively ameliorates oxidative stress and inflammation, while genistein enhances the Nrf2 pathway and restores hormonal balance, offering robust protection against reproductive toxicity. Selenium compounds improve antioxidant enzyme activities, providing essential support against oxidative damage. These findings underscore the potential of antioxidants as therapeutic agents against phthalate-induced male reproductive dysfunction. Future research should focus on optimizing antioxidant combinations, understanding dose-response relationships, and assessing long-term efficacy and safety to develop effective interventions for safeguarding male reproductive health., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Di(2-ethylhexyl) terephthalate (DEHTP) is an alternative plasticizer widely used in numerous consumer products, replacing di(2-ethylhexyl) phthalate (DEHP). Hence, DEHTP has been frequently detected in the environment and humans. As a structural isomer and functional analog of DEHP, DEHTP is a suspected endocrine disruptor. Here, we evaluated thyroid-disrupting effects of DEHTP using embryo-larval and adult male zebrafish. We also investigated its sex hormone disruption potential in the adult zebrafish. After 5- and 7-days of exposure to DEHTP, significant increases in whole-body thyroid hormonal levels were observed in the larval fish. Down-regulation of several thyroid-regulating genes, including trh, tshβ, nis, and dio2, was observed, but only after 5-day exposure. Following a 21-day exposure, the adult male zebrafish exhibited a significant decrease in total triiodothyronine and an increase in thyroid-stimulating hormones. Potential changes in the deiodination of thyroid hormones, supported by the up-regulation of two deiodinases, dio1 and dio3a, along with the down-regulation of dio2, could explain the thyroid hormone changes in the adult zebrafish. Moreover, significant trends of decrease in estradiol and 11-ketotestosterone, along with increase of testosterone (T), were observed in the adult zebrafish. Up-regulation of several steroidogenic genes may explain elevated T, while exact mechanisms of action warrant further investigation. Our results demonstrate that DEHTP can cause disruptions of thyroid and sex hormones at different life stages in zebrafish., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Objective: As an environmental endocrine disruptor, mono-2-ethylhexyl phthalate (MEHP) can interfere with liver metabolism and lead to liver diseases. We aimed to investigate the role of MEHP in liver fibrosis and its molecular mechanism., Methods: BRL-3A hepatocytes were exposed to MEHP (0, 10, 50, 100 and 200 μM) for 24 h. STAT5A gene was overexpressed by lentivirus transfection. The reactive oxygen species (ROS) was tested by the flow cytometer. The malondialdehyde (MDA), glutathione peroxidase (GSH-PX), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were detected by commercial kits. Real-Time PCR and Western blot were performed to test the relative mRNA and proteins levels, respectively., Results: MEHP exposure significantly induced oxidative damage in BRL-3A cells, which inhibited the expression of STAT5A and promoted the expression of fibrosis related proteins MMP2, MMP9, TIMP2 and CTGF. After over-expression of STAT5A gene in BRL-3A cells, the elevated expression levels of CTGF, MMP2, MMP9 and TIMP2 induced by MEHP exposure were significantly reversed., Conclusion: This study demonstrated that MEHP exposure inhibited the expression of STAT5A by causing oxidative damage in BRL-3A hepatocytes, thus accelerating the expression of key molecules in fibrosis and promoting the occurrence of liver fibrosis., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Liver steatosis has been associated with various etiological factors (obesity, alcohol, environmental contaminants). How those factors work together to induce steatosis progression is still scarcely evaluated. Here, we tested whether phthalates could potentiate death of steatotic hepatocytes when combined with ethanol. Pre-steatotic WIF-B9 hepatocytes were co-exposed to mono (2-ethylhexyl) (MEHP, 500 nM; main metabolite of di (2-ethylhexyl) phthalate or DEHP) and ethanol (5 mM) for 5 days. An increased apoptotic death was detected, involving a DNA damage response. Using 4-Methypyrazole to inhibit ethanol metabolism, and CH-223191 to antagonize the AhR receptor, we found that an AhR-dependent increase in alcohol dehydrogenase (ADH) activity was essential for cell death upon MEHP/ethanol co-exposure. Toxicity was also prevented by HET0016 to inhibit the cytochrome P450 4A (CYP4A). Using the antioxidant thiourea, a role for oxidative stress was uncovered, notably triggering DNA damage. Finally, co-exposing the in vivo steatosis model of high fat diet (HFD)-zebrafish larvae to DEHP (2.56 nM)/ethanol (43 mM), induced the pathological progression of liver steatosis alongside an increased Cyp4t8 (human CYP4A homolog) mRNA expression. Altogether, these results further emphasized the deleterious impact of co-exposures to ethanol/environmental pollutant towards steatosis pathological progression, and unraveled a key role for ADH and CYP4A in such effects., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Mono(2-ethylhexyl)phthalate (MEHP) promotes adipogenesis via PPARγ. PPARγ agonists, e.g., rosiglitazone (RSG), enhance adipocyte browning. However, scientific evidence regarding MEHP as a browning chemical is lacking. This study combined 3T3-L1 adipocytes and C57BL/6J mice to examine the potential roles of MEHP in browning. MEHP and the browning agent RSG caused similar energy metabolism in adipocytes. Both MEHP and RSG caused transcriptional changes involved in browning-associated thermogenesis, energy homeostasis, inflammatory response, and glucose uptake. MEHP-treated adipocytes exhibited brown adipocyte-like characteristics, i.e., increased mitochondrial proton leak, triiodothyronine-induced Bmp8b expression, decreased inflammation, and smaller lipid droplets. Increased PDK4 and PEPCK1 in MEHP/RSG-treated adipocytes could block glucose utilization for mitochondrial respiration. Mitochondrial/peroxisomal biogenesis and fatty acid β-oxidation in MEHP-treated adipocytes were enhanced. Candidate genes in promoting browning of MEHP-treated adipocytes were highlighted. In di(2-ethylhexyl)phthalate (DEHP)-treated mice, transcriptional changes in white adipose tissue (WAT) were associated with adipocyte differentiation, lipid synthesis, carbohydrate uptake, and WAT/brown adipose tissue (BAT) quantity. PPARγ and NR4A1 were predicted as the top two upstream regulators in orchestrating transcriptional changes. DEHP-treated mice exhibited actively expressed browning marker genes (i.e., Pparg, Adrb1, Adrb3, Ppargc1a, and Ucp1) in WAT, increased blood FGF21 levels, and higher amounts of BAT, supporting the browning-like effects in vivo., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Phthalate esters, suspected endocrine disrupting chemicals, are used in a wide range of applications. Because phthalate esters are not covalently bound, they can easily leach into the indoor environment and associate to dust particles. Thus, exposure may occur through inhalation, ingestion, or contact with the skin. However, it is unclear to what degree indoor dust contributes to the daily intake of phthalate esters. This study investigates household dust as an exposure pathway for seven phthalate esters, the monoester MEHP, and the plasticizer DINCH. Household dust collected from children's sleeping rooms and from living rooms were analysed using gas and liquid chromatography tandem mass spectrometry. To compare two exposure pathways, different dust particle sizes were generated: a respirable fraction (<5 μm) and an ingested particle fraction in the anticipated size range of skin adherence (<75 μm). Modelling of dust inhalation and ingestion showed that the daily intake of dust-bound phthalate esters was likely to be 2 times (inhalation) to 12 times (ingestion) higher for 21-month-old children than for adults. These children's daily uptake of phthalate esters was 40-140 times higher through ingestion than inhalation. Furthermore, dust may be an exposure pathway for phthalate esters as well as for MEHP. Therefore, phthalate monoesters could be environmental contaminants of their own and need to be considered in health risk assessments., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Mono(2-ethylhexyl) phthalate (MEHP) is the bioactive metabolite of di(2-ethylhexyl) phthalate, a plasticizing agent and persistent environmental contaminant associated with obesity, developmental abnormalities, and oxidative stress. Nrf2 (Nfe2l2) is a transcription factor that regulates cytoprotective genes as part of the adaptive antioxidant response. We previously identified the pancreas as a sensitive target of oxidative stress during embryonic development. The goals of this study were to 1) characterize the effects of MEHP exposure on pancreatic development, and 2) determine whether oxidative stress contributes to MEHP embryotoxicity. Zebrafish (Danio rerio) embryos from AB wildtype and Tg(ins:GFP;nrf2a fh318/fh318 ) were exposed to 0 or 200 μg/L MEHP at 3 h post fertilization (hpf) through 168 hpf to assess pancreatic organogenesis. MEHP exposure significantly decreased β-cell area at all timepoints (48, 72, 96, 168 hpf), but Nrf2a did not significantly protect against islet hypomorphism. Tg(gcga:GFP) embryos exposed to MEHP showed a decrease in α-cell area in the islet across the same timepoints. Tg(ptf1a:GFP) embryos were assessed at 80 and 168 hpf for exocrine pancreas length. MEHP exposure decreased growth of the exocrine pancreas. Expression of pancreas genes insa, sst2 and ptf1a was significantly reduced by MEHP exposure compared to controls. Glutathione (GSH) concentrations and redox potentials were quantified at 72 hpf by HPLC, but no significant changes were observed. However, expression of the GSH-related genes gstp1 and gsr were significantly altered by MEHP exposure. These data indicate that the developing pancreas is a sensitive target tissue of embryonic exposure to MEHP., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

A few different exposure prediction tools were evaluated for use in the new in vitro-based safety assessment paradigm using di-2-ethylhexyl phthalate (DEHP) and dibutyl phthalate (DnBP) as case compounds. Daily intake of each phthalate was estimated using both high-throughput (HT) prediction models such as the HT Stochastic Human Exposure and Dose Simulation model (SHEDS-HT) and the ExpoCast heuristic model and non-HT approaches based on chemical specific exposure estimations in the environment in conjunction with human exposure factors. Reverse dosimetry was performed using a published physiologically based pharmacokinetic (PBPK) model for phthalates and their metabolites to provide a comparison point. Daily intakes of DEHP and DnBP were estimated based on the urinary concentrations of their respective monoesters, mono-2-ethylhexyl phthalate (MEHP) and monobutyl phthalate (MnBP), reported in NHANES (2011-2012). The PBPK-reverse dosimetry estimated daily intakes at the 50th and 95th percentiles were 0.68 and 9.58 μg/kg/d and 0.089 and 0.68 μg/kg/d for DEHP and DnBP, respectively. For DEHP, the estimated median from PBPK-reverse dosimetry was about 3.6-fold higher than the ExpoCast estimate (0.68 and 0.18 μg/kg/d, respectively). For DnBP, the estimated median was similar to that predicted by ExpoCast (0.089 and 0.094 μg/kg/d, respectively). The SHEDS-HT prediction of DnBP intake from consumer product pathways alone was higher at 0.67 μg/kg/d. The PBPK-reverse dosimetry-estimated median intake of DEHP and DnBP was comparable to values previously reported for US populations. These comparisons provide insights into establishing criteria for selecting appropriate exposure prediction tools for use in an integrated modeling platform to link exposure to health effects., (Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Mono(2-ethylhexyl) phthalate (MEHP), the active metabolite of di(2-ethylhexyl) phthalate (DEHP), has been known to have adverse effects on the reproductive system, urologic systems, hepatic, developmental toxicities and carcinogenicity. However, the effect of MEHP on cardiovascular toxicity remains unclear. Therefore, we aimed to evaluate the cytotoxic effects of MEHP and the possible molecular mechanism. We found that treatment of EA.hy 926 cells with MEHP induced autophagy at earlier time (6 h) in this study. Lysosomal membrane permeabilization (LMP) occurred, after treatment with MEHP for 12 h, followed by the release of cathepsin B. Autophagy inhibitor 3-methyladenine (3MA) attenuated MEHP-induced LMP and the release of cathepsin B in EA.hy 926 cells. Additionally, MEHP induced collapse of mitochondrial transmembrane potential, which was evidenced by JC-1 staining. Addition of 3MA relieved MEHP-induced apoptosis as assessed by the expression of caspase 3 and TUNEL assay, indicating that MEHP-induced apoptosis was autophagy-dependent. Cathepsin B inhibitor, CA-074 Me, suppressed MEHP-induced the mitochondria release of cytochrome c and apoptosis as well. In summary, our results suggest that MEHP induced autophagy-dependent apoptosis in EA.hy 926 cells through the lysosomal-mitochondrial axis. This study provides new mechanistic insights into MEHP-induced cardiovascular toxicity., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Certain phthalates have adverse effects on male reproductive functions in animals, and potentially affect human testicular function and spermatogenesis, but little is known about the active mechanisms. We measured the urinary and seminal phthalate metabolites and explored their associations on insulin-like factor 3 (INSL3) and semen quality. Urine, blood, and semen samples were collected from the male partners of subfertile (n = 253) and fertile (n = 37) couples in a reproductive center in southern Taiwan. INSL3, reproductive hormones, semen-quality, and 11 phthalate metabolites in urine and semen were measured. There were significant correlations in the distribution pattern of metabolites, such as the relative contribution of low or high molecular weight phthalate metabolites. The significantly monotonic trends in semen volume, sperm concentration and motility were associated with increasing quartiles of INSL3 (all p-trend < 0.001). In adjusted regression models, increases in urinary phthalate metabolites levels were adversely associated with sperm concentration (monobenzyl phthalate [MBzP], mono-2-ethylhexyl phthalate [MEHP] and MEHP%), motility (MBzP and MEHP) and INSL3 (MBzP, MEHP and MEHP%) (all p < 0.01). Higher seminal phthalate metabolite levels were associated with decreases in sperm concentration (MEHP and mono-2-ethyl-5-hydroxyhexyl phthalate), motility (mono-ethyl phthalate [MEP] and di-(2-ethylhexyl) phthalate [DEHP] metabolites), normal morphology (MEP), and INSL3 (monomethyl phthalate and MEP) (all p < 0.05). Our data suggest that INSL3 secretion, reproductive hormone balance, and sperm production and quality might be simultaneously adversely affected for individuals excreting increasing levels of phthalates metabolites (especially di-ethyl phthalate, butylbenzyl phthalate, and DEHP) in urine and semen samples., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Di-(2-ethylhexyl) phthalate (DEHP) is the most commonly used plasticizer for flexible polyvinyl chloride (PVC), which is also known as one of the environmental endocrine disruptors with the reproductive, developmental and embryonic toxicity after entering human body. Mono-2-ethylhexyl phthalate (MEHP) is one of the most complicate metabolites from DEHP in vivo and responsible for many toxic effects of DEHP. In order to evaluate human exposure to DEHP, a direct competitive enzyme-linked immunosorbent (dcELISA) based on monoclonal antibody (mAb) was developed to detect MEHP. A hybridoma cell line 4B9 secreting mAb against MEHP was prepared, and the horseradish peroxidase (HRP) labeled antigen as a probe in the dcELISA was made. After optimization of ELISA reaction conditions, the standard curve with a linear range from 0.56 to 1000 ng mL(-1) and a detection limit of 0.39 ng mL(-1) was established. The cross-reactivities of anti-MEHP mAb to other ten phthalate esters were less than 5% except for mono-methylphthalate (MME). The average recoveries of MEHP from distilled water and negative human urine were both between 87.4% and 94.72% with coefficient of variation (CV) less than 5%. Here, the ELISA method on detecting MEHP was successfully established and applied to real urine sample analyses and the results were confirmed by HPLC. Furthermore, it was indicated that the immunoassay was reliable and suitable for monitoring MEHP., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Phthalate diesters such as di (2-ethylhexyl) phthalate (DEHP) are considered ubiquitous contaminants and are poorly biodegraded in the environment. Moreover, both the parent compound and stable metabolites such as mono (2-ethylhexyl) phthalate (MEHP) are linked to several negative impacts on the environment and human health. Earlier work established that saturated diester compounds, such as succinates, showed better biodegradation characteristics and comparable plasticizer properties compared to DEHP. In this work we examine the effect of alkyl chain length of succinate molecules on plasticizer and biodegradation properties. This included both the side chains (n-ethyl to n-octyl) as well as substituents on the middle part of the succinate molecule. We showed that the common soil bacterium Rhodococcus rhodocrous could rapidly break down all unsubstituted succinates, without the appearance of stable metabolites. Furthermore, the organisms used the plasticizer metabolites as carbon source. The introduction of a large cyclohexyl substituent on the succinate resulted in a poorer degradation rate. Glass Transition Temperature (Tg) measurements were performed to evaluate plasticizer properties and showed that longer side chains reduced the Tg more efficiently, while large cyclohexyl substituents on the succinate decreased this effect. However, all compounds performed better or equal to DEHP at reducing the Tg., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

In the present study, the effects of MEHP on human hepatocellular liver carcinoma HepG2 cells were investigated. The results showed that MEHP-induced oxidative DNA damage in the treatment groups (≥ 25.00 μM) at 24h after treatment and in the 100.00 μM treatment group at 36 h after treatment (p < 0.05 or p < 0.01). At 36 h after treatment, MEHP at higher concentrations (≥ 25.00 μM) resulted in a decrease in ATP level, and an increase in the protein levels of cytochrome c and Smac/DIABLO in the cytosol as well as the percentage of apoptotic cells. The activation of caspase-9 and -3 and the expression of the selected apoptosis-related proteins, p53, PUMA, NOXA, Bax and Bcl-2 were also induced. Furthermore, vitamin C, a scavenger of reactive oxygen species, attenuated MEHP-induced apoptosis. These findings indicated that MEHP induced oxidative DNA damage and apoptosis in HepG2 cells, and p53 and its downstream proteins were involved in mitochondria- and caspase-mediated apoptosis induced by MEHP., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

In vitro fertilization (IVF) is one of the most important treatments of infertility to provide a chance of conceiving. In IVF treatment, sperm are washed and motile sperm are isolated with sperm washing media (SWM) for the purpose of fertilization; fertilized ova are then incubated for a maximum of 5 or 6d in media for IVF (IVFM). The exposure of fertilized ova to chemicals via such media has not been studied. We determined the concentrations of two contaminants; di(2-ethylhexyl)phthalate (DEHP) and its hydrolyzed product mono(2-ethylhexyl)phthalate (MEHP) in IVFM, SWM, and protein sources (PS: human serum albumin or serum substitute) for IVFM and SWM. The DEHP and MEHP in these media were extracted by a liquid-liquid extraction method and their concentrations determined by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Fifteen IVFM, nine SWM, and six PS obtained in Japan were examined. The concentrations of DEHP and MEHP in IVFM and SWM were <10-114 and <2.0-263 ng mL(-1), respectively. The concentrations of both DEHP and MEHP were higher in the media containing PS than in those without PS. Either MEHP alone or both DEHP and MEHP were detected in PS. The concentrations of DEHP and MEHP in PS were <10-982 and 47.0-1840 ng mL(-1), respectively. The DEHP and MEHP detected in these media were derived from PS. This is the first study on the chemical contamination of IVFM, SWM, and PS., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

This study was designed to investigate the hypothesis that the toxic effects of di(2-ethylhexyl)phthalate (DEHP), the most abundantly used plasticizer and ubiquitous environmental contaminant that cause alterations in endocrine and spermatogenic functions in animals is mediated through the induction of reactive oxygen species (ROS) and activation of nuclear p53 and p21 proteins in LNCaP human prostate adenocarcinoma cell line. Protective effects of two selenocompounds, sodium selenite (SS) and selenomethionine (SM) were also examined. It was demonstrated that 24 h exposure of the cells to 3 mM DEHP or its main metabolite, mono(2-ethylhexyl)phthalate (MEHP, 3 μM) caused strongly amplified production of ROS. Both SS (30 nM) and SM (10 μM) supplementations reduced ROS production, and p53 and p21 activation that induced significantly only by MEHP-exposure. The overall results of this study indicated that the induction of oxidative stress is one of the important mechanisms underlying the toxicity of DEHP and this is mainly through the effects of the metabolite, MEHP. Generated data also emphasized the critical role of Se in modulation of intracellular redox status, implicating the importance of the appropriate Se status in cellular response against testicular toxicity of phthalates., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

DEHP is known to cause reproductive toxicity in rats, particularly during the neonatal period. Pregnant and brood rats were treated by gavage with 750 mg/kgb.w./day DEHP starting on GD14 within PND4. Two hours after (14)C-DEHP administration on GD15, GD18, GD21 and PND4, the radioactivity content was measured in the dams blood and in the liver, gonads and carcass of the offspring. The radioactivity concentration recovered in the fetuses was one or two order of magnitude lower than the concentration found in the dam plasma. A low proportion of radioactivity was present in fetal gonads, ca. 2%, 5% and 3.6% on GD18, GD21 and PND4, respectively. The effect on testosterone production of DEHP and its metabolites (MEHP, metabolites VI and IX) was assessed in fetal testis cultures using a dose-range which included the maximal exposure observed in vivo. None of the compounds affected testosterone production. Thus, DEHP and/or its metabolites appear to cross the placental barrier, reach the fetal gonads. In vitro, neither DEHP nor its main metabolites decreased the testosterone production.

Testicular damage is a comparatively common finding in toxicity studies. Part of the susceptibility of the testis to chemical toxicity stems from the complexity of its normal structure, function and regulatory control. This complexity has stimulated the development and extensive use of testicular cell cultures in the study of normal testicular function. However, the potential of such systems for investigating chemically induced testicular toxicity has only recently been considered. Using primary co-cultures of Sertoli and germ cells many features of the well characterized testicular damage produced by phthalate esters and glycol ethers could be reproduced in vitro. These encouraging findings are discussed in relation to some of the likely limitations to the application of in vitro models for testicular toxicity.

Mixed cultures of Sertoli and germ cells were prepared from rat testes and their response to some model testicular toxins was studied. Cultures consisted of a monolayer of Sertoli cells to which clusters of spermatocytes and spermatogonia adhered. With time in culture, germ cells progressively detached from the Sertoli cells into the medium. Addition of mono-(2-ethylhexyl) phthalate (MEHP) to the culture medium resulted in a concentration-dependent increase in the rate of germ-cell detachment over the range 10(-7) - 10(-4) M. No such effect was produced by di-(2-ethylhexyl) phthalate or 2-ethylhexanol. An increased rate of germ-cell detachment was also produced by other phthalate monoesters known to cause testicular damage in vivo, whereas similar concentrations of a number of monophthalates not known to affect the testis in vivo had no such effect on the cultures. Known age and species differences in the testicular toxicity of di-(2-ethylhexyl) phthalate could be reproduced in cultures treated with MEHP. There was little effect on the viability of either germ cells or Sertoli cells at concentrations of MEHP that caused marked germ-cell detachment, but there were changes in Sertoli-cell morphology. Increased germ-cell detachment was also observed in cultures treated with 10(-7) - 10(-4) M-AF1312/TS, a compound that affects Sertoli cells in vivo, but was not seen in cultures exposed to a range of other testicular toxins with different target cells in the testis. Thus, the effects produced by phthalate monoesters in vitro may reflect damage to the Sertoli cells. Testicular cell cultures could be of value both for screening compounds and for studying underlying mechanisms of testicular toxicity.