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Classic toxicology studies often utilize in vivo animal models. Newer approaches employing in vitro organ-specific cellular models have been developed in recent years to help accelerate the speed and reduce the cost of traditional toxicology testing. Toward the goal of supporting in vitro cellular model research with a regulatory application in mind, we have developed a 'designer' human kidney cell line called HK2-Vi that can fluorescently measure the cytotoxicity of potential toxins on proximal tubule cell viability in a direct exposure in vitro model. HK2-Vi was designed to be a reagent-less kinetic assay that can yield data on short- or long-term cell viability after toxin exposure. To generate HK2-Vi, we used monocistronic lentiviral transduction methods to genetically engineer a human kidney cell line called HK-2 to stably co-express two transgenes. The first is Perceval HR, which encodes a fluorescent biosensor of both cytosolic ATP and ADP and the second is pHRed, which encodes a biosensor of cytosolic pH. Relative levels of cellular ATP and ADP effectively serve as a reliable and robust indicator of cell viability. Because the fluorescence Perceval HR is pH-dependent, we co-expressed the pHRed genetic biosensor to correct for variations in pH if necessary. Heterogenous populations of transduced renal cells were enriched by flow cytometry before monoclonal cellular populations were isolated by cell culture methods. A single clonal population of co-transduced cells expressing both Perceval HR and pHRed was selected to be HK2-Vi. This established cell line can now serve as a tool for in vitro toxicology testing and the methods described herein serve as a model for developing designer cell lines derived from other organs.
Asunto(s)
Línea Celular , Túbulos Renales Proximales/efectos de los fármacos , Pruebas de Toxicidad , Adenosina Difosfato/metabolismo , Adenosina Trifosfato/metabolismo , Técnicas Biosensibles , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Fluorescencia , Ingeniería Genética , Humanos , Concentración de Iones de Hidrógeno , Túbulos Renales Proximales/citología , Túbulos Renales Proximales/metabolismo , TransgenesRESUMEN
Background: Of the 1.8 million global incident lung cancer cases estimated in 2012, approximately 60% occurred in less developed regions. Prior studies suggest sex differences in lung cancer risk and a potential role for reproductive and hormonal factors in lung cancer among women. However, the majority of these studies were conducted in developed regions. No prior study has assessed these relationships among Nepali women. Methods: Using data from a hospital-based case-control study conducted in B. P. Koirala Memorial Cancer Hospital (Nepal, 2009-2012), relationships between reproductive and hormonal factors and lung cancer were examined among women aged 23-85 years. Lung cancer cases (n = 268) were frequency-matched to controls (n = 226) based on age (±5 years), ethnicity and residential area. The main exposures in this analysis included menopausal status, age at menarche, age at menopause, menstrual duration, gravidity, and age at first live-birth. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using multivariable logistic regression. Results: Among postmenopausal women, those with a younger age at menopause (<45 years; 45-49 years) had an increased odds of lung cancer compared to those with an older (≥50 years) age at menopause [OR (95%CI): 2.14 (1.09, 4.17); OR (95% CI): 1.93 (1.07, 3.51)], after adjusting for age and cumulative active smoking years. No statistically significant associations were observed with the other reproductive and hormonal factors examined. Conclusion: These results suggest that Nepali women with prolonged exposure to endogenous ovarian hormones, via later age at menopause, may have a lower odds of lung cancer.
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Carboxymethyl starches are added to food products for thickening or tablet binding/filling purposes. Although they lack toxicity, their synthesis creates the chemical byproduct diglycolic acid (DGA), which is difficult to eliminate and whose toxicity is in question. A rare case of an accidental direct exposure to extremely high concentrations of DGA in a person revealed that DGA has the potential to be toxic to several organs, with the kidneys and liver being the most affected organs. Given that DGA is present in our food supply as a chemical byproduct of carboxymethyl starch food additives, we sought to perform in vitro testing of its potential hepatotoxicity to help complement a recent in vivo rat acute dose-response study that also tested for the potential hepatotoxic effects of daily DGA ingestion by oral gavage over a period of 28â¯days. Using the HepG2/C3A cellular in vitro model, we tested how escalating doses of DGA exposure over 24â¯h could induce hepatotoxicity. Both in vitro and in vivo testing systems revealed that DGA is indeed a hepatotoxin once a certain exposure threshold is reached. The concordance of these models highlights the utility of in vitro testing to support and help predict in vivo findings.
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Aditivos Alimentarios , Glicolatos/toxicidad , Animales , Proteínas de Ciclo Celular/metabolismo , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Hemo-Oxigenasa 1/metabolismo , Células Hep G2 , Humanos , Hígado/citología , Hígado/efectos de los fármacos , Hígado/metabolismo , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Proteínas Asociadas a Resistencia a Múltiples Medicamentos/metabolismo , Proteínas Nucleares/metabolismo , Ratas Sprague-Dawley , Especies Reactivas de Oxígeno/metabolismo , Reproducibilidad de los ResultadosRESUMEN
Diglycolic acid (DGA) is present in trace amounts in our food supply and is classified as an indirect food additive linked with the primary GRAS food additive carboxymethyl cellulose (CMC). Carboxymethyl starches are used as a filler/binder excipient in dietary supplement tablets and a thickening ingredient in many other processed foods. We sought to utilize the human proximal tubule HK-2 cell line as an in vitro cellular model system to evaluate its acute nephrotoxicity of DGA. We found that DGA was indeed toxic to HK-2 cells in all in vitro assays in our study, including a highly sensitive Luminex assay that measures levels of an in vitro biomarker of kidney-specific toxicity, Kidney Injury Molecule 1 (KIM-1). Interestingly, in vitro KIM-1 levels also correlated with in vivo KIM-1 levels in urine collected from rats treated with DGA by daily oral gavage. The use of in vitro and in vivo models towards understanding the effectiveness of an established in vitro system to predict in vivo outcomes would be particularly useful in rapidly screening compounds that are suspected to be unsafe to consumers. The merit of the HK-2 cell model in predicting human toxicity and accelerating the process of food toxicant screening would be especially important for regulatory purposes. Overall, our study not only revealed the value of HK-2 in vitro cell model for nephrotoxicity evaluation, but also uncovered some of the mechanistic aspects of the human proximal tubule injury that DGA may cause.
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Adhatoda zeylanica is a dietary supplement ingredient present in several types of dietary supplements, including weight loss, respiratory relief, and immune regulating products. Due to its reported wide range of uses in folk medicine, it was hypothesized that it may have the potential to target multiple organs and lead to a range of toxicity features. As a preliminary evaluation of the safety of this herbal ingredient, an investigation into its effects on the kidney was sought. An in vitro study of its potential nephrotoxicity using the HK-2 human proximal tubule cell line in a variety of functional indicators was performed to capture both general forms of cellular toxicity as well as ones that are specific to proximal tubules. A. zeylanica was only capable of inducing detrimental short-term toxicity to HK-2 cells at relatively high treatment concentrations when exposed directly to the cells. The lack of acute and potent toxicity of A. zeylanica under our experimental conditions calls for further studies to better define its toxicant threshold and establish safe dosage levels.
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A human hepatoma cell line (HuH-7) was evaluated as a metabolically competent cell model to investigate cytochrome P450 3A4 (CYP3A4) inhibition, induction, and hepatotoxicity. First, CYP3A4 gene expression and activity were determined in HuH-7 cells under three culture conditions: 1-week culture, 3-week culture, or 1 % dimethyl sulfoxide (DMSO) treatment. HuH-7 cells treated with DMSO for 2 weeks after confluence expressed the highest CYP3A4 gene expression and activity compared to the other two culture conditions. Furthermore, CYP3A4 activity in DMSO-treated HuH-7 cells was compared to that in a human hepatoma cell line (HepG2/C3A) and human bipotent progenitor cell line (HepaRG), which yielded the following ranking: HepaRG > DMSO-treated HuH-7 >> HepG2/C3A cells. The effects of three known CYP3A4 inhibitors were evaluated using DMSO-treated HuH-7 cells. CYP3A4 enzyme inhibition in HuH-7 cells was further compared to human recombinant CYP3A4, indicating similar potency for reversible inhibitors (IC 50 within 2.5-fold), but different potency for the irreversible inhibitor. Next, induction of CYP3A4 activity was compared between DMSO-treated HuH-7 and HepaRG cells using two known inducers. DMSO-treated HuH-7 cells yielded minimal CYP3A4 induction compared to that in the HepaRG cells after 48-h treatments. Finally, the cytotoxicity of five known hepatotoxicants was evaluated in DMSO-treated HuH-7, HepG2/C3A, and HepaRG cells, and significant differences in cytotoxic sensitivity were observed. Overall, DMSO-treated HuH-7 cells are a valuable model for medium- or high-throughput screening of chemicals for CYP3A4 inhibition and hepatotoxicity.
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Citocromo P-450 CYP3A/metabolismo , Inhibidores Enzimáticos del Citocromo P-450/farmacología , Dimetilsulfóxido/farmacología , Hepatocitos/efectos de los fármacos , Hepatocitos/enzimología , Pruebas de Toxicidad/métodos , Carcinoma Hepatocelular/enzimología , Línea Celular Tumoral , Citocromo P-450 CYP3A/biosíntesis , Citocromo P-450 CYP3A/genética , Expresión Génica/efectos de los fármacos , Células Hep G2 , Humanos , Neoplasias Hepáticas/enzimologíaRESUMEN
Rauwolfia serpentina (or Snake root plant) is a botanical dietary supplement marketed in the USA for maintaining blood pressure. Very few studies have addressed the safety of this herb, despite its wide availability to consumers. Its reported pleiotropic effects underscore the necessity for evaluating its safety. We used a human kidney cell line to investigate the possible negative effects of R. serpentina on the renal system in vitro, with a specific focus on the renal proximal tubules. We evaluated cellular and mitochondrial toxicity, along with a variety of other kidney-specific toxicology biomarkers. We found that R. serpentina was capable of producing highly detrimental effects in our in vitro renal cell system. These results suggest more studies are needed to investigate the safety of this dietary supplement in both kidney and other target organ systems.
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Células Epiteliales/efectos de los fármacos , Mitocondrias/efectos de los fármacos , Extractos Vegetales/farmacología , Rauwolfia/química , Especies Reactivas de Oxígeno/agonistas , Línea Celular , Supervivencia Celular/efectos de los fármacos , Cisplatino/farmacología , Cistatina C/genética , Cistatina C/metabolismo , Relación Dosis-Respuesta a Droga , Células Epiteliales/citología , Células Epiteliales/metabolismo , Regulación de la Expresión Génica , Receptor Celular 1 del Virus de la Hepatitis A , Humanos , Túbulos Renales Proximales/citología , Túbulos Renales Proximales/efectos de los fármacos , Túbulos Renales Proximales/metabolismo , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Extractos Vegetales/química , Especies Reactivas de Oxígeno/metabolismo , Receptores Virales/genética , Receptores Virales/metabolismo , Ácido Valproico/farmacología , Microglobulina beta-2/genética , Microglobulina beta-2/metabolismoRESUMEN
Interactions among monoamine oxidase (MAO) inhibitors in drugs, botanicals, and dietary supplements may lead to unpredictable neurochemical dysfunction due to excessive inhibition or therapeutic invalidation. Often recombinant MAO or brain tissue homogenates have been used to evaluate MAO inhibitors such as the ß-carboline alkaloids (harmane, harmine, harmaline, and harmalol). However, there is a lack of cellular systems for evaluation of MAO activity, which represents a more advanced in vitro model compared to recombinant enzymes or tissue lysates. Using kynuramine assays, intracellular MAO inhibition by ß-carbolines was measured in PC12 (rat pheochromocytoma), MH1C1 (rat liver), and HuH-7 (human liver) cell lines, which were compared with human recombinant MAO and cell lysates. ß-Carbolines (1 µM, 90 min incubations) inhibited MAO by 40-99% in live PC12 cells where MAO A was the active isoform, and <12% in HuH-7 and MH1C1 cells where MAO B was primarily active. The combination index (CI), which serves as a quantitative indicator of pharmacological interactions, was determined for harmaline/harmine (CI, 1.01-1.25) and methylene blue/harmine (CI, 0.74-1.07) in PC12 cells. Overall, this study illustrates applications of cell-based in vitro assay platforms to gain a comprehensive understanding of intracellular MAO inhibitors and their interactions.
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Carbolinas/farmacología , Modelos Biológicos , Inhibidores de la Monoaminooxidasa/farmacología , Monoaminooxidasa/efectos de los fármacos , Alcaloides/farmacología , Animales , Línea Celular , Línea Celular Tumoral , Humanos , Hígado/citología , Hígado/efectos de los fármacos , Hígado/enzimología , Monoaminooxidasa/metabolismo , Células PC12 , Ratas , Especificidad de la EspecieRESUMEN
Non-steroidal anti-inflammatory drugs (NSAID) are a family of chemicals that function to reduce pain, fever, and inflammation, and they are commonly used in people and animals for this purpose. Currently there are no NSAIDs approved for the management of inflammation in swine due to a lack of validated animal models and suitable biomarkers to assess efficacy. A previous in vitro study examining biomarkers of inflammation identified fourteen genes that were significantly altered in response to Escherichia coli lipopolysaccharide (LPS)-induced inflammation. In the present study, five of those fourteen genes were tested in vivo to determine if the same effects observed in vitro were also observed in vivo. Plasma levels of prostaglandin E(2) (PGE(2)), an essential mediator of fever and inflammation, were also determined. Two groups of swine were stimulated with LPS with the second group also treated with flunixin meglumine. Blood was collected at 0, 1, 3, 6, 8, 24, and 48 h post LPS-stimulation. The RNA was extracted from the blood and quantitative real-time-PCR (qRT-PCR) was utilized to determine the expression patterns of CD1, CD4, serum amyloid A2 (SAA2), Caspase 1, and monocyte chemoattractant protein 1 (MCP-1). The LPS-stimulated animals demonstrated a statistically significant alteration in expression of SAA2 and CD1 at 3h post-stimulation. Flunixin meglumine treated animals' demonstrated reduced expression of CD1 in comparison to the LPS-stimulated swine at 24 and 48 h post LPS-stimulation. Flunixin meglumine treated animals exhibited reduced expression of SAA2 at 48 h post-stimulation compared to LPS-stimulated swine. Swine treated with LPS demonstrated statistically significant increases in plasma PGE(2) at 1h post-stimulation. Swine treated with flunixin meglumine had no increase in plasma PGE(2) levels at any time. These results demonstrate that PGE(2) production, along with two out of five genes (SAA2 and CD1) have the potential to serve as early biomarkers of inflammation as well as indicators of NSAID efficacy.
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Antiinflamatorios no Esteroideos/farmacología , Clonixina/análogos & derivados , Inflamación/veterinaria , Enfermedades de los Porcinos/sangre , Animales , Antígenos CD1/sangre , Biomarcadores/sangre , Antígenos CD4/sangre , Caspasa 1/sangre , Quimiocina CCL2/sangre , Clonixina/farmacología , Dinoprostona/sangre , Ensayo de Inmunoadsorción Enzimática/veterinaria , Inflamación/sangre , Inflamación/tratamiento farmacológico , Lipopolisacáridos/farmacología , Masculino , Reacción en Cadena en Tiempo Real de la Polimerasa/veterinaria , Proteína Amiloide A Sérica/análisis , Porcinos , Enfermedades de los Porcinos/tratamiento farmacológico , Enfermedades de los Porcinos/inmunología , Tromboxano B2/sangreRESUMEN
Traditional toxicological methods that utilize only single pure compounds may not accurately predict risks from substances with multiple chemical constituents. A complementary approach to conventional methodologies includes in vitro systems that assess toxicity of chemical mixtures and identify components that may adversely impact biological processes. Compared to animal models, in vitro assays are inexpensive, rapid, and reduce and refine related animal testing. We utilized HepG2/C3A cells as a hepatotoxicity screening model to evaluate the cytotoxic and metabolic effects of three commercially available oil dispersants, Corexit EC9500A and EC9527A and ZI-400. The surfactant DOSS, a primary active constituent of the Corexit dispersants, was also evaluated. Biologically relevant endpoints were measured including cell viability, oxidative stress, and mitochondrial activity. Significant increases in cytotoxicity were observed with Corexit dispersants (LC(50)â¼250 ppm), whereas ZI-400 was moderately cytotoxic (LC(50) >>400 ppm). Each dispersant caused an accumulation of reactive oxygen species and altered mitochondrial activity and other cellular processes. Generally, DOSS made notable contributions to the effects of EC9500A and EC9527A, however, they were observed at concentrations higher than those used in most consumer products. Overall, this system may represent a valuable complementary tool for predicting the toxicity of complex mixtures.
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Mezclas Complejas , Pruebas de Toxicidad , Línea Celular , Citocromo P-450 CYP1A1/metabolismo , Humanos , Técnicas In Vitro , Potenciales de la Membrana , Mitocondrias , Estrés OxidativoRESUMEN
Food intake, physical activity (PA), and genetic makeup each affect health and each factor influences the impact of the other 2 factors. Nutrigenomics describes interactions between genes and environment. Knowledge about the interplay between environment and genetics would be improved if experimental designs included measures of nutrient intake and PA. Lack of familiarity about how to analyze environmental variables and ease of access to tools and measurement instruments are 2 deterrents to these combined studies. This article describes the state of the art for measuring food intake and PA to encourage researchers to make their tools better known and more available to workers in other fields. Information presented was discussed during a workshop on this topic sponsored by the USDA, NIH, and FDA in the spring of 2009.
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Ejercicio Físico , Internet , Estado Nutricional , Programas Informáticos , Humanos , Medicina de PrecisiónRESUMEN
The present study was undertaken to assess, in vitro, the hepatotoxic potential of the food-borne mycotoxin, deoxynivalenol (DON), using rat (Clone9 and MH1C1), mouse (NBL CL2) and human (WRL68 and HepG2) liver cells in culture. The cells were treated with DON for 24 h at 37 degrees C in 5% CO(2) at concentrations of 0-25 microg ml(-1). Following the treatment period, the cells were assayed for biochemical markers of hepatotoxicity that included three independent cytotoxicity assays, oxidative stress and mitochondrial dysfunction. Concentration-dependent cytotoxicity of DON was observed in each of the five different liver cells derived from three different species (rat, mouse and human) over the entire concentration range studied, beginning at 0.1 microg ml(-1). At these concentrations DON did not induce a biologically significant increase in oxidative stress in these liver cells, and showed a significant decrease in the mitochondrial function only in the rat liver MH1C1 cells compared with the control. The results of this in vitro study suggest that DON is a potential hepatotoxin for the rat, mouse and human liver cells in the concentration range tested in this study. The liver cells used in this study showed distinct endpoint-sensitivity to DON related to the species.
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Hígado/efectos de los fármacos , Tricotecenos/toxicidad , Animales , Técnicas de Cultivo de Célula , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Enfermedad Hepática Inducida por Sustancias y Drogas/etiología , Enfermedades Transmitidas por los Alimentos/etiología , Humanos , Hígado/citología , Hígado/patología , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Ratones , Estrés Oxidativo/efectos de los fármacos , Ratas , Especificidad de la EspecieRESUMEN
Androstenedione, a naturally occurring steroid hormone, has been used to enhance athletic performance. Little is known, however, about its hepatotoxicity. Clone-9 cells, a non-transformed epithelial cell line that was originally isolated from normal liver of a 4-week old Sprague-Dawley rat, were used as an in vitro model to assess the hepatotoxic potential of androstenedione. The cultures were treated with androstenedione for 24 h at 37 degrees C in 5% CO(2) at concentrations of 0-100 microg ml(-1). After the treatment period, the cells and the culture supernatants were assayed for markers of cytotoxicity which included: release of liver enzymes, cell viability, cellular double-stranded DNA content, oxidative stress, steatosis, cellular ATP content, caspase-3 activity, the mitochondrial permeability transition and induction of cytochrome P450 activity. Significant concentration-dependent differences from control were observed in some endpoints at medium concentrations of 10 microg ml(-1) and above. These in vitro findings were compared with comparable endpoints obtained from an in vivo study of androstenedione toxicity in female Sprague-Dawley rats. Of the eight endpoints that could be compared between the two studies, only three (lipid accumulation, ATP depletion and P450 activity) appeared to be concordant. This suggests that, under the experimental conditions used, the clone-9 cells were not a good model for androstenedione hepatotoxicity.
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Androstenodiona/toxicidad , Enfermedad Hepática Inducida por Sustancias y Drogas/patología , Adenosina Trifosfato/metabolismo , Animales , Biomarcadores , Caspasa 3/metabolismo , Línea Celular , Células Clonales , ADN/biosíntesis , ADN/genética , Enzimas/sangre , Enzimas/metabolismo , Femenino , Hepatocitos/efectos de los fármacos , Hepatocitos/enzimología , Hígado/citología , Hígado/efectos de los fármacos , Hígado/patología , Modelos Biológicos , Estrés Oxidativo/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Reproducibilidad de los ResultadosRESUMEN
The oral toxicity of a single administration by gavage (10, 20 or 30 mg kg(-1) body weight) of colchicine (COL) was determined in young, mature male and female Sprague-Dawley rats. The effect of COL was evaluated in the presence or absence of additional treatment variables that included vehicle and lipopolysaccharide (LPS) pre-exposure. The vehicle for COL was either Half and Half cream (H & H) or saline, and each group included pretreatment with either saline or a low, minimally toxic dose (83 microg kg(-1) body weight) of LPS. Colchicine toxicity in both male and female age-matched rats was characterized by progressively more severe dose-related clinical signs of toxicity. These included mortality, decreased body weight and feed intake during the first several days after dosing, with recovery thereafter in surviving animals. There were differences in the severity of the toxic response to COL between male and female rats. The most notable sex-related difference was in COL lethality. Female rats were two times more susceptible to the lethal effects of COL than male rats. Saline or H & H delivery vehicles did not result in any apparent qualitative or quantitative differences in COL toxicity. LPS pretreatment significantly potentiated COL lethality in both males and females, although the potentiation in males was greater than in females. LPS pretreatment modestly increased the COL induced anorexic effect in surviving males, but not in surviving female animals. LPS did not appear to modulate either the body weights or clinical signs of COL induced toxicity in surviving males or females.
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Colchicina/toxicidad , Lipopolisacáridos/toxicidad , Administración Oral , Animales , Peso Corporal/efectos de los fármacos , Colchicina/administración & dosificación , Femenino , Dosificación Letal Mediana , Masculino , Vehículos Farmacéuticos , Ratas , Ratas Sprague-Dawley , Factores SexualesRESUMEN
Androstenedione, a naturally occurring steroid hormone, is a dietary supplement used to enhance athletic performance. Little is known, however, about the safety of its use by young adults including women of child bearing age. To test the possible hepatotoxic effects of androstenedione use, this study was undertaken using a rat model. Pregnant rats (six rats/dose) were exposed to androstenedione in corn oil by gastric intubation at 0, 5, 30 or 60 mg/kg body weight/day beginning 2 weeks before mating and continuing through gestation day 19. On gestation day 20, blood and livers were collected from the pregnant rats for analysis of hepatotoxicity endpoints: serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), glutathione (GSH) and glutathione S-transferase (GST), total microsomal P450, nuclear DNA damage and lipid peroxidation. Under these experimental conditions, no significant differences were observed in any of these biomarkers over the concentration range examined.