Alteration of steroidogenesis in H295R cells by organic sediment contaminants and relationships to other endocrine disrupting effects

Identification of AhR agonists in sediments of the Bohai and Yellow Seas using advanced effect-directed analysis and in silico prediction

Novel aryl hydrocarbon receptor (AhR) agonists were identified in coastal sediments in the Yellow and Bohai Seas by use of a combination of effect-directed analysis (EDA) and in silico prediction. A total of 125 sediments were screened for AhR-mediated potencies using H4IIE-luc bioassay. Great potencies were observed in organic extracts, mid-polar fraction (F2), and subfractions of F2 (F2.6-F2.9) of sediments collected from Nantong, Qinhuangdao, and Yancheng. Less than 15% AhR potencies could be explained by detected dioxin-like PAHs. Full-scan screening analysis was conducted for the more potent fractions using GC-QTOFMS to investigate the presence of unmonitored AhR agonists. A five-step prioritization strategy was applied; 92 candidate compounds satisfied all criteria. Among these chemicals, thirteen were evaluated for AhR efficacy. Six compounds; benz[b]anthracene, 6-methylchrysene, 2-methylbenz[a]anthracene, 1-methylbenz[a]anthracene, 1,12-dimethylbenzo[c]phenanthrene, and indeno[1,2,3-cd]fluoranthene, exhibited significant AhR-mediated efficacies. 1,12-dimethylbenzo[c]phenanthrene and indeno[1,2,3-cd]fluoranthene were identified as novel AhR agonists. Potency balance analysis showed that the six newly identified AhR agonists explained 0.4-100% of the total AhR-mediated potencies determined. Overall, combining EDA and in silico prediction applied in this study demonstrated the benefits of assessing the potential toxic effects of previously unidentified AhR agonists in sediments from the coasts of China and Korea.

Congenital Adrenal Hyperplasia-Current Insights in Pathophysiology, Diagnostics, and Management

Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive disorders affecting cortisol biosynthesis. Reduced activity of an enzyme required for cortisol production leads to chronic overstimulation of the adrenal cortex and accumulation of precursors proximal to the blocked enzymatic step. The most common form of CAH is caused by steroid 21-hydroxylase deficiency due to mutations in CYP21A2. Since the last publication summarizing CAH in Endocrine Reviews in 2000, there have been numerous new developments. These include more detailed understanding of steroidogenic pathways, refinements in neonatal screening, improved diagnostic measurements utilizing chromatography and mass spectrometry coupled with steroid profiling, and improved genotyping methods. Clinical trials of alternative medications and modes of delivery have been recently completed or are under way. Genetic and cell-based treatments are being explored. A large body of data concerning long-term outcomes in patients affected by CAH, including psychosexual well-being, has been enhanced by the establishment of disease registries. This review provides the reader with current insights in CAH with special attention to these new developments.

Removal efficiencies and risk assessment of endocrine-disrupting chemicals at two wastewater treatment plants in South China

Endocrine-disrupting chemicals (EDCs) in the effluent from wastewater treatment plants (WWTPs) are an important pollutant sources of the aquatic system. In this study, the removal efficiencies of eight typical EDCs at two domestic WWTPs in Dongguan City, China, are reported based on instrumental analysis and bioassay results. Bioactivities, including steroidogenesis-disrupting effects, estrogen receptor (ER)-binding activity, and aryl hydrocarbon receptor (AhR)-binding activity were evaluated using the H295R, MVLN, and H4IIE cell bioassays, respectively. The potential environmental risks of these residual EDCs were also evaluated. The results of instrumental analysis showed that nonylphenol was the major chemical type present among the eight tested EDCs. Meanwhile, concentrations of estrogen compounds including estrone, 17β-estradiol (E2), estriol, 17α-ethinyl estradiol, and diethylstilbestrol were relatively low. The removal rates of all eight EDCs were relatively high. Although the chemical analysis indicated high removal efficiency, the bioassay results showed that steroidogenesis-disrupting effects as well as ER-binding and AhR-binding activities remained, with E2-equivalent values of effluent samples ranging from 0.16 to 0.9 ng·L^-1, and 2,3,7,8-tetrachlorodibenzo-p-dioxin-equivalent values ranging from 0.61 to 4.09 ng L^-1. Principal component analysis combined with regression analysis suggests that the chemicals analyzed in this study were partly responsible for these ER and AhR activities. Ecological risk assessment of the residual EDCs showed that estrone was the most hazardous chemical among the eight EDCs tested, with a risk quotient of 1.44-5.50. Overall, this study suggests that, despite high apparent removal efficiencies of typical EDCs, their bioactivities and potential ecological risks cannot be ignored.

Lactational polychlorinated biphenyls exposure induces epigenetic alterations in the Leydig cells of progeny rats

The present study was designed to establish the epigenetic mechanisms by which lactational exposure to PCBs affects the Leydig cell function in progeny rats. The lactating dams were oral gavaged with different doses of PCBs [1, 2 and 5 mg/kg or corn oil ] and Leydig cells were isolated from the testes of progeny rats at postnatal day (PND) 60. We assessed the expression of transcription factors regulating steroidogenic machinery and the promoter methylation of LHR and AR in the Leydig cells. Our results confirmed hypermethylation of SF-1, Sp1/3, LHR and AR genes. There was a significant reduction in the gene expression of SF-1 and Sp1. The mRNA expression of Sp3 was decreased. Interestingly, there was an increased gene expression levels of DNA methyltransferases (Dnmts) (Dnmt1, Dnmt3a/b and Dnmt3l) and unaltered histone deacetylase-1 (Hdac-1). Furthermore, increased percentage of 5-methylcytosine was observed in PCBs exposed Leydig cells. Taken together, our findings suggest that promoter hypermethylation of SF-1, Sp1/3, LHR and AR could have led to transcriptional repression of these genes in Leydig cells. In conclusion, our study demonstrates that lactational exposure to PCBs caused epigenetic changes in the Leydig cells which could have impaired the Leydig cell function in progeny (PND60) rats.

Human cytochrome P450 enzymes 5-51 as targets of drugs and natural and environmental compounds: mechanisms, induction, and inhibition - toxic effects and benefits

Cytochrome P450 (P450, CYP) enzymes have long been of interest due to their roles in the metabolism of drugs, pesticides, pro-carcinogens, and other xenobiotic chemicals. They have also been of interest due to their very critical roles in the biosynthesis and metabolism of steroids, vitamins, and certain eicosanoids. This review covers the 22 (of the total of 57) human P450s in Families 5-51 and their substrate selectivity. Furthermore, included is information and references regarding inducibility, inhibition, and (in some cases) stimulation by chemicals. We update and discuss important aspects of each of these 22 P450s and questions that remain open.

Assessing the effects of Awba dam sediment (Nigeria) on the steroidogenesis of H295R cells using different extraction methods

In the present study, H295R human cells were used to investigate the endocrine disruptor potential of three different sediments extracts taken from a Nigerian tropical freshwater dam (Awba Dam), using three extraction methods that allowed a selective consideration of contaminants based on their binding affinity, which is mainly driven by polarity, to sediment particles. After exposure to different concentration of each extract, H295R cells were evaluated for the expression profiles of 10 steroidogenic enzyme genes and estradiol (E2) and testosterone (T) levels. Our results showed a comparable concentrated-related increase in the expression of 17β-hsd1, 3β-hsd2 and cyp21 in cells treated with the polar and non-polar extracts. The star, hmgr, cyp11b2 and 17β-hsd4 were slightly decreased, in an apparent concentration-specific manner, after treatment with the polar extract and decreased in the non-polar treatment. The cyp11a and cyp17 showed an opposite trend in the polar and non-polar treatments. E2 was significantly higher in cell treated with the non-polar extract. Elutriate exposure produced less pronounced variation in mRNA and hormones levels. Overall the extract with non-polar compounds produced the most severe effects in H295R cells. Thus, direct ingestion of detritus and mud from fishes and other benthonic organisms represent possible transfer of contaminants in the trophic web, and mainly account for alteration of the endocrine system previously observed in fish from the same study site.

Co-culture of JEG-3, BeWo and syncBeWo cell lines with adrenal H295R cell line: an alternative model for examining endocrine and metabolic properties of the fetoplacental unit

Monocultures of different placental cells are used for many physiological and toxicological studies; however, they are not a true reflection of the interaction between placenta and fetus. To develop the most appropriate model to study endocrine and metabolic properties of fetoplacental unit we used three co-culture models of placental cells nonfusogenic JEG-3, unsyncytialised BeWo (BeWo) and syncytialised BeWo (syncBeWo) cultured with adrenal (H295R) cells. As an end point of endocrine properties we investigated steroids receptors expression and steroid secretion, while as metabolic properties AhR, CYP1A1and COMT expression. Progesterone (P4), estradiol (E2) and human chorionic gonadotropin (hCG) secretion (ELISA) and 3βHSD, CYP19, estrogen (ERα/β), progesterone (PR) and aryl hydrocarbon (AhR) receptors, CYP1A1 and COMT protein expression (Western blot) were evaluated. Comparing three co-culture models we observed: (1) there were no differences between JEG-3 and BeWo in the PR expression, however it was higher in BeWo compared to syncBeWo; (2) there were no differences in ERα protein expression in all models, while profile of ERβ expression was the highest in syncBeWo; (3) high P4 secretion in JEG-3 and BeWo while low in syncBeWo; (4) high E2 levels in JEG-3 and syncBeWo, while low E2 secretion in BeWo; (5) the highest hCG secretion in the JEG-3 and syncBeWo than in BeWo (6) the highest AhR, CYP1A1 and COMT expression in syncBeWo. Based on the results showing higher hCG secretion in the JEG-3 than in BeWo, representing villous and extravillous phenotype we suggest that JEG-3 model could be used to study fetoplacental steroidogenesis at the 1st, while BeWo model at the 3rd. Results showing comparable profiles of AhR, CYP1A1 and COMT expression in JEG-3 and BeWo models and the significantly higher expression in synBeWo points to synBeWo as a good model for study the metabolic properties.

Endocrine disrupting potential of PAHs and their alkylated analogues associated with oil spills

Polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs are known to be major toxic contaminants in spills of petroleum hydrocarbons (oil). Spilled oil undergoes weathering and over time, PAHs go through a series of compositional changes. PAHs can disrupt endocrine functions, and the type of functions affected and associated potencies vary with the type and alkylation status of PAH. In this study, the potential of five major PAHs of crude oil, i.e., naphthalene, fluorene, dibenzothiophene, phenanthrene, and chrysene, and their alkylated analogues (n = 25), to disrupt endocrine functions was evaluated by use of MVLN-luc and H295R cell lines. In the MVLN-luc bioassay, seven estrogen receptor (ER) agonists were detected among 30 tested PAHs. The greatest ER-mediated potency was observed for 1-methylchrysene (101.4%), followed by phenanthrene and its alkylated analogues (range of %-E2max from 1.6% to 47.3%). In the H295R bioassay, significantly greater syntheses of steroid hormones were observed for 20 PAHs. For major PAHs and their alkylated analogues, disruption of steroidogenesis appeared to be more significant than ER-mediated effects. The number and locations of alkyl-moieties alone could not explain differences in the types or the potencies of toxicities. This observation shows that disruption of endocrine functions by some constituents of oil spills could be underestimated if only parent compounds are considered in assessments of hazard and risk.

Adrenocortical endocrine disruption

The adrenal has been neglected in endocrine disruption regulatory testing strategy. The adrenal is a vital organ, adrenocortical insufficiency is recognised in life threatening "adrenal crises" and Addison's disease, and the consequences of off-target toxicological inhibition of adrenocortical steroidogenesis is well recognised in clinical medicine, where drugs such as aminoglutethimide and etomidate killed patients via unrecognised inhibition of adrenocortical steroidogenic enzymes (e.g. CYP11B1) along the cortisol and aldosterone pathways. The consequences of adrenocortical dysfunction during early development are also recognised in the congenital salt wasting and adrenogenital syndromes presenting neonatally, yet despite a remit to focus on developmental and reproductive toxicity mechanisms of endocrine disruption by many regulatory agencies (USEPA EDSTAC; REACH) the assessment of adrenocortical function has largely been ignored. Further, every step in the adrenocortical steroidogenic pathway (ACTH receptor, StAR, CYP's 11A1, 17, 21, 11B1, 11B2, and 3-hydroxysteroid dehydrogenase Δ4,5 isomerase) is known to be a potential target with multiple examples of chemicals inhibiting these targets. Many of these chemicals have been detected in human and wildlife tissues. This raises the question of whether exposure to low level environmental chemicals may be affecting adrenocortical function. This review examines the omission of adrenocortical testing in the current regulatory frameworks; the characteristics that make the adrenal cortex particularly vulnerable to toxic insult; chemicals and their toxicological targets within the adrenocortical steroidogenic pathways; the typical manifestations of adrenocortical toxicity (e.g. human iatrogenically induced pharmacotoxicological adrenal insufficiency, manifestations in typical mammalian regulatory general toxicology studies, manifestations in wildlife) and models of adrenocortical functional assessment. The utility of the in vivo ACTH challenge test to prove adrenocortical competency, and the H295R cell line to examine molecular mechanisms of steroidogenic pathway toxicity, are discussed. Finally, because of the central role of the adrenal in the physiologically adaptive stress response, the distinguishing features of stress, compared with adrenocortical toxicity, are discussed with reference to the evidence required to claim that adrenal hypertrophy results from stress rather than adrenocortical enzyme inhibition which is a serious adverse toxicological finding. This article is part of a special issue entitled 'Endocrine disruptors and steroids'.

In vitro and in vivo toxicities of sediment and surface water in an area near a major steel industry of Korea: endocrine disruption, reproduction, or survival effects combined with instrumental analysis

The influence of industrial and/or municipal contaminant inputs on the aquatic environment of Pohang, Korea was investigated, with a focus on bioassay combined with instrumental analysis. Pohang is the most heavily populated city in Gyeongsangbuk-do province of Korea, with more than half a million residents, and also hosts the nation's biggest steel manufacturer and related industries. Sediment (n=15) and surface water samples (n=17) were collected from Hyeongsan River which runs across the Pohang city, in two separate events, i.e., June 2010 and February 2011. Sediment samples were first Soxhlet-extracted (raw extract) and were measured for estrogenicity using H295R cell line, and also analyzed for alkylphenols (APs), bisphenol A (BPA), PAHs, and PCBs. For sediment samples which exhibited greatest effects in the cell line, further fractionation was performed into non-polar, mid-polar, and polar portions. In surface water samples, heavy metals were also analyzed. Among 15 sediment samples, station S2 near the steel industry complex and station M3 near the municipal area showed the greatest sex hormone changes, and these changes were generally explained by the fractions which contained APs and BPA. Principal component analysis (PCA) however suggests that chemicals that were not analyzed in the present study would better explain endocrine disruption capacity of sediments. In water samples, adverse effects on hatchability and growth of Japanese medaka fish, and on Daphnia reproduction were noted following exposure to six water samples collected from stations near industrial and municipal areas. Several heavy metals and nonylphenol (NP) concentrations exceeded surface water quality guidelines, suggesting adverse effects of contamination inputs from both industrial and municipal activities. Observed estrogenicities in stations such as S2 and M3 warrant further investigations on longer term ecosystem impacts near industrial and municipal areas. The levels of major organic chemicals in sediments are quite comparable to those reported in ~10 years ago, emphasizing a need for source control.

Dioxin-like activity in sediments from Tai Lake, China determined by use of the H4IIE-luc bioassay and quantification of individual AhR agonists

Deterioration of the general ecosystem and specifically quality of the water in Tai Lake (Ch: Taihu), the third largest freshwater in China, is of great concern. However, knowledge on status and trends of dioxin-like compounds in Tai Lake was limited. This study investigated AhR-mediated potency and quantified potential aryl hydrocarbon receptor (AhR) agonists in sediments from four regions (Meiliang Bay, Zhushan Lake, Lake Center, Corner of Zhushan Lake, and Meiliang Bay) of Tai Lake by use of the in vitro H4IIE-luc, cell-based, transactivation, reporter gene assay, and instrumental analysis. Concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (Bio-TEQs) in sediments ranged from less than the limit of detection to 114.5 pg/g, dry weight, which indicated that organic extracts of sediments exhibited significant AhR-mediated potencies. Results of the potency balance analysis demonstrated that acid-labile, dioxin-like compounds represented a greater proportion of concentrations of Bio-TEQs in sediments from Tai Lake. Concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents calculated as the sum of the product of concentrations of individual congeners and their respective relative potencies (Chem-TEQs) based on polycyclic aromatic hydrocarbons and/or polychlorinated biphenyls represented no more than 10% of the total concentrations of Bio-TEQs.

Effects of polycyclic musks HHCB and AHTN on steroidogenesis in H295R cells

1,3,4,6,7,8-Hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-(γ)-2-benzopyran (HHCB) and 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene (AHTN) are widely used in personal care products. Previous studies showed that HHCB and AHTN can be found in various environmental matrices and have potential endocrine disrupting effects. However, the effects on adrenocortical function of HHCB and AHTN are not fully understood. This study evaluated the influences of HHCB and AHTN on seven steroid hormones (progesterone, aldosterone, cortisol, 17α-OH-progesterone, androstenedione, 17β-estradiol, and testosterone) and 10 genes involved in steroidogenic pathways (HMGR, StAR, CYP11A1, 3βHSD2, CYP17, CYP21, CYP11B1, CYP11B2, 17βHSD, and CYP19) using the H295R cell line in the absence and presence of 8-Br-cAMP. MC2R transcription on the cell membrane was also examined to further investigate the effects of HHCB and AHTN on adrenal steroidogenesis. The results demonstrated that HHCB and AHTN could inhibit progesterone and cortisol production mainly by the suppression of 3βHSD2 and CYP21. Meanwhile, high concentrations of AHTN can affect the sensitivity of H295R cells to ACTH by disrupting MC2R transcription. Overall, the results indicate that high concentrations of HHCB and AHTN can affect steroidogenesis in vitro using the H295R cell line.

Levels and profiles of PCDD/Fs, PCBs in mothers' milk in Shenzhen of China: estimation of breast-fed infants' intakes

Sixty breast milk samples were collected in Shenzhen, China from July to November in 2007. The samples were analyzed of the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs). The range of upper-bound for ∑TEQ-(PCDD/Fs+PCBs) in the samples was 4.10-35.3 pg TEQ g(-1) lipid (median: 10.6 pg TEQ g(-1) lipid; mean: 11.9 pg TEQ g(-1) lipid). The levels of the measured contaminants in the breast milk had significant correlations with the length of inhabitation period in Shenzhen (r=0.487, p<0.05 for PCDD/Fs, r=0.431, p<0.05 for PCBs and r=0.478, p<0.05 for ∑TEQ-(PCDD/Fs+PCBs)), and the consumption rate of fish (r=0.366, p<0.05 for PCDD/Fs, r=0.486, p<0.05 for PCBs and r=0.416, p<0.05 for ∑TEQ-(PCDD/Fs+PCBs)), respectively. Moreover, significant positive correlations were also detected between the participant's age (r=0.305, p<0.05 for ∑TEQ-PCBs and r=0.275, p<0.05 for ∑TEQ-(PCDD/Fs+PCBs)) and the body burdens of these contaminants respectively. It is estimated that the daily intake (EDI) of the sum of PCDD/Fs and DL-PCBs by the breast-fed infants was 5.60-161 pg TEQ kg(-1) bw per day (mean: 48.2 pg TEQ kg(-1) bw per day; median: 42.2 pg TEQ kg(-1) bw per day). The result showed that both the body burdens of PCDD/Fs and PCBs of the recruit population and the calculated EDI of the breast-fed infants were higher than those in the non-exposed areas in mainland China. This suggests that continuous surveillance on PCDD/Fs and PCBs levels in human milk is critical to more precisely evaluate the human health risk posed by the negative environmental impact in Shenzhen in the future.

A case of Intersexuality in the Parthenogenetic Marmorkrebs (Decapoda: Astacida: Cambaridae)

We describe an intersex specimen of the Marmorkrebs, the only obligate parthenogenetic freshwater crayfish with an all-female population. The individual was a fully functional female which possessed male-like first pleopods. Nevertheless, it reproduced successfully and the offspring were normally developed parthenogenetic females, lacking any trace of male traits. The general rarity of aberrant sexual traits in freshwater crayfishes, in particular in Procambarus, is discussed. We suggest that a dysfunction of the sex determining system, which controls the anlagen of the androgenic glands during development, caused the partial male-like phenotype of this Marmorkrebs specimen. The application of this organism for investigations of sex determination and differentiation is recommended.

Modulation of estrogen synthesis through activation of protein kinase A in H295R cells by extracts of estuary sediments

Sediments from two estuaries within Liaodong Bay, China, were examined for the effects on steroidogenesis using H295R human adrenocortical carcinoma cells. Total extracts (TE) isolated from sediments by Soxhlet extraction were separated into three fractions (F1, F2, and F3) using Florisil columns. After exposing H295R cells to each TE and fractions, the expressions of six steroidogenic genes (cytochrome P450 cholesterol side-chain cleavage [CYP11A], 3β-hydroxysteroid dehydrogenase type 1 [3β-HSD1], 3β-hydroxysteroid dehydrogenase type 2 [3β-HSD2], cytochrome P450 17-hydroxylase/17-20 lyase [CYP17], cytochrome P450 aromatase [CYP19], 17β-hydroxysteroid dehydrogenase [17β-HSD]), and the production of six steroid hormones (progesterone [PGT], 17-hydroxyprogesterone [17-HPT], testosterone [TTR], androstenedione [ADD], estrone [E1], and 17β-estradiol [17β-E2]) were measured. The gene expressions of CYP11A, CYP17, 3β-HSD2, and CYP19, and hormone productions of PGT, 17-HPT, TTR, ADD, E1, and 17β-E2 were significantly increased after exposure to F3 extracts from the Daliao River. In particular, greater concentrations of E1 (up to 48-fold) and 17β-E2 (up to 20-fold), as well as up-regulation of CYP19 gene expression (up to tenfold), were caused by exposure to the F3 fraction from the Daliao River, but not from the Daling River. Insight into the mechanism of action was obtained by use of principal component analysis (PCA), the results of which were consistent with unidentified constituents in F3 from the Daliao River activating the protein kinase A (PKA) pathway. This hypothesis was confirmed by reversal of the effects caused by F3 through a co-exposure of a PKA inhibitor (H89) and F3 extract. The H89 down-regulated CYP19 messenger RNA (mRNA) expression with concomitant lesser production of E1 and 17β-E2 in the co-exposure group, indicating unidentified constituents that could modulate estrogen synthesis, primarily through a mechanism of PKA activation.

Genotoxicity and endocrine-disruption potentials of sediment near an oil spill site: two years after the Hebei Spirit oil spill

The Hebei Spirit oil spill episode (December 7, 2007) has affected the western coastal area of South Korea; however, there is limited information on the potential toxicity of the oil spill to the ecosystem or humans. The potential toxicity of sediments collected from the affected area (n = 22) 2 years after the spill was evaluated. Acute lethal toxicity tests using Vibrio fischeri and Moina macrocopa and tests for genotoxicity and alteration of steroidogenesis using chicken DT40 cells and H295R cells, respectively, were conducted. Both crude and weathered oil extracts were evaluated in order to link the observed toxicity in the sediment extracts to the oil spill. Whereas toxicity to bacteria and daphnids was observed in only two elutriate samples, 10 of the 22 sediment extracts showed genotoxic potential in DT40 cells. The mechanisms of genotoxicity involved nucleotide excision repair (XPA(-/)), homologous recombination (RAD54(-/-)), and translesion synthesis pathways (REV3(-/-)). In addition, nine sediment extracts caused significantly greater production of E2 in H295R cells, and significant up-regulation of CYP19, CYP11B2, and 3βHSD2 by sediment extracts was observed. The pattern of toxicities observed in both crude and weathered oil samples was similar to that observed in the sediment extracts. The genotoxicicity and endocrine-disruption potential of the sediment extracts suggest a need for long-term followup for such toxicity in humans and wildlife in this area.

Effects of mixtures of persistent organic pollutants (POPs) derived from cod liver oil on H295R steroidogenesis

Crude cod liver oil and liver oil supplements are consumed as a source of vitamin A, D and polyunsaturated fatty acids; during winter and early pregnancy. Crude cod liver oil however constitutes a considerable source of persistent organic pollutants (POPs). This paper aimed at characterizing and quantifying the influence of POP mixtures extracted from three different steps in the cod liver oil industrial process on hormone production and the expression of steroidogenesis-related genes in H295R cells. Exposure to extracts from crude cod liver oil and from its industrial waste increased progesterone (P4), cortisol (Cort), testosterone (T) and estradiol (E2) production; and among others, the expression of MC2R, CYP11B1 and HSD3B2 genes. Observed effects after exposure to pharmaceutical cod liver oil extract were considerably lower. The type of effects on gene expression and hormone production were similar to those induced by forskolin and PCBs, the latter being the major contaminants within the extracts. Additional research is required to further unveil the mechanisms behind the observed steroidogenic effects and to assess whether the potential risk might outweigh the potential benefits of crude and processed cod liver oil consumption.

In vitro steroidogenic effects of mixtures of persistent organic pollutants (POPs) extracted from burbot (Lota lota) caught in two Norwegian lakes

This study investigated the effects of two mixtures of persistent organic pollutants (POPs) on steroidogenesis in the H295R cell line. The two mixtures were obtained from the livers of burbot (Lota lota) caught in two Norwegian lakes (Mjøsa and Losna) with different contaminant profiles. Steroid hormone levels in the cell culture medium and mRNA levels of 16 genes involved in steroidogenesis were investigated. The crude Lake Mjøsa extract had to be diluted ten times more than the Lake Losna extract in order to prevent cytotoxicity. The ten times diluted Lake Mjøsa mixture had higher levels of DDT and derivates (∑DDTs, 1.7 times) and brominated flame retardants (∑BDEs and HBCD, 15-25 times) than the Lake Losna mixture, which, on the other hand, had higher concentrations of ∑PCBs (1.5 times higher) and also of HCB, ∑HCH isomers and ∑chlordane isomers (5-20 times higher). In the cell culture media, only cortisol levels were increased at the highest exposure concentration to the Lake Mjøsa mixture, while both cortisol and estradiol levels were increased following exposure to the two highest Lake Losna mixture exposure concentrations. Testosterone levels decreased only at the highest exposure concentration of the Lake Losna mixture. Multivariate models suggested that ∑PCBs, and to a lesser extent ∑DDTs, were responsible for the cortisol responses, while estradiol and testosterone alterations were best explained by HCB and ∑PCBs, respectively. Exposure to the mixtures generally increased mRNA levels, with smaller effects exerted by the Lake Mjøsa mixture than the Lake Losna mixture. It was concluded that both mixtures affected steroidogenesis in the H295R cells. Small differences in mixture composition, rather than the high content of brominated flame retardants in the Lake Mjøsa mixture, were suggested to be the most probable reason for the apparent differences in potencies of the two mixtures.

The endocrine disrupting potential of sediments from the Upper Danube River (Germany) as revealed by in vitro bioassays and chemical analysis

INTRODUCTION

The present study was part of a comprehensive weight-of-evidence approach with the goal of identifying potential causes for the declines in fish populations, which have been observed during the past decades in the Upper Danube River.

METHODS

The specific goal was the investigation of the endocrine disrupting potential of sediment extracts from different sites along the Danube River. Parallel to the identification and quantification of target estrogens, two in vitro bioassays were employed to assess the estrogenic potential (yeast estrogen screen, YES) of the sediment samples and to evaluate their effects on the production of testosterone (T) and E2 (H295R Steroidogenesis Assay). Using a potency balance approach, the contribution of the measured compounds (Chem-EEQs) to the total endocrine activity measured by the YES (YES-EEQs) was calculated.

RESULTS AND DISCUSSION

Of the nine sediment extracts tested five extracts exhibited significant estrogenic activities in the YES, which suggested the presence of ER agonists in these samples. The xenoestrogens nonylphenol (NP) and bisphenol A (BPA) and the natural estrogen estrone (E1) were detected while concentrations of 17β-estradiol (E2) and ethinylestradiol (EE2) were less than their respective limits of quantification in all sediment extracts. A comparison of the measured YES-EEQs and the calculated Chem-EEQs revealed that as much as 6% of estrogenic activity in extracts of most sediments could be explained by two xeno- and one natural estrogen. Exposure of H295R cells to sediment extracts from four different locations in the Danube River resulted in significantly increased concentrations of E2, but only slight inhibition of T synthesis. Furthermore, application of the H295R Steroidogenesis Assay provided evidence for endocrine disrupting potencies in sediment samples from the Upper Danube River, some of which were not detectable with the YES. In conclusion, differential endocrine activities were associated with several sediments from the Upper Danube River. Further investigations will have to show whether the observed activities are of biological relevance with regard to declines in fish populations in the Upper Danube River.

Endocrine potency of wastewater: contents of endocrine disrupting chemicals and effects measured by in vivo and in vitro assays

Industrial and municipal effluents are important sources of endocrine disrupting compounds (EDCs) discharged into the aquatic environment. This study investigated the endocrine potency of wastewater and the cleaning efficiency of two typical urban Danish sewage treatment plants (STPs), using chemical analysis and a battery of bioassays. Influent samples, collected at the first STP grate, and effluent samples, collected after the sewage treatment, were extracted using solid phase extraction. Extracts were analyzed for the content of a range of industrial chemicals with endocrine disrupting properties: phthalate metabolites, parabens, industrial phenols, ultraviolet screens, and natural and synthetic steroid estrogens. The endocrine disrupting bioactivity and toxicity of the extracts were analyzed in cell culture assay for the potency to affect the function of the estrogen, androgen, aryl hydrocarbon, and thyroid receptors as well as the steroid hormone synthesis. The early-life stage (ELS) development was tested in a marine copepod. The concentrations of all analyzed chemicals were reduced in effluents compared with influents, and for some to below the detection limit. Influent as well as effluent samples from both STPs were found to interact with all four receptors and to interfere with the steroid hormone synthesis showing the presence of measured EDCs. Both influent samples and one of the effluent samples inhibited the development of the copepod Acartia tonsa. In conclusion, the presence of EDCs was reduced in the STPs but not eliminated, as verified by the applied bioassays that all responded to the extracts of effluent samples. Our data suggest that the wastewater treatment processes are not efficient enough to prevent contamination of environmental surface waters.

Three structurally different polychlorinated biphenyl congeners (Pcb 118, 153, and 126) affect hormone production and gene expression in the human H295R in vitro model

Polychlorinated biphenyls (PCB) are ubiquitous environmental pollutants that have been linked to adverse health effects including endocrine disruption. This study compared the mono-ortho-substituted PCB 118 and di-ortho-substituted PCB 153 with the non-ortho-substituted PCB 126, for possible effects on steroid hormone production and on the expression of 10 genes encoding proteins involved in steroidogenesis. The H295R human adenocarcinoma cell line was used as an in vitro model. Cells were exposed for 48 h to solvent control (dimethyl sulfoxide, DMSO) or 6 different concentrations ranging from 40 pM to 4 muM of one of the three test compounds. All three congeners significantly increased the production of estradiol-17beta. PCB 118 produced a rise in progesterone and cortisol in a concentration-dependent manner, similar to PCB 126. Testosterone was significantly reduced in response to PCB 153 but not PCB 118 or PCB 126. All three congeners elevated aldosterone at the highest concentration tested. A significant increase was observed in CYP11B2 mRNA levels in cells exposed to the three congeners. In addition, PCB 126 upregulated CYP19, 3beta-HSD2, StAR, and HMGR mRNA levels at the highest concentration tested, and downregulated CYP21 at 40 nM. In conclusion, all three PCB congeners are capable of modulating steroidogenesis in H295R in a concentration-dependent manner, whereby the hormone profile following PCB 118 exposure resembles that of PCB 126. Where changes in gene expression profile are concerned, exposure to PCB 126 showed the greatest effects.

Modulation of steroidogenesis by coastal waters and sewage effluents of Hong Kong, China, using the H295R assay

BACKGROUND, AIM, AND SCOPE

The presence of a variety of pollutants in the aquatic environment that can potentially interfere with the production of sex steroid hormones in wildlife and humans has been of increasing concern. The aim of the present study was to investigate the effects of extracts from Hong Kong marine waters, and influents and effluents from wastewater treatment plants on steroidogenesis using the H295R cell bioassay. After exposing H295R cells to extracts of water, the expression of four steroidogenic genes and the production of three steroid hormones were measured.

MATERIALS AND METHODS

Water samples were collected during the summer of 2005 from 24 coastal marine areas and from the influents and effluents of two major waste water treatment plants (WWTPs) in Hong Kong, China. Samples were extracted by solid phase extraction (SPE). H295R cells were exposed for 48 h to dilutions of these extracts. Modulations of the expression of the steroidogenic genes CYP19, CYP17, 3betaHSD2, and CYP11beta2 were determined by measuring mRNA concentrations by real-time polymerase chain reaction (Q-RT-PCR). Production of the hormones progesterone (P), estradiol (E2), and testosterone (T) was quantified using enzyme linked immunosorbent assays (ELISA).

RESULTS

Extracts from samples collected in two fish culture areas inhibited growth and proliferation of H295R cells at concentrations greater or equal to 10(5) L equivalents. The cells were exposed to the equivalent concentration of active substances in 10,000 L of water. Thus, to observe the same level of effect as observed in vitro on aquatic organisms would require a bioaccumulation factor of this same magnitude. None of the other 22 marine samples affected growth of the cells at any dilution tested. Twelve of the marine water samples completely inhibited the expression of CYP19 without affecting E2 production; inhibition of CYP17 expression was observed only in one of the samples while expression of CYP11beta2 was induced as much as five- and ninefold after exposure of cells to extracts from two locations. The expression of the progesterone gene 3betaHSD2 was not affected by any of the samples; only one sample induced approximately fourfold the production of E2. Although more than twofold inductions were observed for P and T production, none of these values were statistically significant to conclude effects on the production of these two hormones. While influents from WWTPs did not affect gene expression, an approximately 30% inhibition in the production of E2 and a 40% increase in P occurred for the exposure with influents from the Sha Tin and Stonecutters WWTPs, respectively. Effluents from WWTPs did not affect the production of any of the studied hormones, but a decrement in the expression of the aldosterone gene CYP11beta2 was observed for the Sha Tin WWTP exposure. No direct correlation could be established between gene expression and hormone production.

DISCUSSION

Observed cytotoxicity in the two samples from fish culture areas suggest the presence of toxic compounds; chemical analysis is required for their full identification. Although effluents from WWTPs did not affect hormone production, other types of endocrine activity such as receptor-mediated effects cannot be ruled out. Interactions due to the complexity of the samples and alternative steroidogenic pathways might explain the lack of correlation between gene expression and hormone production results.

CONCLUSIONS

Changes observed in gene expression and hormone production suggest the presence in Hong Kong coastal waters of pollutants with endocrine disruption potential and others of significant toxic effects. The aromatase and aldosterone genes seem to be the most affected by the exposures, while E2 and P are the hormones with more significant changes observed. Results also suggest effectiveness in the removing of compounds with endocrine activity by the WWTPs studied, as effluent samples did not significantly affect hormone production. The H295R cell showed to be a valuable toll in the battery required for the analysis of endocrine disrupting activities of complex environmental samples.

RECOMMENDATIONS AND PERSPECTIVES

Due to the intrinsic complexity of environmental samples, a combination of analytical tools is required to realistically assess environmental conditions, especially in aquatic systems. In the evaluation of endocrine disrupting activities, the H295R cell bioassay should be used in combination with other genomic, biological, chemical, and hydrological tests to establish viable modes for endocrine disruption and identify compounds responsible for the observed effects.

Activities and identification of aryl hydrocarbon receptor agonists in sediments from the Danube river

This study is a consequence of a distinct fish decline in the Danube river since the beginning of the 1990s. In contrast to the decline of fish population, former studies have repeatedly documented that the water quality along the Danube river is improving. However, the conclusion of a pilot study in 2002 was that a high hazard potential is associated with local sediments. The present study documents that sediment samples from the Danube river showed comparatively high aryl hydrocarbon receptor mediated activity in biotests, using the cell lines GPC.2D.Luc, H4IIE (DR-CALUX) and RTL-W1. The combination of chemical analysis, fractionation techniques and different in vitro tests revealed that priority pollutants could not explain the main induction, even though the concentrations of priority polycyclic aromatic hydrocarbons (PAHs) were very high (maximum in the tributary Schwarzach, sum of 16 EPA PAHs 26 mug/g). In conclusion, this investigation shows that nonpriority pollutants mainly mediate the high induction rates. Nevertheless, owing to the effects of PAHs towards fish and the connection between dioxin-like activity and carcinogenicity, the link between contamination and the fish population decline cannot be ruled out.

Adrenal toxicology: a strategy for assessment of functional toxicity to the adrenal cortex and steroidogenesis

The adrenal is the most common toxicological target organ in the endocrine system in vivo and yet it is neglected in regulatory endocrine disruption screening and testing. There has been a recent marked increase in interest in adrenal toxicity, but there are no standardised approaches for assessment. Consequently, a strategy is proposed to evaluate adrenocortical toxicity. Human adrenal conditions are reviewed and adrenocortical suppression, known to have been iatrogenically induced leading to Addisonian crisis and death, is identified as the toxicological hazard of most concern. The consequences of inhibition of key steroidogenic enzymes and the possible toxicological modulation of other adrenal conditions are also highlighted. The proposed strategy involves an in vivo rodent adrenal competency test based on ACTH challenge to specifically examine adrenocortical suppression. The H295R human adrenocortical carcinoma cell line is also proposed to identify molecular targets, and is useful for measuring steroids, enzymes or gene expression. Hypothalamo-pituitary-adrenal endocrinology relevant to rodent and human toxicology is reviewed (with an emphasis on multi-endocrine axis effects on the adrenal and also how the adrenal affects a variety of other hormones) and the endocrinology of the H295R cell line is also described. Chemicals known to induce adrenocortical toxicity are reviewed and over 60 examples of compounds and their confirmed steroidogenic targets are presented, with much of this work published very recently using H295R cell systems. In proposing a strategy for adrenocortical toxicity assessment, the outlined techniques will provide hazard assessment data but it will be regulatory agencies that must consider the significance of such data in risk extrapolation models. The cases of etomindate and aminoglutethimide induced adrenal suppression are clearly documented examples of iatrogenic adrenal toxicity in humans. Environmentally, sentinel species, such as fish, have also shown evidence of adrenal endocrine disruption attributed to exposure to chemicals. The extent of human sub-clinical adrenal effects from environmental chemical exposures is unknown, and the extent to which environmental chemicals may act as a contributory factor to human adrenal conditions following chronic low-level exposures will remain unknown unless purposefully studied.