Organochlorine Pesticides Residues in Human Breast Milk from the Middle Governorates in Jordan in 2013/2014

One hundred samples of mother breast milk were gathered from six middle governorates and districts in Jordan in 2013/2014 to monitor Organochlorine pesticides pollutants. The results showed clearly that banned organochlorine pesticides are still detected in the monitored samples in low concentration despite banning of these persistent pollutants in Jordan since 36 years ago. However, the results indicated that 1% of the contaminated samples contained β-HCH, 5% γ-HCH, 3% p,p'-DDD, 2% heptachlor, 45% p,p'-DDE and 3% p,p'-DDT. In addition, these monitored samples had no residues of aldrin, dieldrin, α-endosulfan, β-endosulfan, HCB, o,p'-DD, o,p'-DDT and o,p'-DDE. In conclusion, there was a decline in the residues of Organochlorine pesticides, particularly DDT group members.

The adrenal specific toxicant mitotane directly interacts with lipid membranes and alters membrane properties depending on lipid composition

Mitotane (o,p'.-DDD) is an orphan drug approved for the treatment of adrenocortical carcinoma. The mechanisms, which are responsible for this activity of the drug, are not completely understood. It can be hypothesized that an impact of mitotane is mediated by the interaction with cellular membranes. However, an interaction of mitotane with (lipid) membranes has not yet been investigated in detail. Here, we characterized the interaction of mitotane and its main metabolite o,p'-dichlorodiphenyldichloroacetic acid (o,p'-DDA) with lipid membranes by applying a variety of biophysical approaches of nuclear magnetic resonance, electron spin resonance, and fluorescence spectroscopy. We found that mitotane and o,p'-DDA bind to lipid membranes by inserting into the lipid-water interface of the bilayer. Mitotane but not o,p'-DDA directly causes a disturbance of bilayer structure leading to an increased permeability of the membrane for polar molecules. Mitotane induced alterations of the membrane integrity required the presence of phosphatidylethanolamine and/or cholesterol. Collectively, our data for the first time characterize the impact of mitotane on the lipid membrane structure and dynamics, which may contribute to a better understanding of specific mitotane effects and side effects.

Association of mitotane with chylomicrons and serum lipoproteins: practical implications for treatment of adrenocortical carcinoma

OBJECTIVE

Oral mitotane (o,p'-DDD) is a cornerstone of medical treatment for adrenocortical carcinoma (ACC).

AIM

Serum mitotane concentrations >14  mg/l are targeted for improved efficacy but not achieved in about half of patients. Here we aimed at a better understanding of intestinal absorption and lipoprotein association of mitotane and metabolites o,p'-dichlorodiphenylacetic acid (o,p'-DDA) and o,p'-dichlorodiphenyldichloroethane (o,p'-DDE).

DESIGN

Lipoproteins were isolated by ultracentrifugation from the chyle of a 29-year-old patient and serum from additional 14 ACC patients treated with mitotane. HPLC was applied for quantification of mitotane and metabolites. We assessed NCI-H295 cell viability, cortisol production, and expression of endoplasmic reticulum (ER) stress marker genes to study the functional consequences of mitotane binding to lipoproteins.

RESULTS

Chyle of the index patient contained 197  mg/ml mitotane, 53  mg/ml o,p'-DDA, and 51  mg/l o,p'-DDE. Of the total mitotane in serum, lipoprotein fractions contained 21.7±21.4% (VLDL), 1.9±0.8% (IDL), 8.9±5.5% (LDL1), 18.9±9.6% (LDL2), 10.1±4.0% (LDL3), and 26.3±13.0% (HDL2). Only 12.3±5.5% were in the lipoprotein-depleted fraction.

DISCUSSION

Mitotane content of lipoproteins directly correlated with their triglyceride and cholesterol content. O,p'-DDE was similarly distributed, but 87.9±4.2% of o,p'-DDA found in the HDL2 and lipoprotein-depleted fractions. Binding of mitotane to human lipoproteins blunted its anti-proliferative and anti-hormonal effects on NCI-H295 cells and reduced ER stress marker gene expression.

CONCLUSION

Mitotane absorption involves chylomicron binding. High concentrations of o,p'-DDA and o,p'-DDE in chyle suggest intestinal mitotane metabolism. In serum, the majority of mitotane is bound to lipoproteins. In vitro, lipoprotein binding inhibits activity of mitotane suggesting that lipoprotein-free mitotane is the therapeutically active fraction.

The lack of antitumor effects of o,p'DDA excludes its role as an active metabolite of mitotane for adrenocortical carcinoma treatment

Mitotane (o,p'DDD) is the most effective treatment of advanced adrenocortical carcinoma (ACC) but its mechanism of action remains unknown. Previous studies suggested that o,p'DDA may represent the active metabolite of mitotane. We aimed at reevaluating the potential role and pharmacological effects of o,p'DDA. Functional consequences of o,p'DDA exposure were studied on proliferation, steroidogenesis, and mitochondrial respiratory chain in human H295R and SW13 adrenocortical cells. Mitotane and its metabolites were quantified using high-performance liquid chromatography combined to an ultraviolet detection in these cells treated with o,p'DDD or o,p'DDA and in human adrenal tissues. Dose-response curves up to 300 μM showed that, as opposed to o,p'DDD, o,p'DDA did not inhibit cell proliferation nor alter respiratory chain complex IV activity, gene expression nor induce mitochondrial biogenesis, oxidative stress, or apoptosis. However, whereas mitotane drastically decreased expression of genes involved in steroidogenesis, o,p'DDA slightly reduced expression of some steroidogenic enzymes and exerts weak anti-secretory effects only at high doses. While o,p'DDD concentration was significantly reduced by 40 % in H295R cell supernatants after 48 h incubation, o,p'DDA levels remained unchanged suggesting that o,p'DDA was not efficiently transported into the cells. o,p'DDA was not detected in cell homogenates or supernatants after 48 h exposure to o,p'DDD, consistent with the absence of o,p'DDA production in these models. Finally, unlike o'p'DDD, we found that o,p'DDA content was undetectable in two ACC and one normal adrenal gland of mitotane-treated patients, suggesting a lack of cellular uptake and in situ production. Our results demonstrate that o,p'DDD, but not o,p'DDA, induces functional alterations in adrenal cells.

Structural requirements for mitotane activity: development of analogs for treatment of adrenal cancer

AIM

Mitotane is used in adrenal cancer as adjuvant therapy, monotherapy or combined with other cytotoxic agents in advanced disease, but only 30% of patients respond. The aim of this study was to define the structural requirements for drug activity and to develop analogs with improved adrenalytic action.

MATERIALS AND METHODS

Nine analogs of [1-(2-chlorophenyl)-1-(4-chlorophenyl)-2,2dichloroethane] (o,p'-DDD) were tested by measuring suppression of cortisol secretion and the presence of inflammatory changes in the dog adrenal and inhibition of cell proliferation and cortisol production by NCI-H295 human adrenal cancer cells.

RESULTS

In addition to mitotane, o,p'-DDClBr and o,p'-DDBr(2), were active in vitro and in vitro: Their effects were comparable to that of o,p'-DDD when tested at 50 μM concentration, but o,p'DDBr(2) was significantly more active at the lower 20 μM concentration.

CONCLUSION

A dihalogenated methine carbon is required for adrenalytic activity. A change in the aromatic portion of the mitotane molecule causes loss of activity. Because of its greater activity at lower concentrations, o,p'-DDBr(2) has potential application in the treatment of patients with adrenal cancer.

Organochlorine pesticides and polychlorinated biphenyls in sediments and fish from freshwater cultured fish ponds in different agricultural contexts in north-eastern France

Organochlorine pesticides (HCB, HCH with α-, β-, and γ isomers, heptachlor, cis-heptachlor epoxyde, trans-heptachlor epoxyde, endosulfan with α- and β isomers, sulfate endosulfan, o,p'-DDT, p,p'-DDT, o,p'-DDE, p,p'-DDE, o,p'-DDD, p,p'-DDD, chlorothalonil, alachlor, aldrin, dieldrin, methoxychlor, oxychlordane, chlordane with α- and γ isomers, p,p'-dicofol and o,p'-dicofol) and indicators PCBs (IUPAC nos. 28, 52, 101, 118, 138, 153, and 180) were studied both in sediments and muscles of farmed fish species (Cyprinus carpio and Perca fluviatilis). Samples were collected from fish ponds located in the hydrographic basin of the Moselle River (Lorraine Region, France). OCPs and PCBs were present at low concentrations both in sediments and fish muscles. Concerning sediments, ∑DDTs revealed concentrations ranging from 0.2 to 2.30 ng g(-1) dw and ∑PCBs ranged from 0.3 to 3.5 ng g(-1) dw. Concerning fish muscles, the highest concentrations in OCPs were those of p,p'-DDE, with average concentrations of 0.57±0.44 ng g(-1) ww for carp and 0.58±0.29 ng g(-1) ww for perch. The contamination profiles proved to be different depending on the fish species. Indeed, HCH-isomers, HCB, and dieldrin were detected only for the carp and always at low concentrations. For example, the highest concentration of HCHs was observed for β-HCH with a mean value of 0.64±0.15 ng g(-1) ww for carp. As for PCBs, the levels of ∑PCBs ranged from 0.3 to 6.4 ng g(-1) ww in carp muscles and from 0.90 to 5.60 ng g(-1) ww in perch muscles.

Plasma concentrations of o,p'DDD, o,p'DDA, and o,p'DDE as predictors of tumor response to mitotane in adrenocortical carcinoma: results of a retrospective ENS@T multicenter study

CONTEXT

In patients with adrenocortical carcinoma (ACC) mitotane activity has been suggested to depend on plasma levels 14 mg/liter or greater and metabolite formation.

OBJECTIVE

The study was performed to confirm the correlation of the currently used mitotane (o,p'DDD) threshold of 14 mg/liter with tumor response and to evaluate the additional value of 1,1-(o,p'-dichlorodiphenyl) acetic acid (o,p'DDA) and o,p'DDE (1,1-(o,p'-dichlorodiphenyl)-2,2 dichloroethene) levels for predicting tumor response.

SUBJECTS/METHODS

Plasma samples collected within 3 months of best response from 91 patients on mitotane therapy for advanced ACC were analyzed retrospectively. O,p'DDD and metabolites were assessed and related to tumor response and survival. Receiver operating characteristic curves were used. Sensitivity and specificity were calculated for different cutoff levels of o,p'DDD and metabolites.

RESULTS

Objective tumor response was observed in 19% of patients. Median o,p'DDD level was higher in responders (P = 0.03). More responders were found among patients achieving o,p'DDD levels 14 mg/liter or greater (P = 0.02). Univariate and multivariate analysis showed significantly longer survival for patients with o,p'DDD levels 14 mg/liter or greater (hazard ratio 0.52, P = 0.04, hazard ratio 0.46, P = 0.03). An o,p'DDD cutoff value of 14 mg/liter was associated with a sensitivity of 65% and specificity 69%. An o,p'DDD level 20 mg/liter or greater or 14 mg/liter or greater combined with o,p'DDA level 92 mg/liter or greater was associated with a specificity of 90 and 92%, respectively.

CONCLUSIONS

Our data confirm the value of o,p'DDD plasma monitoring as well as targeting the 14 mg/liter cutoff level in the therapeutic management of ACC patients. Furthermore, our results suggest additional benefit of higher levels of o,p'DDD and combined measurement of o,p'DDD and o,p'DDA.

Synthesis of 2-(4-chlorophenyl)-2-(4-chloro-3-thiophenol)-1,1-dichloroethene (3-SH-DDE) via Newman-Kwart rearrangement - a precursor for synthesis of radiolabeled and unlabeled alkylsulfonyl-DDEs

For the first time, a pathway for synthesis of 2-(4-chlorophenyl)-2-(4-chloro-3-thiophenol)-1,1-dichloroethene (3-SH-DDE), is presented. The compound is of particular interest as a precursor for synthesis of alkylsulfonyl-DDE containing different alkyl groups to discover structural activity relationships, and to promote synthesis of radiolabeled methylsulfonyl-DDE. 2-Chloro-5-methylphenol was first methylated and further oxidized to the corresponding benzoic acid. The acid was reduced to the corresponding aldehyde (4-chloro-3-methoxy benzaldehyde) via 4-chloro-3-methoxy-benzene methanol. A lead/aluminium bimetal system was used to carry out the reductive addition of tetrachloromethane to 4-chloro-3-methoxy benzaldehyde to obtain 2,2,2-trichloro-1-(4-chloro-3-methoxyphenyl)ethanol, the desired starting material to synthesize the DDT-analogue (2-(4-chlorophenyl)-2-(4-chloro-3-methoxy-phenyl)-1,1,1-trichloroethane). Elimination of hydrochloric acid and removal of the methyl group led to the 3-OH-DDE. The Newman-Kwart rearrangement was applied to convert 3-OH-DDE to 3-SH-DDE via the dimethylcarbamothioate derivative. 3-SH-DDE is then used as a precursor for the radiolabel synthesis. The overall yield to acquire 3-SH-DDE after 11 steps was 3%. The step with the lowest yield was the DDT-analog synthesis with a yield of 30%. All other step had a yield of >50%. 3-SH-DDE was methylated with (14)C-labeled iodomethane and oxidized by hydrogen peroxide to obtain 3-[(14)C]MeSO(2)-DDE in an overall yield of 30%.

Effects of o,p'-DDE, heptachlor, and 17beta-estradiol on vitellogenin gene expression and the growth hormone/insulin-like growth factor-I axis in the tilapia, Oreochromis mossambicus

Effects of two endocrine disruptors, o,p'-DDE and heptachlor, and 17beta-estradiol (E(2)) on vitellogenin (Vg) and the growth hormone (GH)/insulin-like growth factor-I (IGF-I) axis were examined in male tilapia. In the first experiment, fish were given 5 weekly injections of either E(2), o,p'-DDE or heptachlor (5 microg/g). E(2) treatment increased plasma Vg and hepatic expression of three Vg genes (Vgs A, B, and C) and estrogen receptor alpha (ERalpha), while reducing plasma levels of IGF-I and suppressing the expression of IGF-I, the GH receptor (GHR2) and the putative somatolactin receptor (GHR1). Neither pesticide greatly affected the other parameters examined, except for a significant reduction in expression of GHR2 and increased plasma IGF-I. In the second experiment, fish were given a single injection of o,p'-DDE or heptachlor (100 microg/g), or E(2) (5 microg/g) and sacrificed 5 days post-injection. Treatment with E(2) stimulated expression of all three Vg genes. Both o,p'-DDE and heptachlor increased expression of VgB, whereas only o,p'-DDE increased VgA expression. There was no effect of o,p'-DDE or heptachlor on VgC expression or plasma Vg levels. Treatment with o,p'-DDE and heptachlor as well as E(2) increased ERalpha and ERbeta transcript levels. Similarly, both pesticides increased GHR1 and IGF-I expression, whereas no significant effect of E(2) was observed on GHR1, GHR2 or IGF-I expression. These results indicate that o,p'-DDE and heptachlor have varying temporal and dose effects on modulation of Vg and the GH/IGF-I axis that are distinct from E(2).

DDT- and DDE-induced disruption of ovarian steroidogenesis in prepubertal porcine ovarian follicles: a possible interaction with the main steroidogenic enzymes and estrogen receptor beta

We evaluated impact of DDT isomers, o, p'- DDT [1, 1-dichloro-2, 2-bis (p, p'-chlorophenyl) ethylene] and p, p'-DDT [1, 1, 1-trichloro-2, 2-bis (p-chlorophenyl) ethane], and their metabolites, o, p'-DDE and p, p'-DDE, on ovarian steroidogenesis. All these compounds, except for p, p'-DDT, demonstrated estrogenic effects on steroid secretion in co-cultures of porcine prepubertal granulosa and theca cells. p,p'-DDT decreased progesterone and estradiol release, which was reversed by the addition of testosterone. In contrast, o, p'-DDT inhibited progesterone secretion with parallel stimulation of basal and testosterone-stimulated estradiol release. DDEs stimulated progesterone and estradiol secretion. The fluorometric assay confirmed that p,p'-DDE, o,p'-DDT, and o,p'-DDE stimulated aromatase activity. Western blots indicated that o,p-DDT and o,p'-DDE diminished the expression of estrogen receptor beta (ERbeta). This study demonstrated the isomer-dependent action of DDT in pig ovarian cells. We propose that DDT could disrupt ovarian steroidogenesis either by interfering with main steroidogenic enzymes or affecting ERbeta.

Rapid effects of pesticides on human granulosa-lutein cells

Following our previous demonstration that p,p'-DDE (dichlorodiphenylchloroethylene), at environmentally relevant concentrations, can rapidly increase intracellular calcium [Ca2+]i concentrations in human granulosa-lutein cells, we examined whether other pesticides, such as Kepone, o,p-DDE and methoxychlor, have similar effects. Cultured human granulosa-lutein cells were loaded with Fura-2 AM, and changes in [Ca2+]i concentrations within small areas of single cells were studied with a dynamic digital Ca2+ imaging system. Kepone, at concentrations of 0.2-2 nmol/ml, consistently increased [Ca2+]i concentrations 2-6 times higher than baseline values within minutes of exposure. Methoxychlor at concentrations of 2.8-280 nmol/ml failed to alter [Ca2+]i levels consistently in cells from 10 patients. However, at 0.28 and 1.4 nmol/ml, increases in [Ca2+]i concentrations could be elicited by methoxychlor. The isomer o,p-DDE at 3 nmol/ml increased [Ca2+]i in granulosa cells of 11/20 patients. Pertussis toxin treatment inhibited the [Ca2+]i increases induced by estradiol, p,p'-DDE, o,p-DDE and methoxychlor, but not by Kepone or progesterone, indicating that Kepone and progesterone may act through an insensitive G protein-coupled receptor. The [Ca2+]i increases induced by Kepone also occurred in Ca2+-free medium, suggesting that [Ca2+]i mobilization occurred from the smooth endoplasmic reticulum. Thapsigargin and cyclopiazonic acid, two inhibitors of the endoplasmic reticulum Ca2+ pump, also stimulated [Ca2+]i increases but did not inhibit the Ca2+ response to all the pesticides. These results demonstrate that pesticides can have a rapid effect on human granulosa-lutein cells, and a nongenomic mechanism of action is suggested.

Clinical role of determination of plasma mitotane and its metabolites levels in patients with adrenal cancer: results of a long-term follow-up

Our study aimed at evaluation of the relations between the plasma levels of mitotane (o,p'-DDD) and its metabolites, o,p'-DDA and o,p'-DDE, and the efficacy of Mitotane therapy during a long-term follow-up. Eighteen patients, aged 11 to 70 years, were included to the study. Metastatic or regional stage was diagnosed in 15 patients, while localized disease in three patients. Mitotane has been administered in daily doses of 3.0 to 10.0 g in metastatic and regional stages, and 1.5 to 4.0 g in the localized disease, simultaneously with hydrocortisone, prednisolone and fludrocortisone. Mitotane and its metabolites were determined by a high-pressure liquid chromatographic method. The plasma o,p'-DDD level exceeding 44 _M/L, considered as curative one, was reached in nine cases. The o,p'-DDA/o,p'-DDD ratio rose significantly mainly in the first 1-3 months of therapy. The o,p'-DDE levels rose slowly, reaching higher values in long-term therapy, over 12 months of mitotane administration. In the group of patients with regional or metastatic stage, both the o,p'-DDE levels and the o,p'-DDE/o,p'-DDD ratios were higher in the survivors than in non-survivors. The results of our study suggest that the plasma concentrations of o,p'-DDE were more closely related to clinical improvement or remission than the o,p'-DDD levels.

Effect of single and repeated in vitro exposure of ovarian follicles to o,p'-DDT and p,p'-DDT and their metabolites

The aim of the presented study was to compare the effect of o,p'-DDT [1,1-dichloro-2,2-bis-(p,p'-chlorophenyl)-ethylene] and p,p'-DDT [1,1,1-trichloro-2,2-bis-(p-chlorophenyl)-ethane] and their metabolites DDE and DDD on estradiol secretion by ovarian follicles, the target organs of environmental estrogens. Theca interna (Tc) and granulosa cells (Gc) were collected from medium size porcine follicles and cultured as a monolayer. The cells were initially cultured for 24 h to allow attachment to the plates and then media were changed for the new ones and o,p'-DDT and p,p'-DDT and their metabolites: o,p'-DDE, p,p'-DDE and o,p'-DDD were added at doses of 4, 40, 400 ng and 4 microg/ml medium to investigate dose-dependent effects. Media were collected after 24 h and frozen for estradiol content determination. When the effect of single and repeated exposure was investigated, the lowest dose of 4 ng/ml and the highest one of 4 microg/ml were chosen on the basis of the results of Experiment 1. o,p'-DDT exerted antiestrogenic action at all doses used while its metabolites and p,p'-DDT and its metabolites decreased estradiol secretion only when present in the medium at a dose of 4 ng/ml. The highest doses caused the increase in estradiol secretion. Parent o,p'-DDT and its metabolites showed antiestrogenic action after single exposure to 4 ng/ml while parent p,p'-DDT and its metabolites caused estrogenic action. All investigated compounds, except o,p'-DDT, increased estradiol secretion after single exposure to the dose of 4 microg/ml. Repeated exposure resulted in a massive antiestrogenic action of all investigated chemicals. In conclusion, our study points to time-dependent effect of DDT and its metabolites on ovarian follicles with the strongest estrogenic properties observed after single exposure and antiestrogenic action caused by repeated exposure. Given the duration of folliculogenesis, one can imagine many different potential mechanisms by which DDT could influence steroidogenesis.

Toxicity of o,p'-DDE to medaka d-rR strain after a one-time embryonic exposure by in ovo nanoinjection: an early through juvenile life cycle assessment

The toxicity of o,p'-DDE (1,1-dichloro-2-(p-chlorophenyl)-2-(o-chlorophenyl) ethylene) was evaluated in embryos of medaka (Oryzias latipes) following a one time exposure via nanoinjection. Medaka eggs (early gastrula) were injected with 0.5 nl of triolein (vehicle control) or 0.5 nl of 4 graded doses (0.0005-0.5 ng/egg) of o,p'-DDE in triolein. Embryos were allowed to develop, and fry were reared. Embryonic survival was monitored daily during the first 10 d until hatching and thereafter, on a weekly basis until day 59, at which time the fish were monitored for sexual maturity until day 107. In general, o,p'-DDE caused a dose- and time-dependent mortality. No changes in mortality were observed between the last two time points (day 38 and 59, respectively), and hence a 59 day-LD50 of 346 ng o,p'-DDE/egg was derived from the linear dose-response relationship. Prior to late stage death, only isolated cases of cardiovascular lesions and spinal deformities were observed, but were not dose-dependent. The lowest observable adverse effect level (LOAEL), based on upper 95% CI for regression line=0.0018 mg/kg, and the LOAEL based on exposure doses=0.5 mg/kg. Likewise, the no observable adverse effect level (NOAEL) based on linear extrapolation to 100% survival=0.0000388 mg/kg, while the NOAEL based on exposure doses=0.05 mg/kg. The nanoinjection medaka model has potential in the study of hormonally active compounds in the environment.

Short-term exposure of Chinook salmon (Oncoryhnchus tshawytscha) to o,p-DDE or DMSO during early life-history stages causes long-term humoral immunosuppression

We evaluated the effect of short-term exposures to a xenobiotic chemical during early life-history stages on the long-term immune competence of chinook salmon (Oncoryhnchus tshawytscha). Immersion of chinook salmon eggs in a nominal concentration of o,p-dichlorodiphenyldichloroethylene (o,p-DDE; 10 ppm) for 1 hr at fertilization followed by immersion in the same dose for 2 hr at hatch resulted in a significant reduction in the ability of splenic leukocytes from fish 1 year after treatment to undergo blastogenesis upon in vitro stimulation with lipopolysaccharide. We also observed that the vehicle, dimethyl sulfoxide (DMSO), caused a significant reduction in the ability of the splenic leukocytes to express surface immunoglobin M (SIgM) at this time. The concentration of o,p-DDE in a pooled sample of whole fry from this treatment was 0.53 microg/g lipid 1 month after first feeding but was undetectable in all other treatments. Mortality rate, time to hatch, fish length, and weight were unaffected by treatment with o,p-DDE. Similarly, sex ratios, gonadal development, and concentrations of plasma estradiol and 11-ketotestosterone were not affected by the treatment. In addition, we found no evidence that plasma lysozyme concentrations or the mitogenic responses of splenic leukocytes to concanavalin A or polyinosinic-polycytidylic acid were influenced by the treatment. In this experiment, a brief period of exposure to o,p-DDE or DMSO during early development was able to induce long-term effects on humoral immune competence of chinook salmon. Such immunosuppression may increase susceptibility to disease, which may in turn be critical to regulating the population.

In ovo exposure to o,p -DDE affects sexual development but not sexual differentiation in Japanese medaka (Oryzias latipes)

Despite being banned in many countries, dichlorodiphenyltrichloroethane (DDT) and its metabolites dichlorodiphenyldichloroethylene (DDE) and dichlorodiphenyldichloroethane (DDD) continue to be found in fish tissues at concentrations of concern. Like o,p -DDT, o,p -DDE is estrogenic and is believed to exert its effects through binding to the estrogen receptor. The limited toxicologic data for o,p -DDE suggest that it decreases fecundity and fertility of fishes. We conducted an egg injection study using the d-rR strain of medaka and environmentally relevant concentrations of o,p -DDE to examine its effects on sexual differentiation and development. The gonads of exposed fish showed no evidence of sex reversal or intersex. However, other gonad abnormalities occurred in exposed individuals. Females exhibited few vitellogenic oocytes and increased atresia. Male testes appeared morphologically normal but were very small. Gonadosomatic index values for both sexes were lower for exposed fish. Our observations of abnormal female and very small male gonads after in ovo o,p -DDE exposure may be indicative of effects on early endocrine processes important for normal ovarian and testicular development.

Conventional and novel strategies in the treatment of adrenocortical cancer

Adrenocortical carcinoma is a highly malignant neoplasm with an incidence of two per million people per year. Several treatment strategies have resulted in temporary or partial tumor regression but very few cases have attained long survival. Surgical resection of the primary tumor and metastases is most effective. Several chemotherapeutic protocols have been employed with variable success. Mitotane (o,p'-DDD) is an adrenalytic drug effective in inducing a tumor response in 33% of patients treated. Mitotane requires metabolic transformation for therapeutic action. Tumors may vary in their ability to metabolize mitotane and the ability of tumors to transform mitotane may predict the clinical response to the drug. Preliminary data show a possible correlation between metabolic activity of neoplastic adrenocortical tissue and response to mitotane. We have attempted to develop mitotane analogs with enhanced adrenalytic effect. Compared to mitotane, a di-chloro compound, the bromo-chloro and di-bromo analogs appear to have a greater effect. Future approaches to the treatment of adrenocortical carcinoma are likely to be based on blocking or reversing the biological mechanisms of tumorigenesis. Angiogenic and chemotactic mechanisms may play a role in adrenal tumor growth and inhibition of these mechanisms may result in inhibition of tumor growth. New mitotane analogs with greater adrenalytic potential could be a promising approach to developing more effective and selective therapies for adrenal cancer. Alternative approaches should attempt to suppress tumor growth by means of compounds with anti-angiogenic and anti-chemotactic activity.

Detection of endocrine disrupting chemicals in samples of second trimester human amniotic fluid

Man-made chemicals that have been shown to modulate endocrine function in animal models, so-called "endocrine disrupters", are suspected to play a role in the development of male reproductive tract abnormalities and neurobehaviroal deficits in children. However in utero exposure to environmental contaminants has not been documented previously. The present study was performed to test our hypothesis that man-made chemicals can be quantified in human amniotic fluid during the second trimester. Gas chromatographic/mass spectrometric (GC/MS) analysis was performed on amniotic fluid samples (n=53) from women (n=51) undergoing routine amniocentesis with a mean (+/- SEM) age of 36.5 +/- 0.5 years and between 15 and 23 weeks of gestation. Analytes included common PCB congeners, the DDT metabolites p,p'-DDE, and o,p'-DDE as well as the pesticides: hexachlorobenzene (HCB); and the three isomers of hexachlorocyclohexane (alpha,beta and gamma-HCH). The limit of quantitation (LOQ) for PCBs was 0.01 ng/ml and for the other organochlorines contaminants is was 0.1 ng/ml. The contaminants alpha-HCH with a mean (+/- SD) concentration of 0.15 +/- 0.06 (ng/ml) and p,p'-DDE with a mean (+/- SD) concentration of 0.21 +/- 0.18 ng/ml were detected in the amniotic fluid. PCB specific congeners were detected with a much lower frequency and levels were in the range of the LOQ. Overall one in three amniotic fluid samples tested positive for at least one environmental contaminant. Therefore, we conclude that approximately one in three fetuses in the Los Angeles area are exposed to endocrine modulatory environmental contaminants in utero the consequences of which remain unknown at this time.

Salmonid sexual development is not consistently altered by embryonic exposure to endocrine-active chemicals

Fish sexual development is sensitive to exogenous hormone manipulation, and salmonids have been used extensively as environmental sentinels and models for biomedical research. We simulated maternal transfer of contaminants by microinjecting rainbow trout (Oncorhynchus mykiss) and chinook salmon (Oncorhynchus tshawytscha) embryos. Fish were reared for 6 months and sexed, and gonads were removed for histology and measurement of in vitro steroid production. Analysis of fat samples showed that dichlorodiphenylethylene (DDE) levels, o, p'M-DDE and p,o, p'-DDE isomers, were elevated 6 months after treatment. A preliminary study showed an increased ratio of males to females after treatment with 80 mg/kg and 160 mg/kg of the xenoestrogen o,o, p'-DDE. One fish treated with 160 mg/kg o,o, p'-DDE had gonads with cells typical of both males and females. A follow-up study, using more fish and excluding the highly toxic 160 mg/kg o,o, p'-DDE dose, showed no effect on sex ratio or gonadal histology. Embryonic exposure of monosex male trout, monosex female trout, and mixed sex salmon to o, o, p'-DDE, p,o, p'-DDE, mixtures of DDE isomers, and octylphenol failed to alter sexual development. We observed no treatment-dependent changes in in vitro gonadal steroid production in any experiments. Trout exposed in ovo and reared to maturity spawned successfully. These results suggest that mortality attributable to the xenoestrogens o,o, p'-DDE, chlordecone, and octylphenol, and the antiandrogen p,o, p'-DDE, is likely to occur before the appearance of subtle changes in sexual development. Because trout appeared to be sensitive to endocrine disruption, we cannot dismiss the threat of heavily contaminated sites or complex mixtures to normal sexual development of salmonids or other aquatic organisms.

Reporter cell lines to study the estrogenic effects of xenoestrogens

In order to characterize the estrogenic activity of chemicals, we established complementary in vitro recombinant receptor-reporter gene assays in stably transfected MCF-7 and HeLa cells. MCF-7 cells which express the endogenous estrogen receptor alpha (ER alpha) were stably transfected with only an estrogen-regulated luciferase gene. These cells enable the detection of compounds which bind to ER alpha or interfere with the induction of ER alpha mediated gene expression. Furthermore, HeLa cells, which do not express endogenous ERs, were transfected with an ER alpha or an ER beta construct together with an estrogen-regulated luciferase gene, or a chimeric GAL4-ER alpha receptor and the corresponding luciferase reporter gene. Finally, we tested these four cellular models as tools to check the estrogenic activities of several potential xenoestrogens and to detect estrogenic activity in wastewater sewage treatment effluents. In all of the models, nonylphenol mixture (NPm), 4n-nonylphenol (4nNP), 2,4'-DDE, 4,4'-DDE and wastewater sewage treatment effluent were active, while PCB mixture (Aroclor 1254), PCB 77, atrazine and lindane (gamma hexachlorocyclohexane) were inactive. Dioxin partially activates the estrogen receptor in MCF-7 cells while in HeLa-derived cell lines, it decreased the estrogenic-induced expression of luciferase.

Determination of mitotane (o,p-DDD) and its metabolites o,p-DDA and o,p-DDE in plasma by high-performance liquid chromatography

The adrenolytic agent mitotane (o,p'-DDD or 1,1-(o,p'-dichlorodiphenyl)-2,2-dichoroethane) is believed to be metabolically activated, resulting in the generation of reactive intermediates or the formation of o,p'-DDA. A new high-performance liquid chromatographic (HPLC) method for measurement of mitotane and two of its metabolites, o,p'-DDA (1,1-(o,p'-dichlorodiphenyl) acetic acid) and o,p'-DDE (1,1-(o,p'-dichlorodiphenyl)-2,2 dichloroethene), in plasma has been developed. Sample preparation involves precipitation of plasma proteins with acetone before chromatographic separation under isocratic conditions on a silica-based diphenyl column. Mitotane and metabolites are quantified by ultraviolet detection at 218 nm. Recoveries for the three compounds range between 99% and 110%, with between-day and within-day coefficients of variation <6% within the therapeutic range. Limits of detection are 0.5 microM and the assay is linear up to at least 800 microM for o,p'-DDA and 100 microM for mitotane and o,p'-DDE. The method has been evaluated using samples from three patients on mitotane therapy, revealing o,p'-DDA levels in plasma 3 to 10 times higher than the levels of the parent compound.

Bovine adrenal cortex transformations of mitotane [1-(2-chlorophenyl)-1-(4-chlorophenyl)-2,2-dichloroethane; o,p'-DDD] and its p,p'- and m,p'-isomers

The adrenalytic activity of mitotane (o,p'-DDD) has made it useful in the treatment of adrenocortical carcinoma and Cushing's syndrome. In support of a study to develop mitotane analogs as more effective therapeutic agents and as a basis for understanding the toxicity of related compounds in the adrenals, the biotransformations of o,p'-DDD in adrenocortical homogenate preparations have been studied and compared with those of its m,p'- and p,p'-isomers. Aliphatic oxidation to the corresponding acetic acid derivative, o,p'-, m,p'- or p,p'-DDA, was the major transformation for all the preparations. In the comparisons of the DDD isomers, the order of both DDA formation and apparent covalent binding was o,p'- > m,p'- > p,p'-DDD. There was also evidence for alpha-hydroxylation at the benzylic carbon with subsequent loss of water to form ethylene derivatives. This was a minor pathway for o,p'-DDD, but was the major pathway for the other two isomers. Thus, while the total yields of metabolites of o,p'- and m,p'-DDD were similar and at least twice that of the p,p'-isomer, their distribution of metabolites differed significantly. The effects of the three isomers on cell growth and cortisol production with the human adrenocortical carcinoma cell line, NCI H-295, followed the same order as their DDA formation and tissue binding. It is proposed that hydroxylation by the adrenal cortex at the beta-carbon leads to an adrenalytic effect, whereas hydroxylation at the alpha-carbon would represent an alternate deactivation pathway.

Comparison of the adrenalytic activity of mitotane and a methylated homolog on normal adrenal cortex and adrenal cortical carcinoma

Mitotane is an important adrenalytic drug for the treatment of adrenal cancer whose use is limited by toxicity. Reports from another laboratory indicated that a methylated homolog of Mitotane (Mitometh) tested in guinea pigs possessed comparable adrenalytic activity but was less toxic than Mitotane. This observation prompted us to undertake a comparative study of these two drugs on the basis that Mitometh may be a superior agent for the treatment of adrenal cancer. Preliminary studies in guinea pigs failed to show a significant adrenalytic effect for either Mitotane or Mitometh. Thus, we extended the study to 13 mongrel dogs weighing 12-15 kg that were treated daily with Mitometh or Mitotane (50-100 mg/kg) for 6 or 12 days. Cortisol decreased to undetectable levels and adrenocorticotropic hormone (ACTH) rose to 10 times the baseline levels within 72 h in Mitotane-treated animals. Despite the achievement of similar drug levels, Mitometh treatment in dogs failed to suppress cortisol or increase ACTH. To determine whether these differences were due to differences in bioavailability, we measured the relative concentration of Mitotane and Mitometh in homogenates of adrenal cortex obtained from Mitotane- and Mitometh-treated dogs. The adrenal concentration of Mitometh determined in Mitometh-treated dogs was 5 times higher than the concentration of Mitotane measured in Mitotane-treated animals. Whereas the adrenal glands of Mitotane-treated dogs showed hemorrhage and necrosis, the Mitometh-treated animals showed no adrenal damage. Despite the lack of adrenalytic activity, Mitometh maintained its toxicity as demonstrated by microscopic evidence of hepatic necrosis and an increase in hepatic enzymes. The adrenalytic effects of both agents was also studied in vitro using a human functioning adrenal cortical carcinoma cell line, NCI-H295. Whereas Mitotane strongly suppressed cell growth, Mitometh had a weaker effect. We conclude that Mitometh is not likely to be effective in the therapy of adrenal cancer. Moreover, the results of this study are supportive of the view that metabolic transformation of Mitotane is in some way linked to its adrenalytic action.

Noninvasive in vivo 13C-NMR spectroscopy in the rat to study the pharmacokinetics of 13C-labeled xenobiotics

Noninvasive NMR methodology has been developed to enable monitoring of 13C-labeled xenobiotics in the rat in vivo. 2,2-Dichloro-1-(2-chlorophenyl)-1-(4-chlorophenyl)-[3-13C]-propane can be detected in the liver of intact rats by in vivo 13C surface coil NMR spectroscopy after ip administration of the compound. The experiments were performed at 1.9 and 9.4 Tesla. The intrahepatic changes of the signal intensity of the labeled compound were followed as a function of time. In the days following administration, the concentration decreased and dropped to values below the detection limit after 12 days. The study demonstrates the feasibility of studies on pharmacokinetics of 13C-labeled compounds in the rat using noninvasive, in vivo surface coil NMR spectroscopy in animals. The sensitivity allows the detection of a single dose of the drug of 200 mg/kg, but can be improved.

Noninvasive in vivo 13C-NMR spectroscopy of a 13C-labeled xenobiotic in the rat

This study demonstrates that the xenobiotic product, 1-(o-chlorophenyl)-1-(p-chlorophenyl)-2,2-dichloro-3-13C-propane can be monitored in the liver of an intact animal by in vivo 13C surface coil NMR spectroscopy after intraperitoneal administration. The carbon-13 label could be detected after a single dose of only 200 mg/kg of the product. The intrahepatic changes of the signal intensity of the labeled product were monitored as a function of time. No signals corresponding to metabolites could be detected.

Plasma level monitoring of mitotane (o,p'-DDD) and its metabolite (o,p'-DDE) during long-term treatment of Cushing's disease with low doses

Mitotane (o,p'-DDD) can be used for the treatment of various adrenocortical diseases such as Cushing's syndrome, but the usual doses of 6-8 g per day are often associated with severe adverse effects. This paper reports the results of much lower doses of o,p'-DDD (0.5-2 g per day) in two patients with Cushing's disease over periods of 8 and 5 years, respectively, under concomitant monitoring of the plasma levels of the parent drug and its major metabolite, o,p'-DDE. It became apparent that o,p'-DDD and o,p'-DDE have a strong tendency to accumulate in the body due to their high lipophilicity. As a consequence, changes in dose regimens had long lag times before they were reflected in plasma levels and once an increase or decrease had started one had to be careful not to cause overshoot. Steady state plasma levels of o,p'-DDD between 5-10 micrograms/ml appeared sufficient to induce and to maintain remission of the disease, which was accompanied with normal cortisol levels in plasma and urine. DDD-levels below 5 micrograms/ml for several weeks may lead to relapses, whereas DDD-levels over 10 micrograms/ml gave rise to side effects. On the other hand, o,p'-DDE seemed inactive at levels up to 4 micrograms/ml in plasma.

Use of GC/MS/SIM for rapid determination of plasma levels of o,p'-DDD, o,p'-DDE and o,p'-DDA

A new method for extraction and quantification of plasma o,p'-DDD (2,2-(2-chlorophenyl,4'-chlorophenyl)1,1-dichloroethane) and its metabolites has been developed. When plasma (0.1 ml) adsorbed to and dried on a filter paper was heated with 5% hydrogen chloride in methanol (1 ml) in a boiling water bath, o,p'-DDD and its metabolites were liberated from the serum protein and were able to be easily extracted with benzene. The recovery rate was raised compared with conventional methods. In addition, this procedure also carried out the simultaneous methylation of o,p'-DDA, one of the metabolites. Mass numbers of 199, 210, 235 and 246 were selected from the mass spectra of o,p'-DDD and its related substances, and they were monitored. Identification was performed on the basis of the retention time and the mass peak intensity ratio. Quantitative determination was performed using the internal standard technique. It was learned that o,p'-DDA is present in the plasma at a concentration about 10 times higher than the levels of o,p'-DDD and o,p'-DDE.

Toxicity, ultrastructural effects, and metabolic studies with 1-(o-chlorophenyl)-1-(p-chlorophenyl)-2,2-dichloroethane(o,p'-DDD) and its methyl analog in the guinea pig and rat

Effects of 1-(o-chlorophenyl)-1-(p-chlorophenyl)-2,2-dichloroethane (o,p'-DDD) (Lysodren; Mitotane) (I) and 1-(o-chlorophenyl)-1-(p-chlorophenyl)-2, 2-dichloropropane (Mitometh) (II) were investigated. Ultrastructural and toxicity studies were conducted with male Hartley outbred guinea pigs given 300 mg/kg/day ip for 14 days. Profound mitochondrial damage in the guinea pig adrenal cortex, an index of Lysodren's action as a cancer chemotherapeutic, reversible necrosis of the zona fasciculata and zona reticularis with swelling, disrupted cristae, and organelles destroyed in the mitochondria from these areas. Yet guinea pigs given Mitometh tolerated the drug better than those given an equivalent amount of Lysodren. In general the animals treated with Mitometh showed less alopecia, diarrhea, and weakness. The only deaths recorded in our study were in the Lysodren group. In addition po administration of these two drugs to male Sprague-Dawley rats and male Hartley guinea pigs for 4 days allowed for a direct comparison of urinary metabolites. Metabolites were identified from urine extracts by computerized mass spectrometry interfaced with capillary gas chromatography. Both compounds were shown to undergo dehydrohalogenation and side-chain cleavage to a limited extent; however, only Lysodren afforded side-chain oxidation metabolites. In fact, the dominant metabolite from Lysodren biotransformation was the corresponding carboxylic acid o,p'-DDA (III). On the other hand, Mitometh resisted side-chain oxidative metabolism and was less toxic than Lysodren. Therefore, when given to guinea pigs and rats, Mitometh had Lysodren-like biologic activity, did not undergo rapid inactivation, and was less toxic than Lysodren. Mitometh represents a potential alternative to Lysodren which should be investigated further for its possible use in the treatment of adrenal cortical carcinoma and Cushing's syndrome.

The role of high density lipoproteins in the biodistribution of two radioiodinated probes in the rat

Two radioiodinated probes, 125I-cholesteryl oleate (125I-CO), a derivative of a natural constituent of lipoproteins, and 1-(2-chlorophenyl)-1-(4[125I]iodophenyl)-2,2-dichlorethane (125I-DDD), an analog of the adrenolytic drug o,p'-DDD (mitotane), were selected to study the role of lipoproteins in drug disposition and to examine the ability of these vehicles to direct foreign molecules to specific tissues. In vivo and in vitro techniques were utilized to associate these probes with rat high density lipoproteins (HDL). Tissue distribution studies indicated that prior incorporation of 125I-CO into rat HDL increased the uptake of 125I-CO by rat adrenal, which was dramatically enhanced when this preparation was administered to animals made hypolipidemic with 4-aminopyrazolo(3,4-d)-pyrimidine (4-APP). Acetylation of HDL labeled with 125I-CO provided evidence that the observed uptake into the adrenal was via a receptor-mediated process. In contrast with these results, prior association of 125I-DDD with rat HDL failed to alter the ability of this compound to accumulate in adrenal tissue of normal or hypolipidemic animals. Polyacrylamide gel electrophoresis (PAGE) was utilized to examine the stability of the association of 125I-CO and 125I-DDD with rat HDL. These results suggested that 125I-CO was associated with the lipophilic core of HDL, whereas 125I-DDD appeared to be partially associated with the surface components of HDL. Saturation of surface components with stable o,p'-DDD offered data to suggest that this binding to apoproteins may disrupt the normal receptor-mediated uptake process. These studies indicate that lipoproteins may effect the distribution and tissue uptake of lipophilic compounds and, conversely, lipophilic molecules can effect the metabolic fate of lipoproteins. The overall result is dependent upon the nature of the association of these lipophilic compounds with lipoproteins which is difficult to predict on the basis of molecular structure alone.

Cytotoxic activity of 1-(o-chlorophenyl)-1-(p-chlorophenyl)-2,2-dichloroethane (mitotane) and its analogs on feminizing adrenal neoplastic cells in culture

Mitotane [1-(o-chlorophenyl)-1-(p-chlorophenyl)-2,2-dichloroethane], an antineoplastic agent for inoperable adrenal carcinoma, was studied for its cytotoxic activity on a clonal line of feminizing human adrenal neoplastic cells (Fang-8 cells) in culture. At concentrations higher than 1.68 X 10(-4) M, mitotane produced a dose-related toxic effect on the cells. The effect of the drug was specific to Fang-8 cells because the same treatment produced little or no toxicity on lines of rat pituitary GH3 cells and human skin fibrocytes. The effect of mitotane to Fang-8 cells was a reversible one. Electron microscopic pictures revealed that the drug was causing mitochondrial degeneration. In this testing system, several isomers and analogs of mitotane were found equally or more toxic than was mitotane itself. The dichloro- or trichloroethylene structure was essential for the cytotoxic activity while the chloro substituents on phenyl rings appeared to be unimportant. This system appears to be useful in elucidating the biochemical mechanism of mitotane action on adrenal cancer.

[Effect of O,N'=dichlorodiphenyldichloroethane and pertan in vitro on glutathione reductase activity in the adrenals of dogs and guinea pigs]

Glutathione reductase is activated by o,p'-dichlorodiphenyldichlorethane (o,p'-DDD) and pertan added in a concentration of 312 micrometer to the homogenate and cytoplasmic fraction of the dog adrenals. At a concentration of 156 micrometer o,p'-DDD and pertan failed to influence the glutathione reductase activity of the dog adrenal glands. Added in vitro, o,p'-DDD and pertan activate glutatione reductase of the quinea pig adrenal glands. O,p'-DDD does not affect the glutathione reductase activity of the liver and kidney cytoplasmic fraction in dogs. This observation confirms the high specificity of o,p'-DDD action on the adrenal glands.

[Activity of glutathione reductase in the adrenal glands and the liver of dogs after administration O,P-DDD, perthane and ACTH]

A study was made of the inhibitors of the adrenal gland function and ACTH on the activity of NADP-specific glutathionreductase in the adrenal glands and the liver of dogs. After a 10-day feeding to dogs of o,p'-dichlordiphenyldichlorethane (o,p'-DDD) and p,p'-diethyldiphenyl dichlorethane (p,p'-pertane) in a dose of 50 mg/kg there was observed a marked activation of glutathion reductase in the adrenal glands. Elevation of the activity of the enzyme was revealed as soon as 24 hours after the administration of o,p'-DDD. The inhibitors under study failed to influence the activity of the enzyme in the liver of dogs, this indicating a specific action of o,p'-DDD and pertane on the adrenal gland cortex. Stimulation of glucocorticoid biosynthesis under the effect of ACTH administered once in a dose of 25 Units/kg was not accompanied by the changes in the activity of glutathione reductase in the adrenal glands and the liver of dogs. Prolonged ACTH administration (4 Units/kg) caused a significant reduction of the enzyme activity calculated as per 1 mg of protein in the adrenal gland homogenate.