Determination of selected herbicides and phenols in water and soils by solid-phase extraction and high-performance liquid chromatography. (1/14)

A high-performance liquid chromatography procedure or the determination of the herbicides simazine, propazine, bromacil, metoxuron, and hexazinone is elaborated. Stationary phases RP8 and RP18 and mixtures of methanol-water (2:1 and 1:1, v/v) as a mobile phase are applied for this purpose. The conditions for solid-phase extraction are established, allowing the separation of phenols and herbicides in their mixtures and the extraction of phenols (from river and coke plant water) and herbicides (from the soil samples).  (+info)

Differential modulation of catecholamines by chlorotriazine herbicides in pheochromocytoma (PC12) cells in vitro. (2/14)

Epidemiological, wildlife, and laboratory studies have pointed to the possible adverse health effects of chlorotriazine herbicide (i.e. , atrazine, simazine, and cyanazine) exposure. However, the cellular mechanism(s) of action of these compounds remains unknown. Recently, it was reported by Cooper et al. (2000, Toxicol. Sci. 53, 297-307) that atrazine disrupts ovarian function by altering hypothalamic catecholamine concentrations and subsequently the regulation of luteinizing hormone (LH) and prolactin (PRL) secretion by the pituitary. In this study, we examined the effect of three chlorotriazines on catecholamine metabolism in vitro using PC12 cells. Intracellular norepinephrine (NE) and dopamine (DA) concentrations and spontaneous NE release were measured following treatment with different concentrations of atrazine, simazine (0, 12. 5, 25, 50, 100, and 200 microM) and cyanazine (0, 25, 50, 100, and 400 microM) for 6, 12, 18, 24, and 48 h. Atrazine and simazine significantly decreased intracellular DA concentration in a concentration-dependent manner. Intracellular NE concentration was also significantly decreased by 100 and 200 microM atrazine and 200 microM simazine. Similarly, there was a dose-dependent inhibition of NE release with 100 and 200 microM concentrations of both compounds. Although 100 and 400 microM cyanazine increased intracellular NE concentration, 50, 100, and 400 microM cyanazine significantly increased NE release at 24 and 36 h. In contrast, intracellular DA concentration was decreased by cyanazine, but only at 400 microM. The GABA(A)-receptor agonist, muscimol (0, 0.01, 0.1, and 1.0 microM) had no effect on either the release or on intracellular catecholamine concentrations from 6 through 24 h of treatment. Cell viability was somewhat lower in the groups exposed to 100 and 200 microM atrazine and simazine. However, the reduction in viability was significant only in the highest dose of atrazine used (200 microM) at 24 h. Cyanazine did not have an effect on the viability at any of the doses tested, and the cells were functional, even up to 48 h of exposure. These data indicate that both atrazine and simazine inhibit the cellular synthesis of DA mediated by the tyrosine hydroxylase (TH), and NE mediated by dopamine beta-hydroxylase (DbetaH), and, as a result, there is a partial or significant inhibition of NE release. Cyanazine, on the other hand, stimulated the synthesis of intracellular NE, and not DA. Thus, chlorotriazine compounds presumably act at the enzymatic steps or sites of CA biosynthesis to modulate monoaminergic activity in PC12 cells.  (+info)

Effects of chloro-s-triazine herbicides and metabolites on aromatase activity in various human cell lines and on vitellogenin production in male carp hepatocytes. (3/14)

We investigated a potential mechanism for the estrogenic properties of three chloro-s-triazine herbicides and six metabolites in vitro in several cell systems. We determined effects on human aromatase (CYP19), the enzyme that converts androgens to estrogens, in H295R (adrenocortical carcinoma), JEG-3 (placental choriocarcinoma), and MCF-7 (breast cancer) cells; we determined effects on estrogen receptor-mediated induction of vitellogenin in primary hepatocyte cultures of adult male carp (Cyprinus carpio). In addition to atrazine, simazine, and propazine, two metabolites--atrazine-desethyl and atrazine-desisopropyl--induced aromatase activity in H295R cells concentration-dependently (0.3-30 microM) and with potencies similar to those of the parent triazines. After a 24-hr exposure to 30 microM of the triazines, an apparent maximum induction of about 2- to 2.5-fold was achieved. The induction responses were confirmed by similar increases in CYP19 mRNA levels, determined by reverse-transcriptase polymerase chain reaction. In JEG-3 cells, where basal aromatase expression is about 15-fold greater than in H295R cells, the induction responses were similar but less pronounced; aromatase expression in MCF-7 cells was neither detectable nor inducible under our culture conditions. The fully dealkylated metabolite atrazine-desethyl-desisopropyl and the three hydroxylated metabolites (2-OH-atrazine-desethyl, -desisopropyl, and -desethyl-desisopropyl) did not induce aromatase activity. None of the triazine herbicides nor their metabolites induced vitellogenin production in male carp hepatocytes; nor did they antagonize the induction of vitellogenin by 100 nM (EC(50) 17beta-estradiol. These findings together with other reports indicate that the estrogenic effects associated with the triazine herbicides in vivo are not estrogen receptor-mediated, but may be explained partly by their ability to induce aromatase in vitro.  (+info)

Effects of selected herbicides and plant hormones on Prototheca wickerhamii. (4/14)

Prototheca wickerhamii was treated in vitro with 11 different herbicides and plant hormones. Growth was inhibited by indolyl-3-acetic acid, indolyl-3-butyric acid and indolyl-3-propionic acid at 400 mug per ml. Coconut milk was stimulatory.  (+info)

Atrazine-induced aromatase expression is SF-1 dependent: implications for endocrine disruption in wildlife and reproductive cancers in humans. (5/14)

BACKGROUND: Atrazine is a potent endocrine disruptor that increases aromatase expression in some human cancer cell lines. The mechanism involves the inhibition of phosphodiesterase and subsequent elevation of cAMP. METHODS: We compared steroidogenic factor 1 (SF-1) expression in atrazine responsive and non-responsive cell lines and transfected SF-1 into nonresponsive cell lines to assess SF-1's role in atrazine-induced aromatase. We used a luciferase reporter driven by the SF-1-dependent aromatase promoter (ArPII) to examine activation of this promoter by atrazine and the related simazine. We mutated the SF-1 binding site to confirm the role of SF-1. We also examined effects of 55 other chemicals. Finally, we examined the ability of atrazine and simazine to bind to SF-1 and enhance SF-1 binding to ArPII. RESULTS: Atrazine-responsive adrenal carcinoma cells (H295R) expressed 54 times more SF-1 than nonresponsive ovarian granulosa KGN cells. Exogenous SF-1 conveyed atrazine-responsiveness to otherwise nonresponsive KGN and NIH/3T3 cells. Atrazine induced binding of SF-1 to chromatin and mutation of the SF-1 binding site in ArPII eliminated SF-1 binding and atrazine-responsiveness in H295R cells. Out of 55 chemicals examined, only atrazine, simazine, and benzopyrene induced luciferase via ArPII. Atrazine bound directly to SF-1, showing that atrazine is a ligand for this "orphan" receptor. CONCLUSION: The current findings are consistent with atrazine's endocrine-disrupting effects in fish, amphibians, and reptiles; the induction of mammary and prostate cancer in laboratory rodents; and correlations between atrazine and similar reproductive cancers in humans. This study highlights the importance of atrazine as a risk factor in endocrine disruption in wildlife and reproductive cancers in laboratory rodents and humans.  (+info)

Pesticide levels in ground and surface waters of Primavera do Leste Region, Mato Grosso, Brazil. (6/14)

Residues of the herbicides simazine, metribuzin, metolachlor, trifluralin, atrazine, and two metabolites of atrazine, deisopropylatrazine (DIA) and deethylatrazine (DEA), are surveyed in the surface and groundwater of the Primavera do Leste region, Mato Grosso, Brazil during September and December 1998 and April 1999. Different water source sampling stations of groundwater (irrigation water well, drinking water well, and water hole) and surface water (dam and river) are set up based on agricultural land use. A solid-phase extraction procedure followed by gas chromatography-nitrogen-phosphorus detection is used for the determination of these compounds. All compounds are detected at least once in water samples. A temporal trend of pesticide contamination is observed, with the highest contamination frequency occurring in December during the main application season. Metribuzin shows the highest individual detection frequencies throughout the monitoring period, followed by metolachlor, simazine, and DEA. The maximum mean concentrations of pesticides in this study are in the range from 0.14 to 1.7 microg/L. We deduct that the contamination of water resources is predominantly caused by non-point pollution of pesticides used in intensive cash-crop cultures of the Cerrado area. Therefore, a continuous monitoring of pesticide concentrations in water resources of this tropical region is necessary to detect the longer term contamination trends and developing health risks.  (+info)

Determination of atrazine and simazine in environmental water samples by dispersive liquid-liquid microextraction with high performance liquid chromatography. (7/14)

This paper describes a new method for the rapid and sensitive analysis of atrazine and simazine based on the dispersive liquid-liquid microextraction with carbon tetrachloride and methanol as the extraction solvent and disperser solvent. Under the optimal conditions, there are excellent linear relationships between the peak area and the concentration in the range of 0.5 - 50 microg L(-1) for atrazine and 0.1 - 50 microg L(-1) for simazine. The limits of detection were 0.1 and 0.04 microg L(-1) for atrazine and simazine, respectively. The proposed method was also applied to the analysis of real water samples, and excellent results were achieved with spiked recoveries in the range of 60.7 - 91.4%. All these results demonstrate that the proposed method would be widely used in many fields in the future.  (+info)

Immunochemical screening of pesticides (simazine and cypermethrin) in orange oil. (8/14)

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