There is considerable concern about the substances present in the environment and their potential to interfere with the endocrine system of vertebrates. Among these, the so-called ...endocrine-disrupting compounds, which can modulate or disrupt developmental and reproductive processes, substances with estrogenic activity have attracted most attention. Concerns about the presence of these compounds in the environment have led to the development of screening and testing assays that are able to detect such substances and evaluate their potential to induce adverse effects. In vitro systems such as mammalian and fish cell lines have become of growing importance in toxicity testing of such compounds. The cytotoxic and apoptotic effects induced by 17α-ethynylestradiol and diethylstilbestrol were studied on CHO-K1 cell line. Trypan blue exclusion method was used to determine the cell viability. Cytotoxicity of 17α-ethynylestradiol (0.34-34 µM) and diethylstilbestrol (0.37-37 µM) was found to be concentration-dependent with IC.sub.50 values of 12.8 and 10.4 µM after 72 h of exposure, respectively. In treated CHO-K1 culture cell death was assessed by determining morphological changes by haematoxilyn and eosin staining, nuclear morphology by fluorescein diacetate/propidium iodide staining and fluorescence microscopy, DNA fragmentation by TUNEL method and translocation of phosphatidyl serine by flow cytometry. The obtained results showed that 17α-ethynylestradiol induced apoptosis, while diethylstilbestrol induced necrosis in the treated CHO-K1 cells. Key words: apoptosis, CHO-K1 cells, cytotoxicity, diethylstilbestrol, 17α-ethynylestradiol, necrosis
Atrazine is the most commonly detected pesticide contaminant of ground water, surface water, and precipitation. Atrazine is also an endocrine disruptor that, among other effects, alters male ...reproductive tissues when animals are exposed during development. Here, we apply the nine so-called “Hill criteria” (Strength, Consistency, Specificity, Temporality, Biological Gradient, Plausibility, Coherence, Experiment, and Analogy) for establishing cause–effect relationships to examine the evidence for atrazine as an endocrine disruptor that demasculinizes and feminizes the gonads of male vertebrates. We present experimental evidence that the effects of atrazine on male development are consistent across all vertebrate classes examined and we present a state of the art summary of the mechanisms by which atrazine acts as an endocrine disruptor to produce these effects.
Atrazine demasculinizes male gonads producing testicular lesions associated with reduced germ cell numbers in teleost fish, amphibians, reptiles, and mammals, and induces partial and/or complete feminization in fish, amphibians, and reptiles. These effects are strong (statistically significant), consistent across vertebrate classes, and specific. Reductions in androgen levels and the induction of estrogen synthesis – demonstrated in fish, amphibians, reptiles, and mammals – represent plausible and coherent mechanisms that explain these effects. Biological gradients are observed in several of the cited studies, although threshold doses and patterns vary among species. Given that the effects on the male gonads described in all of these experimental studies occurred only after atrazine exposure, temporality is also met here. Thus the case for atrazine as an endocrine disruptor that demasculinizes and feminizes male vertebrates meets all nine of the “Hill criteria”.
Stolni pozivač konobara je praktičan dodatak stolovima u boljim restoranima s ciljem obavještavanja konobara o svojoj želji, a bez mnogo gestikuliranja i skretanja pozornosti od društva s kojim se ...nalazite u restoranu.Obzirom da nema elektronike, ne kvari se i nema ograničenja upotrebe. Po svojoj namjeni nema ograničenja za bilo koje jezično područje u svijetu.
The effects of subacute exposure to atrazine on body weight, ovarian cycling, conception rate and the size of litters in Fischer strain rats were studied. An atrazine dose of 120 mg kg-1 body wt ...given p.o. daily for 7 days to both female and male rats caused statistically significant loss of body weight in both sexes during the period of treatment. After the cessation of treatment the body weight of female rats remained below control body weights at least for 2 weeks. In male rats the difference in body weights narrowed with time and reached control level 5 days after the last dose. Atrazine caused a significant increase in the relative weights of pituitary and prostate. Atrazine also transiently prolonged the oestrous cycle, characterized by extended vaginal dioestrus. As a result of disturbed ovarian cycling, the rate of successful mating decreased in the first week after treatment when both sexes were exposed or exposed females were mated with an unexposed male. No similar effect was observed when only the males were exposed. The size of litters did not differ significantly between experimental groups.
In this study the effects of ammonium and lactate on a culture of channel catfish ovary (CCO) cells were examined. We also made investigation on the influence of glutamine, since our previous ...research revealed that this amino acid stimulated CCO cell growth more than glucose in a concentration-dependent manner. The effect of ammonium in cell culture included the considerable decrease in cell growth rate with eventual growth arrest as well as the retardation of glucose consumption. At ammonium concentrations above 2.5 mM, the cells displayed specific morphological changes. The effect of lactate was different to that of ammonium since the cell growth rate was progressively decreasing with the increase of lactate concentration, whereas the glucose consumption rate remained almost unchanged. Besides that, it was found that lactate was steadily eliminated from the culture medium when its initial concentration was relatively high. The influence of glutamine on CCO cell propagation showed that nutrient requirements of this cell line were mainly dependent on glutamine rather than glucose. The increase in glutamine concentration led to the increase in cell growth rate and consequent ammonia accumulation while the glucose utilization and lactate production were reduced. Without glutamine in culture medium cell growth was arrested. However, the lack of glucose reversed the stimulating effect of glutamine by decreasing cell growth rate and affecting amino acid utilization.
There is considerable concern about the substances present in the environment and their potential to interfere with the endocrine system of vertebrates. Among these, the so-called ...endocrine-disrupting compounds, which can modulate or disrupt developmental and reproductive processes, substances with estrogenic activity have attracted most attention. Concerns about the presence of these compounds in the environment have led to the development of screening and testing assays that are able to detect such substances and evaluate their potential to induce adverse effects. In vitro systems such as mammalian and fish cell lines have become of growing importance in toxicity testing of such compounds. The cytotoxic and apoptotic effects induced by 17α-ethynylestradiol and diethylstilbestrol were studied on CHO-K1 cell line. Trypan blue exclusion method was used to determine the cell viability. Cytotoxicity of 17α-ethynylestradiol (0.34-34 µM) and diethylstilbestrol (0.37-37 µM) was found to be concentration-dependent with IC^sub 50^ values of 12.8 and 10.4 µM after 72 h of exposure, respectively. In treated CHO-K1 culture cell death was assessed by determining morphological changes by haematoxilyn and eosin staining, nuclear morphology by fluorescein diacetate/propidium iodide staining and fluorescence microscopy, DNA fragmentation by TUNEL method and translocation of phosphatidyl serine by flow cytometry. The obtained results showed that 17α-ethynylestradiol induced apoptosis, while diethylstilbestrol induced necrosis in the treated CHO-K1 cells. PUBLICATION ABSTRACT
The effects of synthetic estrogens 17
α
-ethynylestradiol (EE2) and diethylstilbestrol (DES) were compared on cell proliferation and morphology in Channel Catfish Ovary (CCO) and Chinese Hamster ...Ovary (CHO-K1) cells. EE2 exposure (0.1 and 0.5 μg/mL) induced stimulatory effect on CCO and CHO-K1 cell proliferation, while higher concentrations (1–10 μg/mL) showed cytotoxic effects. Increase in DES concentrations mainly resulted in dose-depended increase in cytotoxicity in both cell lines. Morphological changes induced by EE2 and DES exposure (5 μg/mL) showed disrupted cell monolayer and increased number and size of lysosomes. Comparison of IC
50
values showed almost equal sensitivity towards cytotoxicity of tested compounds in CCO and CHO-K1 cells.
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