Effects of nonylphenol on the production of progesterone on the rats granulosa cells

Impact of Chemical Endocrine Disruptors and Hormone Modulators on the Endocrine System

There is growing concern regarding the health and safety issues of endocrine-disrupting chemicals (EDCs). Long-term exposure to EDCs has alarming adverse health effects through both hormone-direct and hormone-indirect pathways. Non-chemical agents, including physical agents such as artificial light, radiation, temperature, and stress exposure, are currently poorly investigated, even though they can seriously affect the endocrine system, by modulation of hormonal action. Several mechanisms have been suggested to explain the interference of EDCs with hormonal activity. However, difficulty in quantifying the exposure, low standardization of studies, and the presence of confounding factors do not allow the establishment of a causal relationship between endocrine disorders and exposure to specific toxic agents. In this review, we focus on recent findings on the effects of EDCs and hormone system modulators on the endocrine system, including the thyroid, parathyroid glands, adrenal steroidogenesis, beta-cell function, and male and female reproductive function.

Assessment of the Effective Impact of Bisphenols on Mitochondrial Activity, Viability and Steroidogenesis in a Dose-Dependency in Human Adrenocortical Carcinoma Cells

In recent years, bisphenol analogues such as bisphenol B (BPB), bisphenol F (BPF), and bisphenol S (BPS) have come to replace bisphenol A (BPA) in food packaging and food containers, since BPA has been shown to leach into food and water, causing numerous negative health effects. Although much information on the endocrine activity of BPA is available, a proper human hazard assessment of analogues that are believed to have a less harmful toxicity profile is lacking. The aim of our in vitro study was to assess the potential effect of bisphenol B, F, and S on the biosynthesis of steroid hormones in human H295R adrenocortical carcinoma cells, using the enzyme-linked immunosorbent assay. In addition, we evaluated mitochondrial activity using the MTT test and viability using triple assay. Adrenocortical carcinoma cells were cultivated for 24 h in the presence of bisphenol B, F, or S (0.1, 0.5, 1, 10, 25, 50, 75, 100 μM). We demonstrated that BPB, BPF, and BPS could affect progesterone and testosterone secretion, as well as affect cell mitochondrial, lysosomal, and metabolic activity, as well as plasma membrane integrity, but considerably more detailed and systematic research is required for a better understanding of risks associated with the effects of bisphenols on steroidogenesis.

Effects of nonylphenol induced oxidative stress on apoptosis and autophagy in rat ovarian granulosa cells

Nonylphenol (NP) is a kind of environmental endocrine disruptors which is generally recognized to cause female reproductive toxicity, but its basic mechanism has not been fully elucidated. In this study, granulosa cells (GCs) were treated with 0-70 μM NP for 24 h, the cell viability of GCs was reduced significantly, as well as increased cell apoptosis with G2/M arrest. Furthermore, NP significantly induced autophagy and the production of reactive oxygen species (ROS). However, these phenomenons were inhibited by blocking the production of ROS with N-Acetyl-l-cysteine (NAC) administration. Intriguingly, the inhibition of autophagy with 3-Methyladenine (3-MA) could enhance the apoptosis induced by NP. Moreover, the down regulating of p-Akt/Akt, p-mTOR/mTOR and subsequent up-regulation of p-AMPK/AMPK induced by NP can be rescued by pretreatment of NAC. Our findings suggested that NP promotes rat ovarian GCs apoptosis and autophagy simultaneously, which may involve the activation of ROS-dependent Akt/AMPK/mTOR pathway. Whatever, the activation of autophagy is likely to develop a protective mechanism to improve the apoptosis of rat ovarian GCs induced by NP.

Effect of Montmorillonite on 4-Nonylphenol Enrichment in Zebrafish

The aim of this study was to investigate the effect of montmorillonite on nonylphenol (4-nonylphenol, 4-NP) enrichment in a zebrafish model. The AB strain zebrafish were used as the animal subjects, and three concentration gradients were set for both nonylphenol and montmorillonite, according to their actual concentrations in aquaculture water in Huzhou City. A group treated with nonylphenol alone was also set, adding up to 12 experimental groups. Concentrations of nonylphenol enriched in the liver, muscle and gills of zebrafish were detected by solid phase microextraction–high performance liquid chromatography at Days 7, 15 and 30, respectively. Additionally, the relative enzymatic activity of superoxide dismutase (SOD) and the glutathione S-transferase (GST) were also detected, and the data were statistically analyzed. The results showed that the concentrations of nonylphenol in zebrafish peaked at Day 7 and gradually decreased afterwards for all the experimental groups. The montmorillonite reduces short-term accumulation of nonylphenol in gills, and the high concentration of nonylphenol facilitates its enrichment in liver and muscle, while the low concentration of nonylphenol does not. Meanwhile, the low concentration of nonylphenol in liver exerts an influence on the inductive effect of SOD and GST, while the high concentration of nonylphenol shows the inhibiting effect of SOD and GST.

Disturbing Effects of Chronic Low-dose 4-Nonylphenol exposing on Gonadal Weight and Reproductive Outcome over One-generation

4-Nonylphenol (NP) is a surfactant that is a well-known and widespread estrogenic endocrine disrupting chemical (EDC). Although it has been known that the affinity of NP to ERs is low, it has been suggested that low-dose NP has toxicity. In the present study, the endocrine disrupting effects on reproduction, and the weight of gonads, epididymis, and uterus were evaluated with the chronic lower-dose NP exposing. This study was designed by following the OECD test guideline 443 and subjected to a complete necropsy. In male, NP had an effect on the weight of the testis and epididymis in both F₀ and F₁. In females, NP decreased the weight of ovary and uterus in F₀ but not in pre-pubertal F₁ pubs. Fertility of male and female in F₀ or F₁ was no related with NP administration. The number of caudal-epididymal sperm by body weight (BW) was not different between groups in both F₀ and F₁. Besides, the difference of the sperm number between generations was not detected. The number of ovulated oocytes was similar between groups in F₀, but significantly decreased in NP 50 group of F₁. The litter size and sex ratios of offspring in F₁ and F₂ were not different. The accumulated mating rate and gestation period were not affected by the NP administration. Those results shows that chronic lower-dose NP administration has an effect of endocrine disruptor on the weight of gonads and epididymis of F₀ and F₁ but not in reproduction. Based on the results, it is suggested that chronic lower-dose NP exposing causes endocrine disruption in the weight of gonad and epididymis but not in the reproductive ability of next generations.

Exposure to endocrine disruptors during adulthood: consequences for female fertility

Endocrine disrupting chemicals are ubiquitous chemicals that exhibit endocrine disrupting properties in both humans and animals. Female reproduction is an important process, which is regulated by hormones and is susceptible to the effects of exposure to endocrine disrupting chemicals. Disruptions in female reproductive functions by endocrine disrupting chemicals may result in subfertility, infertility, improper hormone production, estrous and menstrual cycle abnormalities, anovulation, and early reproductive senescence. This review summarizes the effects of a variety of synthetic endocrine disrupting chemicals on fertility during adult life. The chemicals covered in this review are pesticides (organochlorines, organophosphates, carbamates, pyrethroids, and triazines), heavy metals (arsenic, lead, and mercury), diethylstilbesterol, plasticizer alternatives (di-(2-ethylhexyl) phthalate and bisphenol A alternatives), 2,3,7,8-tetrachlorodibenzo-p-dioxin, nonylphenol, polychlorinated biphenyls, triclosan, and parabens. This review focuses on the hypothalamus, pituitary, ovary, and uterus because together they regulate normal female fertility and the onset of reproductive senescence. The literature shows that several endocrine disrupting chemicals have endocrine disrupting abilities in females during adult life, causing fertility abnormalities in both humans and animals.

Risk assessment's insensitive toxicity testing may cause it to fail

BACKGROUND

Risk assessment of chemicals and other agents must be accurate to protect health. We analyse the determinants of a sensitive chronic toxicity study, risk assessment's most important test. Manufacturers originally generate data on the properties of a molecule, and if government approval is needed to market it, laws globally require toxicity data to be generated using Test Guidelines (TG), i.e. test methods of the Organisation for Economic Cooperation and Development (OECD), or their equivalent. TGs have advantages, but they test close-to-poisonous doses for chronic exposures and have other insensitivities, such as not testing disease latency. This and the fact that academic investigators will not be constrained by such artificial methods, created a de facto total ban of academia's diverse and sensitive toxicity tests from most risk assessment.

OBJECTIVE

To start and sustain a dialogue between regulatory agencies and academic scientists (secondarily, industry and NGOs) whose goals would be to (1) agree on the determinants of accurate toxicity tests and (2) implement them (via the OECD).

DISCUSSION

We analyse the quality of the data produced by these incompatible paradigms: regulatory and academic toxicology; analyse the criteria used to designate data quality in risk assessment; and discuss accurate chronic toxicity test methods.

CONCLUSION

There are abundant modern experimental methods (and rigorous epidemiology), and an existing systematic review system, to at long last allow academia's toxicity studies to be used in most risk assessments.

Endocrine disruptors and human corpus luteum: in vitro effects of phenols on luteal cells function

Endocrine disruptors are well known to impair fertility. The aim of the present study was to investigate the effects of bisphenol A (BPA) and nonylphenol (p-NP) on human luteal function in vitro. In particular, in luteal cells isolated from 21 human corpora lutea progesterone, prostaglandin (PG) F2α, PGE2 and vascular endothelial growth factor (VEGF) release, as well as VEGF expression were evaluated. BPA and p-NP negatively affected both luteal steroidogenesis and luteotrophic/ luteolytic factors balance, without influencing VEGF mRNA expression. Actually, BPA and p-NP impaired human luteal cells function in vitro, underlining the already suggested correlation between phenols and reproductive failure.