The regulation of endocrine-disrupting chemicals to minimize their impact on health

Endocrine-disrupting chemicals (EDCs) are substances generated by human industrial activities that are detrimental to human health through their effects on the endocrine system. The global societal and economic burden posed by EDCs is substantial. Poorly defined or unenforced policies can increase human exposure to EDCs, thereby contributing to human disease, disability and economic damage. Researchers have shown that policies and interventions implemented at both individual and government levels have the potential to reduce exposure to EDCs. This Review describes a set of evidence-based policy actions to manage, minimize or even eliminate the widespread use of these chemicals and better protect human health and society. A number of specific challenges exist: defining, identifying and prioritizing EDCs; considering the non-linear or non-monotonic properties of EDCs; accounting for EDC exposure effects that are latent and do not appear until later in life; and updating testing paradigms to reflect 'real-world' mixtures of chemicals and cumulative exposure. A sound strategy also requires partnering with health-care providers to integrate strategies to prevent EDC exposure in clinical care. Critical next steps include addressing EDCs within global policy frameworks by integrating EDC exposure prevention into emerging climate policy.

Assessing utility of thyroid in vitro screening assays through comparisons to observed impacts in vivo

To better understand endocrine disruption, the U.S. Environmental Protection Agency's (USEPA) Endocrine Disruptor Screening Program (EDSP) utilizes a two-tiered approach to investigate the potential of a chemical to interact with the estrogen, androgen, or thyroid systems. As in vivo testing lacks the throughput to address data gaps on endocrine bioactivity for thousands of chemicals, in vitro high-throughput screening (HTS) methods are being developed to screen larger chemical libraries. The primary objective of this work was to investigate for how many of the 52 chemicals with weight-of-evidence (WoE) determinations from EDSP Tier 1 screening there are available in vitro HTS data supporting a thyroid impact. HTS data from the USEPA ToxCast program and the EDSP WoE were collected for this analysis. Considering the complexity of endocrine disruption and interpreting HTS data, concordance between in vitro activity and in vivo effects ranges from 58 to 78%. Based on this evaluation, we conclude that the current suite of HTS assays is beneficial for prioritizing chemicals for further inquiry; however, without a more detailed analysis, one cannot conclude whether HTS results are the primary mode-of-action. Furthermore, development of in vitro assays for additional thyroid-relevant molecular initiating events is required to effectively predict in vivo thyroid impacts.

The genetic background of female reproductive disorders: a systematic review

PURPOSE OF REVIEW

Reproductive function is the interplay between environmental factors and the genetic footprint of each individual. The development in genetic analysis has strengthened its role in the investigation of female reproductive disorders, potential treatment options and provision of personalized care. Despite the increasing requirement of genetic testing, the evidence of the gene-disease relationships (GDR) is limited. We performed a systematic review exploring the associations between the most frequent female reproductive endocrine disorders associated with subfertility [including polycystic ovaries syndrome (PCOS), premature ovarian failure (POI) and hypogonadotropic hypogonadism] and their genetic background in order to summarize current knowledge.

METHODS

A systematic review of relevant literature in accordance with PRISMA guidelines was conducted until July 2022. Data sources that were used are PubMed and Embase.

RECENT FINDINGS

A total of 55 studies were included from the 614 articles identified in the original search. We identified 384 genes associated with one or more of the included female reproductive disorders. The highest number of genes was found to be associated with POI ( N  = 209), followed by hypogonadotropic hypogonadism ( N  = 88) and PCOS ( N  = 87). Four genes, including FSHR , LHβ , LEPR and SF1 were associated with multiple reproductive disorders implying common pathways in the development of those diseases.

SUMMARY

We provide an up-to-date summary of the currently known genes that are associated with three female reproductive disorders (PCOS, POI and hypogonadotropic hypogonadism). The role of genetic analysis in the field of impaired female reproduction may have a role in the diagnosis of female reproductive disorders and personalized patient care.

Long-term effects of COVID-19 on the endocrine system - a pilot case-control study

Background

Coronavirus disease 2019 (COVID-19) has permanently changed the world. Despite having been a pandemic for nearly 3 years, the mid- and long-term complications of this disease, including endocrine disorders, remain unclear. Our study aimed to evaluate the lasting effects of COVID-19 on the endocrine system 6 months after initial infection.

Methods

We compared patients who underwent COVID-19 to age- and sex-matched subjects from a population-based study conducted before the pandemic. We evaluated differences in multiple parameters related to metabolism and the endocrine system including fasting glucose, insulin, lipids, body composition, thyroid stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3), anti-thyroglobulin (aTG) and anti-thyroid peroxidase (aTPO) antibodies, prolactin, cortisol, testosterone, and estradiol.

Results

We found significantly lower levels of fT3 and fT4, accompanied by higher levels of TSH and aTPO antibodies, in COVID-19 survivors. Moreover, we found that patients who underwent SARS-CoV2 infection had higher levels of prolactin and lower levels of testosterone than controls. Interestingly, differences in testosterone levels were observed only in male subjects. We did not detect significant differences in body composition or metabolic and glycemic parameters between cases and controls, except for significantly higher values of the HOMA2-B index in COVID-19 survivors.

Conclusion

Our study indicates that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection might have long-term consequences on the endocrine system, including the suppressed function of the thyroid gland, prolactin, and male sex hormone secretion. Moreover, we showed that in a 6-month follow-up, COVID-19 had no consequences on glycemic parameters, lipid profiles, liver function, body composition, cortisol levels, and estradiol levels.

Acupuncture as multi-targeted therapy for the multifactorial disease obesity: a complex neuro-endocrine-immune interplay

The prevalence of obesity has reached pandemic dimensions. It is associated with multiple comorbidities and is becoming a clinical and public health threat. Obesity is a multifactorial disease with a complex pathophysiology and interplay of various systems. A strong interplay exists between the neuro-endocrine system, the immune system with systemic chronic low-grade inflammation, and microbiome dysbiosis that can lead to the development of obesity, which in turn can exacerbate each of these factors, hence creating a vicious cycle. The conventional treatment with lifestyle modifications such as diet, physical exercise, pharmacotherapy, and bariatric surgery does not always result in sufficient weight control thus paving the way for other strategies. As one such strategy, acupuncture is increasingly used worldwide to treat obesity. This narrative review outlines the evidence for this neuro-endocrine-immune interplay in the pathophysiology of obesity. Furthermore, the existing experimental and clinical evidence of acupuncture as a multi-targeted therapy for obesity is explained and future research perspectives are discussed.

Neurological and endocrinological involvement in neonatal lupus erythematosus: a retrospective study at a tertiary hospital in Eastern China

INTRODUCTION

Neonatal lupus erythematosus (NLE) is a rare autoimmune disease that causes transient impairment of multi-organ functions and is mainly caused by maternally transmitted antibodies.

OBJECTIVE

This study aims to investigate the clinical features of infants with NLE, focusing on the presence of neurological and endocrinological involvement.

METHODS

The clinical data of infants diagnosed with NLE at the Children's Hospital of Soochow University from 2011 to 2022 were collected and retrospectively analyzed.

RESULT

In all, 39 patients with NLE were included, and the most common symptom was rash, followed by hematological, hepatic, cardiac, gastrointestinal, neurological, and endocrine symptoms. Among the 10 patients with neurological impairment, intracranial hemorrhage was the most common, followed by convulsions, hydrocephalus, extracerebral space enlargement, and aseptic meningitis. All patients with neurological impairment were positive for anti-SSA/Ro antibodies. Five of these patients were double positive for anti-SSA/Ro and anti-SSB/La antibodies. All 10 patients had multi-organ system involvement, with hematological involvement being the most common, and three patients had varying degrees of developmental delay at the post-discharge follow-up. Nine patients with endocrine impairment were positive for anti-SSA/Ro antibodies, with pancreatic impairment being the most common. There were four cases of hyperinsulinemia and hypoglycemia, one case of diabetes mellitus with ketoacidosis, two cases of hypothyroidism, one case of hypoadrenocorticism, and one case of lysinuric protein intolerance, all of which were normalized before discharge. All patients with endocrine impairment showed hematological involvement, and some showed feeding intolerance as their first symptom. One patient had abnormal liver function at post-discharge follow-up, and two patients had a rash caused by a severe allergy to milk protein.

CONCLUSIONS

At our hospital, no significant gender differences were observed in the occurrence of NLE, and a predominance of skin, blood, liver, and heart involvement was observed. Patients with multiple central nervous system injuries and organ involvement are more likely to have growth retardation. Endocrine disorders are transient in NLE patients, and some showed feeding intolerance as the first manifestation. Key Points •A retrospective investigation of the clinical characteristics and prognosis of 39 NLE patients was performed, focusing on the clinical features of patients with neurological and endocrine system involvement to improve clinicians' understanding of this disease.

Endocrine immune-related adverse effects of immune-checkpoint inhibitors

INTRODUCTION

Immune-checkpoint inhibitor therapy modulates the response of the immune system acting against cancer. Two pathways impacted by this kind of treatment are the CTLA4 and the PD-1/PD-L1 pathways. ICI therapy can trigger autoimmune adverse effects, known as immune-related Adverse Events (irAEs).

AREAS COVERED

This review focuses on irAEs which affect the endocrine system. This review elucidates the pathways used by these drugs with a focus on the hypothetical pathogenesis at their basis. In fact, the pathophysiology of irAEs concerns the possibility of an interaction between cellular autoimmunity, humoral immunity, cytokines, chemokines, and genetics. The endocrine irAEs examined are thyroid dysfunctions, immune related-hypophysitis, diabetes, peripheral adrenal insufficiency, and hypoparathyroidism.

EXPERT OPINION

There is still much to investigate in endocrine irAES of checkpoint inhibitors. In the future, checkpoint inhibitors will be increasingly utilized therapies, and therefore it is crucial to find the proper diagnostic-therapeutic program for irAEs, especially as endocrine irAEs are nonreversible and require lifelong replacement therapies.

Evaluating H295R steroidogenesis assay data for robust interpretation

The in vitro H295R steroidogenesis assay (OECD TG 456) is used to determine a chemical's potential to interfere with steroid hormone synthesis/metabolism. As positive outcomes in this assay can trigger significant higher tiered testing, we compiled a stakeholder database of reference and test item H295R data to characterize assay outcomes. Information concerning whether a Level 5 reproductive toxicity study was triggered due to a positive outcome in the H295R assay was also included. Quality control acceptance criteria were not always achieved, suggesting this assay is challenging to conduct within the guideline specifications. Analysis of test item data demonstrated that pairwise significance testing to controls allowed for overly sensitive statistically significant positive outcomes, which likely contribute to the assay's high positive hit rate. Complementary interpretation criteria (e.g., 1.5-fold change threshold) markedly reduced the rate of equivocal and positive outcomes thus improving identification of robust positive effects in the assay. Finally, a case study (positive H295R outcome and no endocrine adversity in vivo) is presented, which suggests that stricter data interpretation criteria could refine necessary in vivo follow-up testing. Overall, the described additional criteria could improve H295R data interpretation and help inform on how to best leverage this assay for regulatory purposes.

Aging under endocrine hormone regulation

Aging is a biological process in which the environment interacts with the body to cause a progressive decline in effective physiological function. Aging in the human body can lead to a dysfunction of the vital organ systems, resulting in the onset of age-related diseases, such as neurodegenerative and cardiovascular diseases, which can seriously affect an individual's quality of life. The endocrine system acts on specific targets through hormones and related major functional factors in its pathways, which play biological roles in coordinating cellular interactions, metabolism, growth, and aging. Aging is the result of a combination of many pathological, physiological, and psychological processes, among which the endocrine system can achieve a bidirectional effect on the aging process by regulating the hormone levels in the body. In this paper, we explored the mechanisms of growth hormone, thyroid hormone, and estrogen in the aging process to provide a reference for the exploration of endocrine mechanisms related to aging.

Recent advances in endocrine organoids for therapeutic application

The endocrine system, consisting of the hypothalamus, pituitary, endocrine glands, and hormones, plays a critical role in hormone metabolic interactions. The complexity of the endocrine system is a significant obstacle to understanding and treating endocrine disorders. Notably, advances in endocrine organoid generation allow a deeper understanding of the endocrine system by providing better comprehension of molecular mechanisms of pathogenesis. Here, we highlight recent advances in endocrine organoids for a wide range of therapeutic applications, from cell transplantation therapy to drug toxicity screening, combined with development in stem cell differentiation and gene editing technologies. In particular, we provide insights into the transplantation of endocrine organoids to reverse endocrine dysfunctions and progress in developing strategies for better engraftments. We also discuss the gap between preclinical and clinical research. Finally, we provide future perspectives for research on endocrine organoids for the development of more effective treatments for endocrine disorders.

Pancreatic regional blood flow links the endocrine and exocrine diseases

An increasing number of studies have demonstrated that disease states of the endocrine or exocrine pancreas aggravate one another, which implies bidirectional blood flow between islets and exocrine cells. However, this is inconsistent with the current model of unidirectional blood flow, which is strictly from islets to exocrine tissues. This conventional model was first proposed in 1932, and it has never to our knowledge been revisited to date. Here, large-scale image capture was used to examine the spatial relationship between islets and blood vessels in the following species: human, monkey, pig, rabbit, ferret, and mouse. While some arterioles passed by or traveled through islets, the majority of islets had no association with them. Islets with direct contact with the arteriole were significantly larger in size and fewer in number than those without contact. Unique to the pancreas, capillaries directly branched out from the arterioles and have been labeled as "small arterioles" in past studies. Overall, the arterioles emerged to feed the pancreas regionally, not specifically targeting individual islets. Vascularizing the pancreas in this way may allow an entire downstream region of islets and acinar cells to be simultaneously exposed to changes in the blood levels of glucose, hormones, and other circulating factors.

Endocrine manifestations of COVID-19 in children: A scoping review

In this review, we explore associations between SARS CoV-2 infection and the endocrine system and metabolism in children and adolescents. PubMed, Scopus and Google scholar databases were searched to identify published data on endocrine manifestations of COVID-19 in children up to 31 March 2023, including diabetes, obesity, puberty, thyroid disorders, adrenal disorders and pituitary disorders. Data on changes in disease pattern/ incidence, disease control, and other effects due to the COVID-19 pandemic, as well as effects of pre-existing endocrine conditions on severity of COVID-19 infection are presented, and practice points and research needs provided under each section.

Chlorpropham, a carbamate ester herbicide, has an endocrine-disrupting potential by inhibiting the homodimerization of human androgen receptor

This study was carried out to provide the evidence with respect to the adverse potential of chlorpropham, a representative carbamate ester herbicide product, on the endocrine system by using in vitro testing methods in accordance with the Organization for Economic Cooperation and Development Test Guideline No. 458 (22Rv1/MMTV_GR-KO human androgen receptor [AR] transcriptional activation assay) and a bioluminescence resonance energy transfer-based AR homodimerization assay. Results revealed that chlorpropham had no AR agonistic effects, but it was determined to be a true AR antagonist without intrinsic toxicity against the applied cell lines. In the mechanism of chlorpropham-induced AR-mediated adverse effects, chlorpropham suppressed cytoplasmic AR translocation to the nucleus by inhibiting the homodimerization of the activated ARs. This suggests that chlorpropham exposure caused endocrine-disrupting effects through its interactions with human AR. Additionally, this study might help identify the genomic pathway of the AR-mediated endocrine-disrupting potential of N-phenyl carbamate herbicides.

Endocrine side effects of immune checkpoint inhibitors

Immune checkpoint inhibitors (ICIs) have increasingly been the mainstay of treatment for numerous malignancies. However, due to their association with autoimmunity, ICIs have resulted in a variety of side effects that involve multiple organs including the endocrine system. In this review article, we describe our current understanding of the autoimmune endocrinopathies as a result of the use of ICIs. We will review the epidemiology, pathophysiology, clinical presentation, diagnosis, and management of the most commonly encountered endocrinopathies, including thyroiditis, hypophysitis, Type 1 diabetes, adrenalitis, and central diabetes insipidus.

Cytotoxicity, endocrine disrupting activity, and chemical analysis of 42 food contact silicone rubber products

After migration in 95 % ethanol (food simulant) at 70 °C for 2 h (accelerated conditions), the cytotoxicity and endocrine-disruption activity of 42 food contact silicone products (FCSPs) obtained from the Chinese market were studied. Of 31 kitchenwares, 96 % showed mild or above cytotoxicity (relative growth rate < 80 %) using the HeLa neutral red uptake test; and 84 % showed estrogenic (64 %), anti-estrogenic (19 %), androgenic (42 %), and anti-androgenic (39 %) activities by the Dual-luciferase reporter gene assay. The mold sample induced late phase HeLa apoptosis as detected by Annexin V-FITC/PI double staining flow cytometry, in addition, the migration of mold sample has a higher risk of endocrine disruption at high temperature usage. Encouragingly, 11 bottle nipples had neither cytotoxic nor hormonal activity. Utilizing multiple mass spectrometry techniques, non-intentionally added substances (NIASs) in 31 kitchenwares were analyzed, and the migration levels of 26 organic compounds and 21 metals were quantified, furthermore, the safe risk of single migrant was evaluated through their special migration limit (SML) or threshold of toxicological concern (TTC). Using "nchoosek" statement and Spearman's correlation analysis in MATLAB, the migration of 38 compounds or combinations including metals, plasticizers, methylsiloxanes, and lubricants, had strong correlation with cytotoxicity or hormonal activity. The coexistence of various chemical substances in migrants leads to complex biological toxicity of FCSPs, so it is very important to detect the toxicity of the final products. The combination of bioassays and chemical analyses are valuable tools to facilitate the identification and analyses of FCSPs and migrants that have potential safety risks.

Mercury Bioaccumulation and Cortisol Interact to Influence Endocrine and Immune Biomarkers in a Free-Ranging Marine Mammal

Mercury bioaccumulation from deep-ocean prey and the extreme life history strategies of adult female northern elephant seals (Mirounga angustirostris) provide a unique system to assess the interactive effects of mercury and stress on animal health by quantifying blood biomarkers in relation to mercury (skeletal muscle and blood mercury) and cortisol concentrations. The thyroid hormone thyroxine (tT4) and the antibody immunoglobulin E (IgE) were associated with mercury and cortisol concentrations interactively, where the magnitude and direction of the association of each biomarker with mercury or cortisol changed depending on the concentration of the other factor. For example, when cortisol concentrations were lowest, tT4 was positively related to muscle mercury, whereas tT4 had a negative relationship with muscle mercury in seals that had the highest cortisol concentrations. Additionally, we observed that two thyroid hormones, triiodothyronine (tT3) and reverse triiodothyronine (rT3), were negatively (tT3) and positively (rT3) associated with mercury concentrations and cortisol in an additive manner. As an example, tT3 concentrations in late breeding seals at the median cortisol concentration decreased by 14% across the range of observed muscle mercury concentrations. We also observed that immunoglobulin M (IgM), the pro-inflammatory cytokine IL-6 (IL-6), and a reproductive hormone, estradiol, were negatively related to muscle mercury concentrations but were not related to cortisol. Specifically, estradiol concentrations in late molting seals decreased by 50% across the range of muscle mercury concentrations. These results indicate important physiological effects of mercury on free-ranging apex marine predators and interactions between mercury bioaccumulation and extrinsic stressors. Deleterious effects on animals' abilities to maintain homeostasis (thyroid hormones), fight off pathogens and disease (innate and adaptive immune system), and successfully reproduce (endocrine system) can have significant individual- and population-level consequences.

Endocrine-disrupting chemicals (EDCs) and cancer: new perspectives on an old relationship

PURPOSE

Environmental endocrine-disrupting chemicals (EDCs) are a mixture of chemical compounds capable to interfere with endocrine axis at different levels and to which population is daily exposed. This paper aims to review the relationship between EDCs and breast, prostate, testicle, ovary, and thyroid cancer, discussing carcinogenic activity of known EDCs, while evaluating the impact on public health.

METHODS

A literature review regarding EDCs and cancer was carried out with particular interest on meta-analysis and human studies.

RESULTS

The definition of EDCs has been changed through years, and currently there are no common criteria to test new chemicals to clarify their possible carcinogenic activity. Moreover, it is difficult to assess the full impact of human exposure to EDCs because adverse effects develop latently and manifest at different ages, even if preclinical and clinical evidence suggest that developing fetus and neonates are most vulnerable to endocrine disruption.

CONCLUSION

EDCs represent a major environmental and health issue that has a role in cancer development. There are currently some EDCs that can be considered as carcinogenic, like dioxin and cadmium for breast and thyroid cancer; arsenic, asbestos, and dioxin for prostate cancer; and organochlorines/organohalogens for testicular cancer. New evidence supports the role of other EDCs as possible carcinogenic and pregnant women should avoid risk area and exposure. The relationship between EDCs and cancer supports the need for effective prevention policies increasing public awareness.

New Approach Methodologies for the Endocrine Activity Toolbox: Environmental Assessment for Fish and Amphibians

Multiple in vivo test guidelines focusing on the estrogen, androgen, thyroid, and steroidogenesis pathways have been developed and validated for mammals, amphibians, or fish. However, these tests are resource-intensive and often use a large number of laboratory animals. Developing alternatives for in vivo tests is consistent with the replacement, reduction, and refinement principles for animal welfare considerations, which are supported by increasing mandates to move toward an "animal-free" testing paradigm worldwide. New approach methodologies (NAMs) hold great promise to identify molecular, cellular, and tissue changes that can be used to predict effects reliably and more efficiently at the individual level (and potentially on populations) while reducing the number of animals used in (eco)toxicological testing for endocrine disruption. In a collaborative effort, experts from government, academia, and industry met in 2020 to discuss the current challenges of testing for endocrine activity assessment for fish and amphibians. Continuing this cross-sector initiative, our review focuses on the current state of the science regarding the use of NAMs to identify chemical-induced endocrine effects. The present study highlights the challenges of using NAMs for safety assessment and what work is needed to reduce their uncertainties and increase their acceptance in regulatory processes. We have reviewed the current NAMs available for endocrine activity assessment including in silico, in vitro, and eleutheroembryo models. New approach methodologies can be integrated as part of a weight-of-evidence approach for hazard or risk assessment using the adverse outcome pathway framework. The development and utilization of NAMs not only allows for replacement, reduction, and refinement of animal testing but can also provide robust and fit-for-purpose methods to identify chemicals acting via endocrine mechanisms. Environ Toxicol Chem 2023;42:757-777. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Endocrine responses of the stress system to different types of exercise

Physical activity is an important part of human lifestyle although a large percentage of the population remains sedentary. Exercise represents a stress paradigm in which many regulatory endocrine systems are involved to achieve homeostasis. These endocrine adaptive responses may be either beneficial or harmful in case they exceed a certain threshold. The aim of this review is to examine the adaptive endocrine responses of hypothalamic-pituitary-adrenal axis (HPA), catecholamines, cytokines, growth hormone (GH) and prolactin (PRL) to a single bout or regular exercise of three distinct types of exercise, namely endurance, high-intensity interval (HIIE) and resistance exercise. In summary, a single bout of endurance exercise induces cortisol increase, while regular endurance exercise-induced activation of the HPA axis results to relatively increased basal cortisolemia; single bout or regular exercise induce similar GH peak responses; regular HIIE training lowers basal cortisol concentrations, while catecholamine response is reduced in regular HIIE compared with a single bout of HIIE. HPA axis response to resistance exercise depends on the intensity and volume of the exercise. A single bout of resistance exercise is characterized by mild HPA axis stimulation while regular resistance training in elderly results in attenuated inflammatory response and decreased resting cytokine concentrations. In conclusion, it is important to consider which type of exercise and what threshold is suitable for different target groups of exercising people. This approach intends to suggest types of exercise appropriate for different target groups in health and disease and subsequently to introduce them as medical prescription models.

Exposure to estrone disrupts the endocrine system of western mosquitofish (Gambusia affinis)

Estrone (E1) is one of the predominant natural estrogens detected in aquatic environments, yet little is known about its effects on the endocrine system in fish. In this study, the sex ratio, secondary sexual characteristics, gonadal histology, and transcriptional levels of genes closely related to sex differentiation and hypothalamic-pituitary-gonadal-liver (HPGL) axis were assessed in western mosquitofish (Gambusia affinis) after a full life-cycle exposure to E1 (0, 25.4, 143, 740, and 4300 ng/L) for 119 days. The results showed that exposure to 4300 ng/L of E1 resulted in 100% female and inhibited the growth of females. Exposure to environmentally relevant concentrations of E1 (143 and 740 ng/L) led to obvious feminization of skeletons and anal fins in males. Exposure to 740 and 4300 ng/L of E1 increased the proportion of mature spermatocytes in females, and exposure to 143 and 740 ng/L decreased the proportion of mature spermatocytes in males. Moreover, the transcripts of genes related to sex differentiation and HPGL axis were changed in the E1-exposed adult fish and embryos inside females. This study has provided valuable data on the endocrine disruption effects of E1 at environmentally relevant concentrations in G. affinis.

A comparative study on endocrine disrupting effects of leachates from virgin and aged plastics under simulated media in marine medaka larvae (Oryzias melastigma)

Marine plastic pollution has garnered substantial attention, but the potential endocrine disrupting effects of plastic leachates in marine organisms remain unclear. In this study, the larvae of marine medaka (Oryzias melastigma) were exposed to the leachates from virgin and aged plastics soaked in simulated seawater and fish digest for 3 days. The concentrations of vitellogenin (VTG), estradiol (E2), and 11-ketotestosterone (11-KT), as well as the transcripts of endocrine-related genes were measured in the larvae. The results revealed that endogenous E2 was more sensitive to plastic leachates than VTG and 11-KT, which was significantly affected by 26.7 % of all plastic leachates. Among all genes, estrogen receptor α was impacted mostly, being up-regulated by 53.3 % of leachates from aged plastics. The comparative results demonstrated that the leachates from plastics with different statuses caused a greater difference than those from plastics in different simulated media, and the leachates from aged plastics resulted in higher endocrine disrupting effects than those from virgin plastics. In addition, seven leached additives (plasticizers and flame retardants) could explain 25.6 % of the hormonal effects using redundancy analysis, indicating that other additives in the plastic leachates can also play important roles in regulating the endocrine system of O. melastigma larvae.