The endocrine system is a messenger system in an organism comprising feedback loops of hormones that are released by internal glands directly into the circulatory system and that target and regulate distant organs. In vertebrates, the hypothalamus is the neural control center for all endocrine systems.
Phthalates, or phthalate esters, are esters of phthalic acid. They are mainly used as plasticizers, i.e., substances added to plastics to increase their flexibility, transparency, durability, and longevity. They are used primarily to soften polyvinyl chloride (PVC). Note that while phthalates are usually plasticizers, not all plasticizers are phthalates. The two terms are specific and unique and cannot be used interchangeably.
Hypogonadism means diminished functional activity of the gonads—the testicles or the ovaries—that may result in diminished production of sex hormones. Low androgen levels are referred to as hypoandrogenism and low estrogen as hypoestrogenism. These are responsible for the observed signs and symptoms in both males and females.
Endocrine disruptors, sometimes also referred to as hormonally active agents, endocrine disrupting chemicals, or endocrine disrupting compounds are chemicals that can interfere with endocrine systems. These disruptions can cause numerous adverse human health outcomes including, alterations in sperm quality and fertility, abnormalities in sex organs, endometriosis, early puberty, altered nervous system function, immune function, certain cancers, respiratory problems, metabolic issues, diabetes, obesity, cardiovascular problems, growth, neurological and learning disabilities, and more. Found in many household and industrial products, endocrine disruptors "interfere with the synthesis, secretion, transport, binding, action, or elimination of natural hormones in the body that are responsible for development, behavior, fertility, and maintenance of homeostasis ."
Persistent organic pollutants (POPs) are organic compounds that are resistant to degradation through chemical, biological, and photolytic processes. They are toxic and adversely affect human health and the environment around the world. Because they can be transported by wind and water, most POPs generated in one country can and do affect people and wildlife far from where they are used and released.
Nonylphenols are a family of closely related organic compounds composed of phenol bearing a 9 carbon-tail. Nonylphenols can come in numerous structures, all of which may be considered alkylphenols. They are used in manufacturing antioxidants, lubricating oil additives, laundry and dish detergents, emulsifiers, and solubilizers. They are used extensively in epoxy formulation in North America but its use has been phased out in Europe. These compounds are also precursors to the commercially important non-ionic surfactants alkylphenol ethoxylates and nonylphenol ethoxylates, which are used in detergents, paints, pesticides, personal care products, and plastics. Nonylphenol has attracted attention due to its prevalence in the environment and its potential role as an endocrine disruptor and xenoestrogen, due to its ability to act with estrogen-like activity. The estrogenicity and biodegradation heavily depends on the branching of the nonyl sidechain. Nonylphenol has been found to act as an agonist of the GPER (GPR30).
Xenoestrogens are a type of xenohormone that imitates estrogen. They can be either synthetic or natural chemical compounds. Synthetic xenoestrogens include some widely used industrial compounds, such as PCBs, BPA, and phthalates, which have estrogenic effects on a living organism even though they differ chemically from the estrogenic substances produced internally by the endocrine system of any organism. Natural xenoestrogens include phytoestrogens which are plant-derived xenoestrogens. Because the primary route of exposure to these compounds is by consumption of phytoestrogenic plants, they are sometimes called "dietary estrogens". Mycoestrogens, estrogenic substances from fungi, are another type of xenoestrogen that are also considered mycotoxins.
Vinclozolin is a common dicarboximide fungicide used to control diseases, such as blights, rots and molds in vineyards, and on fruits and vegetables such as raspberries, lettuce, kiwi, snap beans, and onions. It is also used on turf on golf courses. Two common fungi that vinclozolin is used to protect crops against are Botrytis cinerea and Sclerotinia sclerotiorum. First registered in 1981, vinclozolin is widely used but its overall application has declined. As a pesticide, vinclozolin is regulated by the United States Environmental Protection Agency. In addition to these restrictions within the United States, as of 2006 the use of this pesticide was banned in several countries, including Denmark, Finland, Norway, and Sweden. It has gone through a series of tests and regulations in order to evaluate the risks and hazards to the environment and animals. Among the research, a main finding is that vinclozolin has been shown to be an endocrine disruptor with antiandrogenic effects.
A reproductive system disease is any disease of the human reproductive system.
Gonadal dysgenesis is classified as any congenital developmental disorder of the reproductive system in humans. It is atypical development of gonads in an embryo. One type of gonadal dysgenesis is the development of functionless, fibrous tissue, termed streak gonads, instead of reproductive tissue. Streak gonads are a form of aplasia, resulting in hormonal failure that manifests as sexual infantism and infertility, with no initiation of puberty and secondary sex characteristics.
Obesogens are certain chemical compounds that are hypothesised to disrupt normal development and balance of lipid metabolism, which in some cases, can lead to obesity. Obesogens may be functionally defined as chemicals that inappropriately alter lipid homeostasis and fat storage, change metabolic setpoints, disrupt energy balance or modify the regulation of appetite and satiety to promote fat accumulation and obesity.
Bisphenol S (BPS) is an organic compound with the formula (HOC6H4)2SO2. It has two phenol functional groups on either side of a sulfonyl group. It is commonly used in curing fast-drying epoxy resin adhesives. It is classified as a bisphenol, and a close molecular analog of bisphenol A (BPA). BPS differentiates from BPA by possessing a sulfone group (SO2) as the central linker of the molecule instead of a dimethylmethylene group (C 2), which is the case of bisphenol A.
Xenohormones or environmental hormones are compounds produced outside of the human body which exhibit endocrine hormone-like properties. They may be either of natural origin, such as phytoestrogens, which are derived from plants, or of synthetic origin. These compounds can cause endocrine disruption by multiple mechanisms including acting directly on hormone receptors, affecting the levels of natural hormones in the body, and by altering the expression of hormone receptors. The most commonly occurring xenohormones are xenoestrogens, which mimic the effects of estrogen. Other xenohormones include xenoandrogens and xenoprogesterones. Xenohormones are used for a variety of purposes including contraceptive & hormonal therapies, and agriculture. However, exposure to certain xenohormones early in childhood development can lead to a host of developmental issues including infertility, thyroid complications, and early onset of puberty. Exposure to others later in life has been linked to increased risks of testicular, prostate, ovarian, and uterine cancers.
Hypergonadotropic hypogonadism (HH), also known as primary or peripheral/gonadal hypogonadism or primary gonadal failure, is a condition which is characterized by hypogonadism which is due to an impaired response of the gonads to the gonadotropins, follicle-stimulating hormone (FSH) and luteinizing hormone (LH), and in turn a lack of sex steroid production. As compensation and the lack of negative feedback, gonadotropin levels are elevated. Individuals with HH have an intact and functioning hypothalamus and pituitary glands so they are still able to produce FSH and LH. HH may present as either congenital or acquired, but the majority of cases are of the former nature. HH can be treated with hormone replacement therapy.
Testicular dysgenesis syndrome is a male reproduction-related condition characterized by the presence of symptoms and disorders such as hypospadias, cryptorchidism, poor semen quality, and testicular cancer. The concept was first introduced by N.E. Skakkaebaek in a research paper along with the department of Growth and Reproduction in Copenhagen University. The paper suggests the origin and underlying cause of TDS can be detected as early as in fetal life, where environmental and genomic factors could affect the development of the male reproductive system.
Obesity is defined as an abnormal accumulation of body fat, usually 20% or more over an individual's ideal body weight. This is often described as a body mass index (BMI) over 30. However, BMI does not account for whether the excess weight is fat or muscle, and is not a measure of body composition. For most people, however, BMI is an indication used worldwide to estimate nutritional status. Obesity is usually the result of consuming more calories than the body needs and not expending that energy by doing exercise. There are genetic causes and hormonal disorders that cause people to gain significant amounts of weight but this is rare. People in the obese category are much more likely to suffer from fertility problems than people of normal healthy weight.
16α-LE2, or 16α-lactone-estradiol, also known as 3,17β-dihydroxy-19-nor-17α-pregna-1,3,5-(10)-triene-21,16α-lactone, is a synthetic, steroidal estrogen featuring an estradiol core. It is a highly potent and selective agonist of the ERα that is used in scientific research to study the function of the ERα. It has 265-fold higher potency in transactivation assays of the ERα relative to the ERβ and 70-fold preference in binding affinity for the ERα over the ERβ.
8β-VE2, or 8β-vinylestradiol, also known as 8β-vinylestra-1,3,5(10)-triene-3β,17β-diol, is a synthetic estrogen featuring an estradiol core. It is a highly potent and selective agonist of the ERβ that is used in scientific research to study the function of the ERβ. It has 190-fold higher potency in transactivation assays of the ERβ relative to the ERα and 93- (rat) and 180-fold (human) preference in binding affinity for the ERβ over the ERα.
E-SCREEN is a cell proliferation assay based on the enhanced proliferation of human breast cancer cells (MCF-7) in the presence of estrogen active substances. The E-SCREEN test is a tool to easily and rapidly assess estrogenic activity of suspected xenoestrogens. This bioassay measures estrogen-induced increase of the number of human breast cancer cell, which is biologically equivalent to the increase of mitotic activity in tissues of the genital tract. It was originally developed by Soto et al. and was included in the first version of the OECD Conceptual Framework for Testing and Assessment of Endocrine Disrupters published in 2012. However, due to failed validation, it was not included in the updated version of the framework published in 2018.
The CompTox Chemicals Dashboard is a freely accessible online database created and maintained by the U.S. Environmental Protection Agency (EPA). The database provides access to multiple types of data including physicochemical properties, environmental fate and transport, exposure, usage, in vivo toxicity, and in vitro bioassay. EPA and other scientists use the data and models contained within the dashboard to help identify chemicals that require further testing and reduce the use of animals in chemical testing. The Dashboard is also used to provide public access to information from EPA Action Plans, e.g. around perfluorinated alkylated substances.
