introduction
What are endocrine disruptors?
How can endocrine disruptors enter the human body?
What are the health effects of endocrine disruptors?
Impact on the reproductive system
Effect on the adrenal gland
Effect on the thyroid gland
Effect on the pituitary gland
Endocrine disruptors and endocrine malignant tumors
References
Additional literature
Endocrine disruptors are natural or artificial chemicals that interfere with the body’s endocrine system. The endocrine system includes numerous glands and organs that synthesize, store and secrete hormones. Endocrine disruptors can cause a variety of health conditions, including developmental, reproductive, neurological, and immune disorders.
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What are endocrine disruptors?
More than 1,000 chemicals have been identified in the environment with powerful endocrine disorders. These include pesticides, fungicides, industrial chemicals, plasticizers, nonylphenols, metals, pharmaceutical agents and phytoestrogens.
According to the US Environmental Protection Agency (EPA), any exogenous chemical that can affect the synthesis, transport, metabolism and elimination of endogenous hormones can be defined as an endocrine disruptor.
Based on origin, endocrine disruptors can be categorized as industrial (polychlorinated biphenyls), agricultural (pesticides), pharmaceutical (parabens) and residential (bisphenol A). In addition, heavy metals including lead, mercury, cadmium and arsenic can be considered endocrine disruptors.
How can endocrine disruptors enter the human body?
Endocrine disruptors primarily enter the human body by ingestion (ingestion of food / water), inhalation, or direct exposure of the skin. Most of these chemicals are lipophilic and therefore accumulate in adipose tissue. This results in a very long half-life of these chemicals in the body.
Exposure time is an important parameter in determining the exact effect of endocrine disruptors on humans. In most cases, the effects develop gradually and manifest in later stages of life. In some people, these chemicals do not cause any obvious consequences.
What are the health effects of endocrine disruptors?
Endocrine disruptors can affect the functionality of the endocrine system by altering normal hormone levels, mimicking the functions of endogenous hormones, or altering hormone production.
Endocrine disruptors mimic the functions of endogenous hormones by directly binding and activating a wide range of hormone receptors, including estrogen receptors, androgen receptors, glucocorticoid receptors, thyroid hormone receptors, and the retinoid X receptor.
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Impact on the reproductive system
Since most endocrine disruptors are able to mimic sex hormones, the greatest negative impact has been observed on the reproductive system. by interfering with sex steroid hormones, endocrine disruptors can significantly affect fetal development. Among various disruptors, synthetic estrogens, phytoestrogens, pesticides, plasticizers and industrial chemicals show strong antiandrogenic and weak estrogenic properties.
During ovarian development in animals, endocrine disruptors have been found to interfere with follicle formation, meiosis, and vitality. During the early postnatal period, these chemicals can alter the genetic transcription of somatic cells, which in turn can delay the onset of puberty.
Exposure to endocrine disruptors can cause fertility problems in both men and women. Studies have linked exposure to endocrine disruptors to testicular hypotrophy, polycystic ovaries, testicular dysgenesis syndrome, and hormone-sensitive ovarian and testicular cancer.
Effect on the adrenal gland
High blood flow and large amounts of fatty acids (lipophilic) make the adrenal gland a suitable target for endocrine disruptors. Studies examining the effect of these chemicals on the hypothalamic-pituitary-adrenal axis have highlighted the possibility of impaired synthesis and metabolism of steroid hormones. In particular, endocrine disruptors have been found to interfere with adrenal steroidogenesis by modulating the functions of aromatase, 5-α reductase, and hydroxysteroid dehydrogenase.
Effect on the thyroid gland
Certain endocrine disruptors, including perchlorate and thiocyanate, have been shown to affect iodine absorption by inhibiting the sodium iodide channel. This leads to impaired biosynthesis of thyroid hormones.
Common sources of perchlorate include explosives, airbags, fertilizers and some food items (milk, eggs, fruits and vegetables). Cigarette smoke is a powerful source of thiocyanate. A study involving participants in puberty showed that exposure to perchlorate, thiocyanate and nitrates causes a significant reduction in free thyroxine levels.
Effect on the pituitary gland
Many endocrine disruptors act directly on the diencephalic system, mimicking the functions of neurotransmitters. This later affects the hypothalamic-pituitary-gonadal axis and causes a number of consequences, including delayed onset of puberty and circulatory disorders.
Certain endocrine disruptors, such as estrogen chemicals, have been found to increase the synthesis and secretion of pituitary hormones, including prolactin and thyroid-stimulating hormone (TSH). This subsequently increases the risk of breast and thyroid cancer. In addition, there is evidence to suggest a role for estrogenic chemicals in the development and progression of pituitary cancer.
Endocrine disruptors and endocrine malignant tumors
There is ample evidence that endocrine disruptors increase the risk of testicular, prostate, thyroid and breast cancer. These endocrine disruptors include fungicides, pesticides, polybrominated diphenyl ethers (PDBEs), organochlorides, polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT), dichloro-diphenyl-dichloroethylene (DDE), arsenic and cadmium.
Occupational exposure to pesticides and biocides is associated with a significantly increased risk of thyroid cancer. The risk is more pronounced in men. Similarly, exposure to PCBs, dioxins, cadmium, phytoestrogens, diethylstilbestrol (DES), furans, ethylene oxide has been found to increase the risk of breast cancer. As for prostate cancer, arsenic, cadmium, PCBs and pesticides have been identified as possible contributors.
Endocrine disruptors are everywhere and affect everything: from chemicals that change hormones