Endocrine system thyroid

Simon, R., Tietge, J. E., Michalke, B., Degitz, S., Schramm, K. W. Iodine species and the endocrine system thyroid hormone levels in adult Danio rerio and developing Xenopus laevis. Fresenius J Anal Chem 2002, 372, 481 485. 

Octa-BDE and/or congeners present in the commercial mixture have been shown to be neurotoxic and are able to disrupt the endocrine system (thyroid hormone levels) in animals" (p.22)... 

Silva, R. L., De Oliveira, A. F. Neves, E. A. (1998). Spectrophotometric Determination Of lodate In Table Salt. /, Braz. Chem. Soc, Vol.9, No.2, pp 171-174, ISSN 0103-5053 Simon, R., Tietge, J. E., Michalke, B. Degitz, S. Schramm K.-W. (2002). Iodine Species And The Endocrine System Thyroid Hormone Levels In Adult Danio Rerio And Developing Xenopus Laevis. Anal Bioanal Chem, Vol. 372, pp 481-448, ISSN 1618-2642... 

Endocrine system Thyroid dysfunction Sexual disfunction Gynecomastia Addison syndrome Galactorrhea... 

Figure 1 A schematic diagram of the endocrine system of fish. TRH = thyrotrophin releasing hormone GnRH = gonadotrophin releasing hormone CRH = corticotrophin releasing hormone TSH = thyroid stimulating hormone GtH = gonadotrophins I and II ...

Unit IX discusses drugp that affect the endocrine system and consists of five chapters antidiabetic drugs, pituitary and andrenocortical hormones, thyroid and antitliyroid drag s, male and female hormones, and dragp acting on the uterus. 

All OCPs are polytropic, parenchymatous poisons, afflicting the central nervous system, liver, kidneys, the heart muscle, the stomach and intestines, and the endocrine system (mostly the adrenal glands, thyroid, and ovaries). Morphological changes in warm-blooded creatures poisoned by OCPs vary from insignificant disruptions in circulation and reversible dystrophy to focal necroses these effects depend on the organism, the dose of OCP, how long the OCP remains active, as well as on other factors [9, 39, 40, A47, A79]. 

An increase in plethora and focal dystrophic changes in the endocrine system matches clinical observations of changes in adrenal and thyroid function, as well as changes in local and general vascular dystonia, all detected in humans poisoned by OCP. Morphological changes in the brain s nerve cells conform to information on the disruption of reflex activity in the early stages of OCP exposure. 

Li+ has been reported to affect virtually every component of the endocrine system to some extent however any resulting clinical manifestations are very rare [169]. Although these influences do not appear to be related to its mechanism of action in manic-depression, some are involved in the side effects experienced by Li+-treated patients. Apart from elevated levels of thyroid stimulating hormone (TSH), Li+ does not appear to affect the basal levels of hormones significantly however some hormone responses are reported to be altered by Li+ treatment of bipolar patients [170]. Neuronal activity stimulates the adrenal medulla to release norepinephrine and epinephrine into the blood and, consequently, the plasma from people with mania and depression shows increased levels of both neurotransmitters [171]. 

Reports of the effects of Li+ upon the thyroid gland and its associated hormones are the most abundant of those concerned with the endocrine system. Li+ inhibits thyroid hormone release, leading to reduced levels of circulating hormone, in both psychiatric patients and healthy controls [178]. In consequence of this, a negative feedback mechanism increases the production of pituitary TSH. Li+ also causes an increase in hypothalamic thyroid-releasing hormone (TRH), probably by inhibiting its re-... 

In recent years, concern that chemicals might inadvertently be disrupting the endocrine system of humans and wildlife has increased. The concerns regarding exposure to these endocrine disrupters are based on adverse effects observed in certain wildlife, fish, and ecosystems increased incidences of certain endocrine-related human diseases and adverse effects observed in laboratory animals exposed to certain chemicals. The main effects reported in both wildlife and humans concern reproductive and sexual development and function altered immune system, nervous system, and thyroid function and hormone-related cancers. Endocrine dismption is not considered a toxicological endpoint in its own right, but a functional change or toxicological mode(s) of action that may lead to adverse effects. Endocrine dismpters are addressed further in Section 4.11. 

Endocrine diseases and their treatment have a major impact on health throughout the world, particularly in terms of diabetes, thyroid disease, steroid therapy, and control of fertility. Most endocrine therapy is simple and relatively cheap, but a clear understanding of their actions and uses is essential for safe and cost-effective treatment. In this chapter we will focus mainly on well established and validated endocrine therapies that are widely used throughout the world, with briefer mention of drugs that have recently been introduced. In the sections that follow we outline the major issues in the current clinical pharmacology of endocrine disease, covering each of the major endocrine systems in turn. 

Lithium has several effects on the endocrine system. For example, it can interfere with the synthesis and the release of testosterone, leading to an increase in luteinizing hormone levels. The thyroid system has been most implicated in neuroendocrine theories of lithium s antimanic effects. In particular, thyroid hormones can potentiate b-NE activity, and lithium s ability to block their release may subserve its mood-stabilizing properties (i.e., the thyroid-catecholamine receptor hypothesis)... 

Polybrominated Biphenyls. PBBs have the potential to interact with the endocrine system based on effects that mainly include changes in levels of thyroid and female reproductive hormones. No studies were located that investigated the estrogenic and antiestrogenic activity of PBBs in vitro or in vivo at the level of the estrogen receptor. 

The thyroid is a part of the endocrine system. The endocrine system monitors and manufactures or synthesizes many hormones and hormone-like substances. For this reason, the endocrine system and its sub-systems have many built in "checks and balances" to assure proper substance ratio or synergy. It is no surprise that thyroid functions are no exception. 

Thyroid hormone release is subject to the negative feedback strategy that is typical of endocrine systems controlled by the hypothalamic-pituitary axis. Increased circulating levels of the thyroid hormones (T4, T3) serve to limit their own production by inhibiting TRH release from the hypothalamus and TSH release from the anterior pituitary.30,35 This negative feedback control prevents peripheral levels of thyroid hormones from becoming excessively high. 

Endocrine Effects. Little is known about the effects of aluminum on endocrine systems. The oral administration of sodium aluminum phosphate to male and female Beagle dogs for 6 months did not alter thyroid, adrenal, or pituitary gland weight or microanatomy (Katz et al. 1984 Pettersen et al. 1990). These organs were also normal in male and female Wistar rats fed a diet containing unspecified amounts of aluminum phosphide/ammonium carbamate for 24 months (Hackenberg 1972). 

Limited data are available on in vitro effects of barium on the endocrine system. Studies done with isolated pancreatic islet cells from mice show barium is transported across the cell membrane and incorporated into organelles, especially the mitochondria and secretory granules (Berggren et al. 1983). Barium was found to increase cytoplasmic calcium consequently, the insulin- releasing action of barium may be mediated by calcium. Barium has also been found capable of stimulating the calcitonin secretion system of the thyroid in pigs (Pento 1979). 

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