Impact of Endocrine Disruptors on the Thyroid Hormone System

Abstract

The thyroid hormone (TH) system plays a central role in central physiological processes of many species, including mammals and humans, ranging from growth and cell differentiation, energy metabolism, thermoregulation and phasing of hibernation or annual movements of migratory species, metamorphosis from larvae to adult forms, brain development, reproduction, or the cardiovascular system. Several chemicals are known to be TH-disrupting compounds (THDCs) and have been shown to interact with virtually all elements of TH homeostasis such as feedback mechanisms with the hypothalamus-pituitary axis, TH synthesis, TH storage and release from the thyroid gland, transport protein binding and TH distribution in tissues and organs, cellular TH uptake, intracellular TH metabolism, and TH receptor binding. Therefore, chemicals interfering with the TH homeostasis have the potential to interact with many of these important processes, and especially early-life stage exposure results in permanent alterations of tissue organization and homeostatic regulation of adaptive processes. This is not only of theoretical importance as the reported plasma concentrations of THDCs in human plasma fall well within the range of reported in vitro effect concentrations, and this is of even higher importance as the developing fetus and young children are in a sensitive developmental stage.

Pesticide toxicogenomics across scales: in vitro transcriptome predicts mechanisms and outcomes of exposure in vivo

“…diet and environmental pollutants, have been involved. Thyroid Disrupting Chemicals (THDCs) exert their effects on function and regulation of the thyroid tissue, especially during the early-life stages67.…”

Maternal Thyroid Hormones: An Unexplored Mechanism Underlying Maternal Effects in an Ecological Framework

“…If such plasma TH variation directly translates to variation in maternal TH levels in eggs, it is likely to be nonadaptive or maladaptive. (5) Thyroid-disrupting chemicals: there is a wide range of chemicals that are known to disrupt the TH homeostasis mainly because of the high degree of structural resemblance to T4 (e.g., reviewed in McNabb 2007;Boas et al 2012;Gutleb et al 2016). They interfere with thyroid function at several levels by interacting with thyroid receptors, binding proteins, and hepatic clearance and subsequently affect circulating TH levels.…”

A hormonális rendszer válsága: az endokrin diszruptorok egészségügyi hatásai

“…Hatásuk érinti a pajzsmirigyhormonok bioszintézi-sét, metabolizmusát és természetesen kötődését, így akcióját is, valamint e hormonok hatása alatt álló szervek (sejtek), így az agy működését [42,43]. Különösen kifejezett a hatásuk a kritikus periódusokban [44]. Polichlorinált bifenilek, dioxinok és furanok hypothyreosist válta-nak ki állatkísérletekben, és a környezetben előforduló dózisban is megbontják a humán pajzsmirigy-homeosztázist [45,46].…”