Inhibition of Type 1 Iodothyronine Deiodinase by Bisphenol A

2019 ◽  
Vol 51 (10) ◽  
pp. 671-677 ◽  
Author(s):  
Maurício Martins da Silva ◽  
Carlos Frederico Lima Gonçalves ◽  
Leandro Miranda-Alves ◽  
Rodrigo Soares Fortunato ◽  
Denise P. Carvalho ◽  
...  

AbstractPlastics are ubiquitously present in our daily life and some components of plastics are endocrine-disrupting chemicals, such as bisphenol A and phthalates. Herein, we aimed to evaluate the effect of plastic endocrine disruptors on type 1 and type 2 deiodinase activities, enzymes responsible for the conversion of the pro-hormone T4 into the biologically active thyroid hormone T3, both in vitro and in vivo. Initially, we incubated rat liver type 1 deiodinase and brown adipose tissue type 2 deiodinase samples with 0.5 mM of the plasticizers, and the deiodinase activity was measured. Among them, only BPA was capable to inhibit both type 1 and type 2 deiodinases. Then, adult male Wistar rats were treated orally with bisphenol A (40 mg/kg b.w.) for 15 days and hepatic type 1 deiodinase and brown adipose tissue type 2 deiodinase activities and serum thyroid hormone concentrations were measured. In vivo bisphenol A treatment significantly reduced hepatic type 1 deiodinase activity but did not affect brown adipose tissue type 2 deiodinase activity. Serum T4 levels were higher in bisphenol A group, while T3 remained unchanged. T3/T4 ratio was decreased in rats treated with bisphenol A, reinforcing the idea that peripheral metabolism of thyroid hormone was affected by bisphenol A exposure. Therefore, our results suggest that bisphenol A can affect the metabolism of thyroid hormone thus disrupting thyroid signaling.

2012 ◽  
Vol 44 (11) ◽  
pp. 797-803 ◽  
Author(s):  
D. Ignacio ◽  
R. Fortunato ◽  
R.A. Neto ◽  
D. da Silva Silvestre ◽  
M. Nigro ◽  
...  

2010 ◽  
Vol 95 (1) ◽  
pp. 256-262 ◽  
Author(s):  
Monica C. Skarulis ◽  
Francesco S. Celi ◽  
Elisabetta Mueller ◽  
Marina Zemskova ◽  
Rana Malek ◽  
...  

Abstract Context: Brown adipose tissue (BAT) found by positron emission/computed tomography (PET-CT) using flouro-deoxyglucose (FDG) is inducible by cold exposure in men. Factors leading to increased BAT are of great interest for its potential role in the treatment of diabetes and obesity. Objective: We tested whether thyroid hormone (TH) levels are related to the volume and activity of BAT in a patient with a mutation in the insulin receptor gene. Design/Setting/Intervention: Our work was based on the case report of a patient in an observational study at the National Institutes of Health. Patient: The patient discontinued insulin and oral antidiabetics after thyroidectomy and suppressive-dose levothyroxine therapy for thyroid cancer. PET-CT uptake in BAT was confirmed by histology and molecular analysis. Outcomes: PET-CT studies were performed, and we measured hemoglobin A1c and resting energy expenditure before and after levothyroxine discontinuation for thyroid cancer testing. Molecular studies of BAT and white adipose samples are presented. Result: Supraclavicular and periumbilical sc adipose tissue demonstrated molecular features of BAT including uncoupling protein-1, type 2 deiodinase, and PR domain containing 16 by quantitative PCR. Activity of type 2 deiodinase activity was increased. The discontinuation of levothyroxine resulted in decreased FDG uptake and diminished volume of BAT depots accompanied by worsening of diabetic control. Conclusions: This case demonstrates the TH effect on BAT activity and volume in this patient and an association between BAT activity and glucose levels in this patient. Because the contribution of TH on skeletal muscle energy expenditure and fuel metabolism was not assessed, an association between BAT activity and glucose homeostasis can only be suggested.


Endocrinology ◽  
2013 ◽  
Vol 154 (1) ◽  
pp. 529-536 ◽  
Author(s):  
Rosalia Lavado-Autric ◽  
Rosa Maria Calvo ◽  
Raquel Martinez de Mena ◽  
Gabriella Morreale de Escobar ◽  
Maria-Jesus Obregon

Severe iodine deficiency is characterized by goiter, preferential synthesis, and secretion of T3 in thyroids, hypothyroxinemia in plasma and tissues, normal or low plasma T3, and slightly increased plasma TSH. We studied changes in deiodinase activities and mRNA in several tissues of rats maintained on low-iodine diets (LIDs) or LIDs supplemented with iodine (LID+I). T4 and T3 concentrations decreased in plasma, tissues, and thyroids of LID rats, and T4 decreased more than T3 (50%). The highest type 1 iodothyronine deiodinase (D1) activities were found in the thyroid, kidney, and the liver; pituitary, lung, and ovary had lower D1 activities; but the lowest levels were found in the heart and skeletal muscle. D1 activity decreased in all tissues of LID rats (10–40% of LID+I rats), except for ovary and thyroids, which D1 activity increased 2.5-fold. Maximal type 2 iodothyronine deiodinase (D2) activities were found in thyroid, brown adipose tissue, and pituitary, increasing 6.5-fold in thyroids of LID rats and about 20-fold in the whole gland. D2 always increased in response to LID, and maximal increases were found in the cerebral cortex (19-fold), thyroid, brown adipose tissue, and pituitary (6-fold). Lower D2 activities were found in the ovary, heart, and adrenal gland, which increased in LID. Type 3 iodothyronine deiodinase activity was undetectable. Thyroidal Dio1 and Dio2 mRNA increased in the LID rats, and Dio1 decreased in the lung, with no changes in mRNA expression in other tissues. Our data indicate that LID induces changes in deiodinase activities, especially in the thyroid, to counteract the low T4 synthesis and secretion, contributing to maintain the local T3 concentrations in the tissues with D2 activity.


2015 ◽  
Vol 54 (03) ◽  
pp. 82-87
Author(s):  
M. Hankir ◽  
K. Krause ◽  
A. Tönjes ◽  
W. K. Fenske ◽  
O. Sabri ◽  
...  

SummaryBrown adipose tissue (BAT) plays an important role in regulating core-body temperature in various species including man. [18F]FDGPET/ CT imaging first revealed the presence of metabolically active BAT depots and that decreased BAT function is associated with various metabolic conditions. Thyroid hormone (TH) in concert with sympathetic nervous system signalling (SNS) stimulates BAT thermogenesis and thyroid disorders result in dysfunctional BAT. Currently, research is focussing not only on BAT regulation but also on browning of white adipose tissue (WAT) to BAT beige adipose tissue (BeAT) in order to develop novel treatments for human obesity and related conditions. While [18F]FDG-PET/ CT imaging is continuing to provide valuable insights into BAT and BeAT function in health and disease, there is a pressing need to develop alternative radiotracers that reliably track their activity in vivo. As a result it is expected that preclinical micro PET/CT investigations of BAT and BeAT will gain in prominence.The aim of this short review is to i) describe fundamentals in BAT biology, ii) highlight some of the clinical and preclinical studies performed on humans and rodents with a focus on TH, BAT and PET/CT, and iii) bridge these data with our own studies within the DFG thyroid transact priority program.


2020 ◽  
Vol 477 (7) ◽  
pp. 1261-1286 ◽  
Author(s):  
Marie Anne Richard ◽  
Hannah Pallubinsky ◽  
Denis P. Blondin

Brown adipose tissue (BAT) has long been described according to its histological features as a multilocular, lipid-containing tissue, light brown in color, that is also responsive to the cold and found especially in hibernating mammals and human infants. Its presence in both hibernators and human infants, combined with its function as a heat-generating organ, raised many questions about its role in humans. Early characterizations of the tissue in humans focused on its progressive atrophy with age and its apparent importance for cold-exposed workers. However, the use of positron emission tomography (PET) with the glucose tracer [18F]fluorodeoxyglucose ([18F]FDG) made it possible to begin characterizing the possible function of BAT in adult humans, and whether it could play a role in the prevention or treatment of obesity and type 2 diabetes (T2D). This review focuses on the in vivo functional characterization of human BAT, the methodological approaches applied to examine these features and addresses critical gaps that remain in moving the field forward. Specifically, we describe the anatomical and biomolecular features of human BAT, the modalities and applications of non-invasive tools such as PET and magnetic resonance imaging coupled with spectroscopy (MRI/MRS) to study BAT morphology and function in vivo, and finally describe the functional characteristics of human BAT that have only been possible through the development and application of such tools.


eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Haiying Zhou ◽  
Bo Wan ◽  
Ivan Grubisic ◽  
Tommy Kaplan ◽  
Robert Tjian

Brown adipose tissue (BAT) plays an essential role in metabolic homeostasis by dissipating energy via thermogenesis through uncoupling protein 1 (UCP1). Previously, we reported that the TATA-binding protein associated factor 7L (TAF7L) is an important regulator of white adipose tissue (WAT) differentiation. In this study, we show that TAF7L also serves as a molecular switch between brown fat and muscle lineages in vivo and in vitro. In adipose tissue, TAF7L-containing TFIID complexes associate with PPARγ to mediate DNA looping between distal enhancers and core promoter elements. Our findings suggest that the presence of the tissue-specific TAF7L subunit in TFIID functions to promote long-range chromatin interactions during BAT lineage specification.


1980 ◽  
Vol 58 (9) ◽  
pp. 1072-1077 ◽  
Author(s):  
Florent Depocas ◽  
Gloria Zaror-Behrens ◽  
Suzanne Lacelle

Desmethylimipramine (DMI, 1 mg DMI∙HCl kg−1) and normetanephrine (NMN, 1 μg min−1 g−0.74) were used to inhibit, respectively, neuronal and extraneuronal uptakes of noradrenaline (NA) during calorigenesis induced in barbital-sedated warm-acclimated (WA) or cold-acclimated (CA) rats by infusion of NA, a procedure which mimics the effects of NA released within calorigenic tissues in response to cold exposure. The doses of the inhibitors were selected for maximal effectiveness in potentiating calorigenic response and for minimal side effects. For rats of either acclimation group treated with DMI and NMN, with DMI only, or with neither inhibitor the doses of NA required to evoke approximately half-maximal calorigenic responses were, respectively, 0.5, 1.0, and 3.5 ng min−1 g−0.74. The corresponding steady-state concentrations of NA in arterial plasma averaged 14.3, 21.7, and 43.2 nM in the three groups of WA rats and 10.0, 14.8, and 31.9 nM in the three groups of CA rats. Reduction by NA uptake inhibitors of the circulating levels of NA necessary to stimulate calorigenesis, half-maximally, presumably in brown adipose tissue, indicates a reduction in the steepness of the NA concentration gradient between capillary plasma and synaptic clefts in that tissue. The steady-state concentration of NA in blood plasma of rats treated with DMI and NMN and infused with NA at a dose of 0.5 ng min−1 g−0.74 (~1 × 10−8 M) is a good estimate of the NA concentration required at calorigenic adrenoceptors to effect half-maximal activation. Presumably, this concentration is also an estimate of that resulting from NA released at nerve endings during cold-induced activation of nonshivering thermogenesis at half-maximal rates in brown adipose tissue.


Sign in / Sign up

Export Citation Format

Share Document