- Open Access
Hypothyroidism and brain developmental players
© Ahmed; licensee BioMed Central. 2015
Received: 19 November 2014
Accepted: 23 January 2015
Published: 11 February 2015
Most of our knowledge on the mechanisms of thyroid hormone (TH) dependent brain development is based on clinical observations and animal studies of maternal/fetal hypothyroidism. THs play an essential role in brain development and hormone deficiency during critical phases in fetal life may lead to severe and permanent brain damage. Maternal hypothyroidism is considered the most common cause of fetal TH deficiency, but the problem may also arise in the fetus. In the case of congenital hypothyroidism due to defects in fetal thyroid gland development or hormone synthesis, clinical symptoms at birth are often mild as a result of compensatory maternal TH supply. TH transporters (THTs) and deiodinases (Ds) are important regulators of intracellular triiodothyronine (T3) availability and therefore contribute to the control of thyroid receptors (TRs)-dependent CNS development and early embryonic life. Defects in fetal THTs or Ds may have more impact on fetal brain since they can result in intracellular T3 deficiency despite sufficient maternal TH supply. One clear example is the recent discovery of mutations in the TH transporter (monocarboxylate transporter 8; MCT8) that could be linked to a syndrome of severe and non reversible psychomotor retardation. Even mild and transient changes in maternal TH levels can directly affect and alter the gene expression profile, and thus disturb fetal brain development. Animal studies are needed to increase our understanding of the exact role of THTs and Ds in prenatal brain development.
Thyroid hormone (TH) is essential for a number of physiological processes and is particularly critical during nervous system development [1-7]. In developing brain THs stimulate and coordinate processes such as neuronal proliferation, migration, growth of axons and dendrites, synapse formation and myelination [4,7-22]. Disturbance of these processes leads to abnormalities in the neuronal network and may result in mental retardation and other neurological defects, including impaired motor skills and visual processing [23-27]. Hypothyroidism in adults has been associated with mood symptoms and reduced quality of life [16,28,29]. It is estimated that more than 12% of the US population will develop a thyroid condition during their lifetime, and an estimated 20 million Americans have already some form of thyroid disease . Besides, some of the most prominent and common symptoms of thyroid disease are those that result from the effects of TH on the CNS .
Types of thyroid hormones transporters and their iodothyronine derivates 
T3, T4, rT3, T2
T3, T4, rT3, T2, T4S, T3S, rT3S, T2S
T4, T3, rT3
T4, T3, T3S, T4S, rT3S
rT3, T4S, T3S, rT3S
T4, rT3, T3, T4S
T3, T4, rT3
T3, T4, rT3, T2
T4, T3, T4S, T3S
The importance of THTs for brain development was clearly demonstrated when researchers were able to link mutations in the human SLC16A2 gene coding for MCT8 to a previously described form of X-linked psychomotor retardation, the Allan-Herndon-Dudley syndrome [44,45]. All patients have a severe mental retardation, they cannot speak and most of them are unable to sit upright, crawl, stand or walk. Their thyroid phenotype is quite abnormal with a substantial decrease in plasma T4 and a more than twofold increase in plasma T3 as well as an increase in thyroid-stimulating hormone (TSH). Notably, preterm infants show transient hypothyroxinemia without TSH elevation . In addition, the degree of neurodevelopmental delay in preterm infants becomes severe according to the decreasing gestational age. Epidemiological and animal studies had shown that maternal subclinical hypothyroidism had significant negative impact on neurodevelopment [19,22,47]. To gain further insight in the pathogenic mechanisms underlying these diseases, MCT8 knockout (KO) mice have been generated [42,48]. The serum TH parameters in MCT8 KO mice are affected in the same way as in human patients but surprisingly they seem to develop normally, without overt neurological phenotype. Further analysis showed that the entry of T4 into the brain was not disturbed while uptake of T3 was diminished; suggesting that MCT8 is very important for T3 transport across the BBB and/or BCSFB while the passage of T4 is facilitated by other transporters . The overall T4 and T3 content of cerebrum and cerebellum were decreased by more than 50%, but detailed morphological studies as well as analysis of T3 target genes showed that neuronal uptake of T3 was impaired in an area- or even cell-specific manner. There were signs of a pronounced hypothyroid status in the thyroid-releasing hormone (TRH) producing neurons of the hypothalamic paraventricular nucleus, a mild hypothyroid status in RC3 expressing neurons of the striatum but an apparently normal thyroid status in several cell types in the cerebellum . It was concluded that in mice, more than in humans, other THTs can compensate for the lack of MCT8 in neurons, thereby protecting the brain from severe neurological deficits. The critical restriction to T3 transport in the absence of MCT8 could be located at the BBB rather than the plasma membrane of individual neurons . This agrees with the hypothesis that the high OATP1C1 expression in cerebral microvessels in rodents, as opposed to the situation in humans, contributes to the mild phenotype in MCT8 null mice . Recently also a combined MCT8- and D2-deficient mouse has been described. Analysis of 34 target genes in the cerebral cortex of single and double KO mice demonstrated that the expression of only 3 of them was affected by the elimination of MCT8 alone while this number increased to 24 when both MCT8 and D2 were absent, suggesting that D2 can partly compensate for the decrease in TH uptake in MCT8 deficient mice . While several groups have studied the exact localization of THTs at the level of the BCSFB in the choroid plexus and at the level of the BBB in both macro- and microvessels [51,53], only a few detailed reports are available on their cell-specific distribution in other regions of the brain. In situ hybridization (ISH) for MCT8 in murine brain showed the highest signal in several layers of the cerebral cortex and the hippocampus, in the amygdala, and many basal ganglia. In the cerebellum, expression was predominantly in the Purkinje cell layer. Using specific markers it could be shown that MCT8 is predominantly expressed in neurons, and to some extent in the tanycytes lining the third ventricle [50,54,55]. Analysis of primary murine cell cultures demonstrated high levels of MCT8 protein in neurons and low levels in astrocytes and oligodendrocytes. Importantly, MCT8 deficiency has important metabolic consequences in the brain that could not be correlated with deficiency or excess of TH supply to the brain during adulthood . Also, Müller et al.  indicated that MCT10 indeed participates in tissue-specific TH transport and also contributes to the generation of the unusual serum TH profile characteristic for MCT8 deficiency. LAT1 showed the same expression pattern as MCT8 . MCT8 deficiency has important metabolic consequences in the brain that could not be correlated with deficiency or excess of TH supply to the brain during adulthood . In human late fetal brain LAT2 was found only in microglia while in perinatal mice it was also widely expressed in neurons and astrocytes [35,55]. Information on the ontogenetic changes in THT expression in mammalian brain is quite scarce, especially for early developmental stages. In birds, THTs have been studied first in quail in relation to their possible involvement in the regulation of photoperiodicity at the level of the hypothalamus. Four members of the OATP family were found in choroid plexus: OATP1A1, OATP1B1, OATP1C1, and OATP3A2. The ventro-lateral walls of the basal tuberal hypothalamus showed strong expression of OATP1C1 and weak expression of OATP1B1 . Analysis of chicken OATP1C1 substrate specificity in a cell culture system showed that the protein is a highly specific transporter for T4 (Km 6.8 nM) . While MCT8 mRNA levels increased gradually between embryonic day (E) 4 and E10, OATP1C1 expression showed a divergent pattern. The overviews presented here are consistent with the evolving view that the importance of THTs for proper brain development .
General characteristics of the iodothyronine deiodinases 
Reaction catalyzed (Deiodination)
5 or 5' (ORD+IRD)
T4-T3, rT3- T2
- T4- rT3, T3- T2
- T4- rT3- T2
5: T4S>T3S>>T3, T4
5': rT3, rT3S>T2S>>T4
Sulfation of substrates
Substrate limiting KM
In vitro cofactor limiting KM
1–10 Mm DTT
>10 mM DTT
=70 mM DTT
Molecular mass (kDa)
- Liver, kidney, thyroid and pituitary.
- Pituitary, brain, BAT, thyroida, hearta and skeletal musclea.
- Brain, skin, uterus, placenta, fetus and in other sites of the maternal- fetal interface, such as the umbilical arteries and veins.
- Liver: endoplasmic reticulum. - kidney: basolateral plasma membrane
- Microsomal membranes
- Microsomal membranes
- Production serum T3 and the clearance of serum rT3.
- Catalyzes the outer ring deiodination of T4 to T3 and is thus important for the local production of T3.
- Catalyzes the inner ring deiodination of T4 to rT3 and of T3 to 3,3'-T2.
Activity in hypothyroidism
- Decrease in liver and kidney.
- Increase in all tissues.
- Decrease in brain.
- Increase in thyroid.
- No change
- No change
Active site residues
- Selenocysteine histidine and phenylalanine.
Human gene structure and location
- 1p32-p33, 17.5 kb and 4 exons.
- 14q24.3, 2 exons and 7.4-kb intron.
- TRE, RXR, no CAAT or TATA box.
Iopanoic acid inhibitor
General summary about the developmental thyroid hormone mechanisms (deiodinases, transporters, sulfotransferases and receptors) in human, rat and chicken 
Week post conception
Day post conception
- D3 is detected in uterine wall.
D2 and D3 are observed in uterine wall.
5 h (blastula stage)
- TRα mRNA is noticed and the levels markedly increased during neurulation.
- Thyroid gland begins.
7 -8.5 GD
- Time of implantation process.
- mRNA levels of D1, D2, and D3 are detected in whole embryos.
- Very high D3 activity is detected in decidual tissue.
- TBG is observed in thyroid follicle cells at GD 29.
- Thyroid gland is first visible as an endodermal thickening in the primitive buccal cavity.
- OATP1C1 expression appears.
- TRH is detected in fetal whole-brain at 4.5 weeks of gestation.
- TH is detected in rat embryotrophoblasts
- T4 is transferred via the placenta and has been found in the gestational fluid sac from 4 to 6 W.
- Maternal-embryo transfer of THs has been detected in embryonic coelomic fluid and amniotic fluid.
- All the mRNAs encoding THTs are expressed in placenta from 6 W and throughout pregnancy.
- T4, T3 and rT3 are detected in coelomic/amniotic fluids.
- T4, T3 and TRβ are detected in embryo/trophoblast unit.
- T3, THTs, Ds and TRs are expressed in whole embryos.
- TRs, D2 and D3 are noticed in fetal brain.
- TSH is first detected in the fetal pituitary.
- OATP1C1 expression is more than 10-fold higher in the telencephalon and diencephalon compared to the mesencephalon and rhombencephalon.
- D2 mRNA levels are highest in the diencephalon.
- The fetus is able to produce THs during this period, but prior to that time, is totally dependent on maternal THs.
- TRα mRNA is widely distributed in fore-, mid- and hind-brain.
- TBG levels are detected in fetal serum and increased through gestation.
- T4 and T3 are detected in embryonic brain.
- TRH is detected in fetal hypothalamus.
- D2 activity is observed in the brain before the onset of thyroid function and increases significantly.
- T4 and T3 are observed in serum and brain.
- Placental circulation established.
- D2 mRNA is noticed in cell clusters throughout the brain, particularly in rhombencephalon.
- Total serum T4 and T3 are low, free T4 is relatively high.
- TRs and TH are observed in fetal brain.
- OATP1C1 levels are declined substantially in all brain regions.
- rT3 is noticed in serum relatively high.
- D3 and D2 are detected in uterus and placenta.
- TH synthesis begins in fetal thyroid.
- Decreased mRNA expression of OATP1A2 but no change for OATP4A1 at 9–12 W compared to term.
- Expressions of mRNAs encoding MCT8, MCT10, OATP1A2 and
- TRH mRNA is detected in neurons of the fetal hypothalamus.
- D3 mRNA levels are markedly different in the telencephalon and diencephalon but remain stable, while the levels in mesencephalon and rhombencephalon show a sharp decrease and increase, respectively, during these days.
LAT1 are significantly lower prior to 14 W compared to term
- Pituitary TSH mRNA expression begins.
- Several elements of the TH action cascade are observed in the brain of embryos long before their own thyroid gland starts hormone secretion.
- TRH mRNA is detected in the developing paraventricular nuclei of the hypothalamus.
- D3 is observed in placenta and fetal epithelial cells.
- TRs are observed in liver, heart and lung.
- The thyroid gland is fully functional.
- D3 and TRs are detected in fetal liver.
- D1 and D2 are noticed in fetal tissues.
- D1 is noticed in heart and lung.
- TRH is produced in low levels in hypothalamus and increases approximately threefold by GDI9.5.
- Significant fetal TH secretion begins.
- Duplication of TBG concentrations.
- TH synthesis begins in fetal thyroid
- Brain D2 is elevated at the peak of neuroblast proliferation.
- TSH protein and Sulfotransferase are observed.
18 -22 GD
- The total T4 and T3 concentrations in fetuses are increased dramatically because of maturation of hormone synthesis of the fetal thyroid gland.
- The strong increase in intracellular T3 has been observed.
- The coordination between THTs and Ds is regulated both transplacental TH passage from mother to fetus and the development of the placenta itself through the progress of gestation.
- A steady increase in serum TH levels begins and continues to term.
- Significant fetal TH secretion begins.
- Plasma T4 levels start rising markedly around this day.
- Marked rise in serum TH but levels at birth still below those in adult.
- Serum total and free T4 and T3 near and below adult levels, respectively.
- Birth state.
- The decrease in DI activity in gonads is combined with the relatively high D3 activity.
- Thyroid system is less developed.
- The HPT axis begins to mature during the second half of gestation.
- As much as 17.5% of THs found in the newborn are of maternal origin.
- A significant increase in T3 production and in D2-activity and -mRNA expression are combined with a decreased in D3 activity.
- LAT1 and OATP4A1 have been localized only during the third trimester.
- Birth state.
- Brain development equivalent to human birth.
- Brain D2 activity is moderately elevated, whereas D3 activity and mRNA expression are highest between these days, followed by a dramatic decrease thereafter.
- Complete maturation of thyroid system.
- MCT8 has been localized in the placenta in all three trimesters of pregnancy.
- High concentrations of the different iodothyronine sulfates, T4S, T3S, rT3S and T2S, have been documented in human fetal and neonatal plasma as well as in amniotic fluid during the pregnancy.
- Serum TH levels continue to rise and are higher than adult levels between these days.
- D1 and D3 are expressed in the granule cells, whereas D2 is found mostly in the molecular layer and the Purkinje cells at that time.
- The levels of pituitary and serum TSH slowly decrease from PND 14–16 until reaching adult levels at PND 40.
- The increase in brain T3 production correlates with the appearance of TRβ expression in the cerebellum, telencephalon and optic lobes.
- TRH levels increase to adult levels by PNDI7–29, then decrease transiently between PND 31–41; adult levels are once again reached at PND 50.
E20 (at the moment of pipping)
- The brain is quite well developed at the time of hatching.
- Adult TRH mRNA expression patterns are observed at PND 22.
- The gradual increases in plasma T4 and hepatic D1 are detected.
- D3 levels are decreased in spleen and increased in skin and the lungs towards hatching.
- T3 production seems to be elevated markedly in liver.
- The rise of T4 is much more pronounced than in plasma.
- Diminished T4 sulfation is detected.
Complete maturation of thyroid gland.
- The T3 breakdown capacity by D3 is high in liver but low in kidney.
- T4 levels in plasma increase gradually during these days.
- In contrast to TRα expression which increases gradually towards hatching, expression of TRβ shows an abrupt elevation in late development, especially in the cerebellum.
- The majority of tissues express D3 together with either D1 or D2.
- The levels of D3 activity noticed in liver are rapidly drop by more than 90%.
- D1 levels in testis and ovary strongly decrease around hatching.
- Brain D2 activity is moderately decreased, whereas D3 activity is low.
- The low T3/T4 ratio is associated with high T3 breakdown in liver and with high T4 inactivation or T3 secretion in kidney.
- D1 activity gradually increases, reaching a maximum around these period, and decreases slowly to posthatch levels thereafter.
C1 (first day posthatch)
- The expression of D1 is limited to the mature granule cells and that of D3 to the Purkinje cells exclusively, whereas D2 remains clearly noticed in the molecular layer.
- Highest D1-activities and -mRNA expressions are detected in the liver, kidney, and intestine.
- The circulating T3/T4 ratio started to increase gradually during the first week after hatching.
This work was supported by a National Grant from the Research Center, Beni-Suef University, Beni-Suef city, Egypt.
- Abedelhaffez AS, Hassan A. Brain derived neurotrophic factor and oxidative stress index in pups with developmental hypothyroidism: neuroprotective effects of selenium. Acta Physiol Hung. 2013;100(2):197–210.View ArticlePubMedGoogle Scholar
- Ahmed RG, Incerpi S. Gestational doxorubicin alters fetal thyroid-brain axis. Int J Dev Neurosci. 2013;31:96–104.View ArticlePubMedGoogle Scholar
- Gilbert ME, Ramos RL, McCloskey DP, Goodman JH. Subcortical band heterotopia in rat offspring following maternal hypothyroxinaemia: structural and functional characteristics. J Neuroendocrinol. 2014;26(8):528–41.View ArticlePubMedGoogle Scholar
- Rovet JF. The role of thyroid hormones for brain development and cognitive function. Endocr Dev. 2014;26:26–43.View ArticlePubMedGoogle Scholar
- Sánchez-Huerta K, Pacheco-Rosado J, Gilbert ME. Adult onset-hypothyroidism: alterations in hippocampal field potentials in the dentate gyrus are largely associated with anesthesia-induced hypothermia. J Neuroendocrinol. 2015;27:8–19.View ArticlePubMedGoogle Scholar
- Sawano E, Takahashi M, Negishi T, Tashiro T. Thyroid hormone-dependent development of the GABAergic pre- and post-synaptic components in the rat hippocampus. Int J Dev Neurosci. 2013;31(8):751–61.View ArticlePubMedGoogle Scholar
- Shimokawa N, Yousefi B, Morioka S, Yamaguchi S, Ohsawa A, Hayashi H, et al. Altered cerebellum development and dopamine distribution in a rat genetic model with congenital hypothyroidism. J Neuroendocrinol. 2014;26(3):164–75.View ArticlePubMedGoogle Scholar
- Ahmed OM, Abd El-Tawab SM, Ahmed RG. Effects of experimentally induced maternal hypothyroidism and hyperthyroidism on the development of rat offspring: I- the development of the thyroid hormones-neurotransmitters and adenosinergic system interactions. Int J Dev Neurosci. 2010;28:437–54.View ArticlePubMedGoogle Scholar
- Ahmed OM, Ahmed RG, El-Gareib AW, El-Bakry AM, Abd El-Tawaba SM. Effects of experimentally induced maternal hypothyroidism and hyperthyroidism on the development of rat offspring: II-the developmental pattern of neurons in relation to oxidative stress and antioxidant defense system. Int J Dev Neurosci. 2012;30:517–37.View ArticlePubMedGoogle Scholar
- Ahmed OM, Ahmed RG. Hypothyroidism. In A New Look At Hypothyroidism. Dr. D. Springer (Ed.), ISBN: 978-953-51-0020-1), In Tech Open Access Publisher, Chapter 1, 2012;1–20.Google Scholar
- Ahmed OM, El-Gareib AW, El-bakry AM, Abd El-Tawab SM, Ahmed RG. Thyroid hormones states and brain development interactions. Int J Dev Neurosci. 2008;26(2):147–209. Review.View ArticlePubMedGoogle Scholar
- Ahmed RG, El-Gareib AW, Incerpi S. Lactating PTU exposure: II- Alters thyroid-axis and prooxidant-antioxidant balance in neonatal cerebellum. Int Res J of Natural Sciences. 2014;2(1):1–20.View ArticleGoogle Scholar
- Ahmed RG, El-Gareib AW. Lactating PTU exposure: I- Alters thyroid-neural axis in neonatal cerebellum. Eur J Biol Medical Sci Res. 2014;2(1):1–16.Google Scholar
- Ahmed RG. Does lactating PTU deteriorate thyroid-brain development in newborns? North Carolina, USA: Abstract on the World Congress of Endocrinology- OMICS GROUP (Endocrinology-2013). 2013.Google Scholar
- Ahmed RG. Maternal-fetal thyroid interactions. In: Agrawal NK, editor. In the thyroid hormone, chapter 5. University Campus, STeP Ri Slavka Krautzeka 83/A 51000 Rijeka: Croatia: In tech Open Access Publisher; 2012. p. 125–56.Google Scholar
- Ahmed RG. Maternal–newborn thyroid dysfunction. In: Ahmed RG, editor. In developmental neuroendocrinology. Saarbrücken, Germany: LAP LAMBERT Academic Publishing GmbH & Co KG; 2012. p. 1–369.Google Scholar
- Ahmed RG. Perinatal TCDD exposure alters developmental neuroendocrine system. Food Chemical Toxicol J. 2011;49:1276–84.View ArticleGoogle Scholar
- Ghassabian A, El Marroun H, Peeters RP, Jaddoe VW, Hofman A, Verhulst FC, et al. Downstream effects of maternal hypothyroxinemia in early pregnancy: nonverbal IQ and brain morphology in school-age children. J Clin Endocrinol Metab. 2014;99(7):2383–90.View ArticlePubMedGoogle Scholar
- Koromilas C, Tsakiris S, Kalafatakis K, Zarros A, Stolakis V, Kimpizi D, et al. Experimentally-induced maternal hypothyroidism alters crucial enzyme activities in the frontal cortex and hippocampus of the offspring rat. Metab Brain Dis. 2015;30(1):241–46.View ArticlePubMedGoogle Scholar
- Shiraki A, Saito F, Akane H, Takeyoshi M, Imatanaka N, Itahashi M, et al. Expression alterations of genes on both neuronal and glial development in rats after developmental exposure to 6-propyl-2-thiouracil. Toxicol Lett. 2014;228(3):225–34.View ArticlePubMedGoogle Scholar
- van Mil NH, Steegers-Theunissen RP, Bongers-Schokking JJ, El Marroun H, Ghassabian A, Hofman A, et al. Maternal hypothyroxinemia during pregnancy and growth of the fetal and infant head. Reprod Sci. 2012;19(12):1315–22.View ArticlePubMedGoogle Scholar
- Zhang Y, Fan Y, Yu X, Wang X, Bao S, Li J, Fan C, et al. Maternal subclinical hypothyroidism impairs neurodevelopment in rat offspring by inhibiting the CREB signaling pathway. Mol Neurobiol. 2014 Sep 6 [Epub ahead of print].Google Scholar
- Anderson GW, Schoonover CM, Jones SA. Control of thyroid hormone action in the developing rat brain. Thyroid. 2003;13(11):1039–56.View ArticlePubMedGoogle Scholar
- Gereben B, Zavacki AM, Ribich S, Kim BW, Huang SA, Simonides WS, et al. Cellular and molecular basis of deiodinase-regulated thyroid hormone signaling. Endocr Rev. 2008;29(7):898–938.View ArticlePubMed CentralPubMedGoogle Scholar
- Pop VJ, Brouwers EP, Vader HL, Vulsma T, van Baar AL, de Vijlder JJ. Maternal hypothyroxinaemia during early pregnancy and subsequent child development: a 3-year follow-up study. Clin Endocrinol (Oxf). 2003;59(3):282–8.View ArticleGoogle Scholar
- Van Vliet G, Deladoëy J. Diagnosis, treatment and outcome of congenital hypothyroidism. Endocr Dev. 2014;26:50–9.View ArticlePubMedGoogle Scholar
- Zoeller RT, Rovet J. Timing of thyroid hormone action in the developing brain: clinical observations and experimental findings. J Neuroendocrinol. 2004;16(10):809–18.View ArticlePubMedGoogle Scholar
- Dias GR, de Almeida TM, Sudati JH, Dobrachinski F, Pavin S, Soares FA, et al. Diphenyl diselenide supplemented diet reduces depressive-like behavior in hypothyroid female rats. Physiol Behav. 2014;124:116–22.View ArticlePubMedGoogle Scholar
- Thvilum M, Brandt F, Almind D, Christensen K, Brix TH, Hegedüs L. Increased psychiatric morbidity before and after the diagnosis of hypothyroidism: a nationwide register study. Thyroid. 2014;24(5):802–8.View ArticlePubMedGoogle Scholar
- ATA. Prevalence and impact of thyroid disease. Available: http://www.thyroid.org/. Accessed 2014 September 29.
- Hajje G, Saliba Y, Itani T, Moubarak M, Aftimos G, et al. Hypothyroidism and its rapid correction alter cardiac remodeling. PLoS One. 2014;9(10):e109753.View ArticlePubMed CentralPubMedGoogle Scholar
- Van Herck SLJ, Geysens S, Bald E, Chwatko G, Delezie E, Dianati E, et al. Maternal transfer of methimazole and effects on thyroid hormone availability in embryonic tissues. Endocrinol. 2013;218:105–15.View ArticleGoogle Scholar
- Berbel P, Navarro D, Román GC. An evo-devo approach to thyroid hormones in cerebral and cerebellar cortical development: etiological implications for autism. Frontiers in Endocrinol Thyroid Endocrinol. 2014;5:1–28.Google Scholar
- Bianco AC, Salvatore D, Gereben B, Berry MJ, Larsen PR. Biochemistry, cellular and molecular biology, and physiological roles of the iodothyronine-selenodeiodinases. Endocr Rev. 2002;23:38–89.View ArticlePubMedGoogle Scholar
- Braun D, Kinne A, Bräuer AU, Sapin R, Klein MO, Köhrle J, et al. Developmental and cell type-specific expression of thyroid hormone transporters in the mouse brain and in primary brain cells. Glia. 2011;59(3):463–71.View ArticlePubMedGoogle Scholar
- Bernal J. Thyroid hormone receptors in brain development and function. Nat Clin Pract Endocrinol Metab. 2007;3(3):249–59.View ArticlePubMedGoogle Scholar
- Koibuchi N. The role of thyroid hormone on cerebellar development. Cerebellum. 2008;7:530–3.View ArticlePubMedGoogle Scholar
- Koibuchi N. Animal models to study thyroid hormone action in cerebellum. Cerebellum. 2009;8:89–97.View ArticlePubMedGoogle Scholar
- Koibuchi N, Jingu H, Iwasaki T, Chin WW. Current perspectives on the role of thyroid hormone in growth and development of cerebellum. Cerebellum. 2003;2(4):279–89.View ArticlePubMedGoogle Scholar
- Darras VM, Houbrechts AM, Van Herck SL. Intracellular thyroid hormone metabolism as a local regulator of nuclear thyroid hormone receptor-mediated impact on vertebrate development. Biochim Biophys Acta. 2014;S1874–9399(14):00110–2. doi:10.1016/j.bbagrm.2014.05.004.Google Scholar
- Darras VM, Van Herck SL, Geysens S, Reyns GE. Involvement of thyroid hormones in chicken embryonic brain development. Gen Comp Endocrinol. 2009;163(1–2):58–62.View ArticlePubMedGoogle Scholar
- Trajkovic M, Visser TJ, Mittag J, Horn S, Lukas J, Darras VM, et al. Abnormal thyroid hormone metabolism in mice lacking the monocarboxylate transporter 8. J Clin Invest. 2007;117(3):627–35.View ArticlePubMed CentralPubMedGoogle Scholar
- Van Herck SL, Geysens S, Delbaere J, Darras VM. Regulators of thyroid hormone availability and action in embryonic chicken brain development. Gen Comp Endocrinol. 2013;190:96–104.View ArticlePubMedGoogle Scholar
- Dumitrescu AM, Liao XH, Best TB, Brockmann K, Refetoff S. A novel syndrome combining thyroid and neurological abnormalities is associated with mutations in a monocarboxylate transporter gene. Am J Hum Genet. 2004;74(1):168–75.View ArticlePubMed CentralPubMedGoogle Scholar
- Friesema EC, Grueters A, Biebermann H, Krude H, von Moers A, Reeser M, et al. Association between mutations in a thyroid hormone transporter and severe X-linked psychomotor retardation. Lancet. 2004;364(9443):1435–7.View ArticlePubMedGoogle Scholar
- Nomura S, Ikegami H, Wada H, Tamai H, Funato M, Shintaku H. Role of levothyroxine supplementation in extremely low birth weight infants who have transient hypothyroidism without thyroid-stimulating hormone elevation. Osaka City Med J. 2014;60(1):29–37.PubMedGoogle Scholar
- Özerdem A, Tunca Z, Çımrın D, Hıdıroğlu C, Ergör G. Female vulnerability for thyroid function abnormality in bipolar disorder: role of lithium treatment. Bipolar Disord. 2014;16(1):72–82.View ArticlePubMedGoogle Scholar
- Dumitrescu AM, Liao XH, Weiss RE, Millen K, Refetoff S. Tissue-specific thyroid hormone deprivation and excess in monocarboxylate transporter (mct) 8-deficient mice. Endocrinol. 2006;147(9):4036–43.View ArticleGoogle Scholar
- Heuer H. The importance of thyroid hormone transporters for brain development and function. Best Pract Res Clin Endocrinol Metab. 2007;21(2):265–76.View ArticlePubMedGoogle Scholar
- Ceballos A, Belinchon MM, Sanchez-Mendoza E, Grijota-Martinez C, Dumitrescu AM, Refetoff S, et al. Importance of monocarboxylate transporter 8 for the blood–brain barrier-dependent availability of 3,5,3′-triiodo-L-thyronine. Endocrinology. 2009;150(5):2491–6.View ArticlePubMed CentralPubMedGoogle Scholar
- Roberts LM, Woodford K, Zhou M, Black DS, Haggerty JE, Tate EH, et al. Expression of the thyroid hormone transporters monocarboxylate transporter-8 (SLC16A2) and organic ion transporter-14 (SLCO1C1) at the blood–brain barrier. Endocrinol. 2008;149(12):6251–61.View ArticleGoogle Scholar
- Morte B, Ceballos A, Diez D, Grijota-Martínez C, Dumitrescu AM, Di Cosmo C, et al. Thyroid hormone-regulated mouse cerebral cortex genes are differentially dependent on the source of the hormone: a study in monocarboxylate transporter-8- and deiodinase-2-deficient mice. Endocrinol. 2010;151(5):2381–7.View ArticleGoogle Scholar
- Nagata Y, Kusuhara H, Endou H, Sugiyama Y. Expression and functional characterization of rat organic anion transporter 3 (rOat3) in the choroid plexus. Mol Pharmacol. 2002;61(5):982–8.View ArticlePubMedGoogle Scholar
- Heuer H, Maier MK, Iden S, Mittag J, Friesema EC, Visser TJ, et al. The monocarboxylate transporter 8 linked to human psychomotor retardation is highly expressed in thyroid hormone-sensitive neuron populations. Endocrinol. 2005;146(4):1701–176.View ArticleGoogle Scholar
- Wirth EK, Roth S, Blechschmidt C, Hölter SM, Becker L, Racz I, et al. Neuronal 3′,3,5-triiodothyronine (T3) uptake and behavioral phenotype of mice deficient in Mct8, the neuronal T3 transporter mutated in Allan-Herndon-Dudley syndrome. J Neurosci. 2009;29(30):9439–49.View ArticlePubMedGoogle Scholar
- Rodrigues TB, Ceballos A, Grijota-Martínez C, Nuñez B, Refetoff S, Cerdán S, et al. Increased oxidative metabolism and neurotransmitter cycling in the brain of mice lacking the thyroid hormone transporter Slc16a2 (Mct8). PLoS One. 2013;8(10):e74621. doi:10.1371/journal.pone.0074621.View ArticlePubMed CentralPubMedGoogle Scholar
- Müller J, Mayerl S, Visser TJ, Darras VM, Boelen A, Frappart L, et al. Tissue-specific alterations in thyroid hormone homeostasis in combined Mct10 and Mct8 deficiency. Endocrinol. 2014;155(1):315–25.View ArticleGoogle Scholar
- Nakao N, Takagi T, Iigo M, Tsukamoto T, Yasuo S, Masuda T, et al. Possible involvement of organic anion transporting polypeptide 1c1 in the photoperiodic response of gonads in birds. Endocrinol. 2006;147(3):1067–73.View ArticleGoogle Scholar
- Mayerl S, Müller J, Bauer R, Richert S, Kassmann CM, Darras VM, et al. Transporters MCT8 and OATP1C1 maintain murine brain thyroid hormone homeostasis. J Clin Invest. 2014;124(5):1987–99.View ArticlePubMed CentralPubMedGoogle Scholar
- Heijlen M, Houbrechts AM, Bagci E, Van Herck SL, Kersseboom S, Esguerra CV, et al. Knockdown of type 3 iodothyronine deiodinase severely perturbs both embryonic and early larval development in zebrafish. Endocrinol. 2014;155(4):1547–59.View ArticleGoogle Scholar
- Guadaño-Ferraz A, Obregón MJ, St Germain DL, Bernal J. The type 2 iodothyronine deiodinase is expressed primarily in glial cells in the neonatal rat brain. Proc Natl Acad Sci U S A. 1997;94(19):10391–6.View ArticlePubMed CentralPubMedGoogle Scholar
- Escámez MJ, Guadaño-Ferraz A, Cuadrado A, Bernal J. Type 3 iodothyronine deiodinase is selectively expressed in areas related to sexual differentiation in the newborn rat brain. Endocrinol. 1999;140(11):5443–6.View ArticleGoogle Scholar
- Chan S, Kachilele S, McCabe CJ, Tannahill LA, Boelaert K, Gittoes NJ, et al. Early expression of thyroid hormone deiodinases and receptors in human fetal cerebral cortex. Brain Res Dev Brain Res. 2002;138(2):109–16.View ArticlePubMedGoogle Scholar
- Kester MH, Martínez de Mena R, Obregon MJ, Marinkovic D, Howatson A, Visser TJ, et al. Iodothyronine levels in the human developing brain: major regulatory roles of iodothyronine deiodinases in different areas. J Clin Endocrinol Metab. 2004;89(7):3117–28.View ArticlePubMedGoogle Scholar
- Darras VM, Verhoelst CH, Reyns GE, Kühn ER, Van der Geyten S. Thyroid hormone deiodination in birds. Thyroid. 2006;16(1):25–35.View ArticlePubMedGoogle Scholar
- Van der Geyten S, Van den Eynde I, Segers IB, Kühn ER, Darras VM. Differential expression of iodothyronine deiodinases in chicken tissues during the last week of embryonic development. Gen Comp Endocrinol. 2002;128(1):65–73.View ArticlePubMedGoogle Scholar
- Gereben B, Pachucki J, Kollár A, Liposits Z, Fekete C. Ontogenic redistribution of type 2 deiodinase messenger ribonucleic acid in the brain of chicken. Endocrinol. 2004;145(8):3619–25.View ArticleGoogle Scholar
- Verhoelst CH, Darras VM, Roelens SA, Artykbaeva GM, Van der Geyten S. Type II iodothyronine deiodinase protein in chicken choroid plexus: additional perspectives on T3 supply in the avian brain. Endocrinol. 2004;183(1):235–41.View ArticleGoogle Scholar
- Verhoelst CH, Roelens SA, Darras VM. Role of spatiotemporal expression of iodothyronine deiodinase proteins in cerebellar cell organization. Brain Res Bull. 2005;67(3):196–202.View ArticlePubMedGoogle Scholar
- Verhoelst CH, van der Geyten S, Roelens SA, Darras VM. Regulation of thyroid hormone availability by iodothyronine deiodinases at the blood–brain barrier in birds. Ann N Y Acad Sci. 2005;1040:501–3.View ArticlePubMedGoogle Scholar
- Verhoelst CH, Vandenborne K, Severi T, Bakker O, Zandieh Doulabi B, Leonard JL, et al. Specific detection of type III iodothyronine deiodinase protein in chicken cerebellar purkinje cells. Endocrinol. 2002;143(7):2700–7.View ArticleGoogle Scholar
- Peeters RP, van den Beld AW, Attalki H, Hv T, de Rijke YB, Kuiper GG, et al. A new polymorphism in the type II deiodinase gene is associated with circulating thyroid hormone parameters. Am J Physiol Endocrinol Metab. 2005;289(1):E75–81.View ArticlePubMedGoogle Scholar
- He B, Li J, Wang G, Ju W, Lu Y, Shi Y, et al. Association of genetic polymorphisms in the type II deiodinase gene with bipolar disorder in a subset of Chinese population. Prog Neuropsychopharmacol Biol Psychiatry. 2009;33(6):986–90.View ArticlePubMedGoogle Scholar
- Schneider MJ, Fiering SN, Pallud SE, Parlow AF, St Germain DL, Galton VA. Targeted disruption of the type 2 selenodeiodinase gene (DIO2) results in a phenotype of pituitary resistance to T4. Mol Endocrinol. 2001;15(12):2137–48.View ArticlePubMedGoogle Scholar
- Schneider MJ, Fiering SN, Thai B, Wu SY, St Germain E, Parlow AF, et al. Targeted disruption of the type 1 selenodeiodinase gene (Dio1) results in marked changes in thyroid hormone economy in mice. Endocrinol. 2006;147(1):580–9.View ArticleGoogle Scholar
- Christoffolete MA, Drigo R, Gazoni F, Tente SM, Goncalves V, Amorim BS, et al. Mice with impaired extrathyroidal thyroxine to 3,5,3′-triiodothyronine conversion maintain normal serum 3,5,3′-triiodothyronine concentrations. Endocrinology. 2007;148(3):954–60.View ArticlePubMedGoogle Scholar
- Galton VA, Schneider MJ, Clark AS, St Germain DL. Life without thyroxine to 3,5,3′-triiodothyronine conversion: studies in mice devoid of the 5′-deiodinases. Endocrinol. 2009;150(6):2957–63.View ArticleGoogle Scholar
- Hernandez A, Martinez ME, Fiering S, Galton VA, St Germain D. Type 3 deiodinase is critical for the maturation and function of the thyroid axis. J Clin Invest. 2006;116(2):476–84.View ArticlePubMed CentralPubMedGoogle Scholar
- Geysens S, Ferran J-L, Van Herck SLJ, Tylzanowski P, Puelles L, Darras VM. Dynamic mRNA distribution pattern of thyroid hormone transporters and deiodinases during early embryonic chicken brain development. Neuroscience. 2012;221:69–85.View ArticlePubMedGoogle Scholar
- Galton VA, Wood ET, St Germain EA, Withrow CA, Aldrich G, St Germain GM, et al. Thyroid hormone homeostasis and action in the type 2 deiodinase-deficient rodent brain during development. Endocrinol. 2007;148(7):3080–8.View ArticleGoogle Scholar
- Ng L, Goodyear RJ, Woods CA, Schneider MJ, Diamond E, Richardson GP, et al. Hearing loss and retarded cochlear development in mice lacking type 2 iodothyronine deiodinase. Proc Natl Acad Sci U S A. 2004;101(10):3474–9.View ArticlePubMed CentralPubMedGoogle Scholar
- Hernandez A, Quignodon L, Martinez ME, Flamant F, St Germain DL. Type 3 deiodinase deficiency causes spatial and temporal alterations in brain T3 signaling that are dissociated from serum thyroid hormone levels. Endocrinol. 2010;151(11):5550–8.View ArticleGoogle Scholar
- Ng L, Hernandez A, He W, Ren T, Srinivas M, Ma M, et al. A protective role for type 3 deiodinase, a thyroid hormone-inactivating enzyme, in cochlear development and auditory function. Endocrinol. 2009;150(4):1952–60.View ArticleGoogle Scholar
- Ng L, Lyubarsky A, Nikonov SS, Ma M, Srinivas M, Kefas B, et al. Type 3 deiodinase, a thyroid-hormone-inactivating enzyme, controls survival and maturation of cone photoreceptors. J Neurosci. 2010;30(9):3347–57.View ArticlePubMed CentralPubMedGoogle Scholar
- Fini JB, Le Mével S, Palmier K, Darras VM, Punzon I, Richardson SJ, et al. Thyroid hormone signaling in the Xenopus laevis embryo is functional and susceptible to endocrine disruption. Endocrinol. 2012;153(10):5068–81.View ArticleGoogle Scholar
- Calvo R, Obregón MJ, Ruizde Oña C, Escobardel Rey F, Morrealede Escobar G. Congenital hypothyroidism, as studied in rats. Crucial role of maternal thy Roxine but not of 3,5,3′-triiodothyronine in the protection of the fetal brain. J Clin Invest. 1990;86:889–99.View ArticlePubMed CentralPubMedGoogle Scholar
- Morreale de Escobar G, Ares S, Berbel P, Obregón MJ, Escobardel Rey F. The changing role of maternal thyroid hormone in fetal brain development. Semin Perinatol. 2008;32:380–6.View ArticleGoogle Scholar
- Chan SY, Vasilopoulou E, Kilby MD. The role of the placenta in thyroid hormone delivery to the fetus. Nat Clin Pract Endocrinol Metab. 2009;5:45–54.View ArticlePubMedGoogle Scholar
- Huang CB, Chen FS, Chung MY. Transient hypothyroxinemia of prematurity is associated with abnormal cranial ultrasound and illness severity. Am J Perinatol. 2002;19:139–47.View ArticlePubMedGoogle Scholar
- Glinoer D. The importance of iodine nutrition during pregnancy. Public Health Nutr. 2007;10:1542–6.View ArticlePubMedGoogle Scholar
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.