scholarly journals The Nutritional Supply of Iodine and Selenium Affects Thyroid Hormone Axis Related Endpoints in Mice

Nutrients ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 3773
Author(s):  
Kristina Lossow ◽  
Kostja Renko ◽  
Maria Schwarz ◽  
Lutz Schomburg ◽  
Tanja Schwerdtle ◽  
...  

Selenium and iodine are the two central trace elements for the homeostasis of thyroid hormones but additional trace elements such as iron, zinc, and copper are also involved. To compare the primary effects of inadequate intake of selenium and iodine on the thyroid gland, as well as the target organs of thyroid hormones such as liver and kidney, mice were subjected to an eight-week dietary intervention with low versus adequate selenium and iodine supply. Analysis of trace element levels in serum, liver, and kidney demonstrated a successful intervention. Markers of the selenium status were unaffected by the iodine supply. The thyroid gland was able to maintain serum thyroxine levels even under selenium-deficient conditions, despite reduced selenoprotein expression in liver and kidney, including deiodinase type 1. Thyroid hormone target genes responded to the altered selenium and iodine supply, whereas the iron, zinc, and copper homeostasis remained unaffected. There was a notable interaction between thyroid hormones and copper, which requires further clarification. Overall, the effects of an altered selenium and iodine supply were pronounced in thyroid hormone target tissues, but not in the thyroid gland.

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Fabrice Chatonnet ◽  
Frédéric Picou ◽  
Teddy Fauquier ◽  
Frédéric Flamant

Thyroid hormones (TH, including the prohormone thyroxine (T4) and its active deiodinated derivative 3,,5-triiodo-L-thyronine (T3)) are important regulators of vertebrates neurodevelopment. Specific transporters and deiodinases are required to ensure T3 access to the developing brain. T3 activates a number of differentiation processes in neuronal and glial cell types by binding to nuclear receptors, acting directly on transcription. Only few T3 target genes are currently known. Deeper investigations are urgently needed, considering that some chemicals present in food are believed to interfere with T3 signaling with putative neurotoxic consequences.


PEDIATRICS ◽  
1966 ◽  
Vol 38 (4) ◽  
pp. 647-651
Author(s):  
Wellington Hung ◽  
Judson G. Randolph ◽  
Domenic Sabatini ◽  
Theodore Winship

Five clinically euthyroid children with lingual or sublingual thyroid glands were seen during a 12-month period. Certain recommendations have been formulated based upon our experience with these patients. A careful physical examination should be performed to demonstrate the presence of a normally located thyroid gland in all children presenting with midline masses in the lingual or sublingual areas. When the thyroid gland cannot be palpated with certainty in these children, a scintiscan with I-131 should be carried out to determine if the mass is an ectopic thyroid gland and if a normally located thyroid gland is present. All children with lingual on sublingual thyroid glands should have a trial of full replacement thyroid hormone therapy before excision is contemplated. Thyroid therapy will prevent further hypertrophy and hyperplasia. Surgical intervention should be reserved for those children in whom there is dysphagia, dysphonia, ulceration, or hemorrhage due to a lingual thyroid gland or if the ectopic thyroid gland fails to decrease in size following a course of treatment with thyroid hormones.


Iodine (I2) is essential in the synthesis of thyroid hormones T4 and T3 and functioning of the thyroid gland. Both T3 and T4 are metabolically active, but T3 is four times more potent than T4. Our body contains 20-30 mg of I2, which is mainly stored in the thyroid gland. Iodine is naturally present in some foods, added to others, and available as a dietary supplement. Serum thyroid stimulating hormone (TSH) level is a sensitive marker of thyroid function. Serum TSH is increased in hypothyroidism as in Hashimoto's thyroiditis. In addition to regulation of thyroid function, TSH promotes thyroid growth. If thyroid hormone synthesis is chronically impaired, TSH stimulation eventually may lead to the development of a goiter. This chapter explores the iodide metabolism and effects of Hashimoto's disease.


2018 ◽  
Vol 238 (1) ◽  
pp. R13-R29 ◽  
Author(s):  
Maik Pietzner ◽  
Tim Kacprowski ◽  
Nele Friedrich

OMICs subsume different physiological layers including the genome, transcriptome, proteome and metabolome. Recent advances in analytical techniques allow for the exhaustive determination of biomolecules in all OMICs levels from less invasive human specimens such as blood and urine. Investigating OMICs in deeply characterized population-based or experimental studies has led to seminal improvement of our understanding of genetic determinants of thyroid function, identified putative thyroid hormone target genes and thyroid hormone-induced shifts in the plasma protein and metabolite content. Consequently, plasma biomolecules have been suggested as surrogates of tissue-specific action of thyroid hormones. This review provides a brief introduction to OMICs in thyroid research with a particular focus on metabolomics studies in humans elucidating the important role of thyroid hormones for whole body metabolism in adults.


1997 ◽  
Vol 9 (5) ◽  
pp. 489 ◽  
Author(s):  
Conrad Sernia ◽  
Tang Zeng ◽  
Robert T. Gemmell

Newborn marsupials do not have a thyroid gland at birth. The gland develops while the young marsupial is in the mother’s pouch. The young brushtail possum initiates secretion of thyroid hormones from its own thyroid at about Day 65 post partum. However, during the first three weeks of pouch life thyroxine is passed from the mother to the young via the milk. To determine if this maternal thyroxine can effect organ development in the young possum before it initiates secretion of thyroxine from its own thyroid, the ontogeny of thyroid hormone receptors was determined in nuclear extracts of lung, liver and kidney by radioreceptor assay, using125I-labelled tri-iodothyronine as ligand. Receptor density was calculated for tissues removed from young possums at Days 25 (n = 5), 50 (n = 4), 100 (n = 3) and 150 (n = 4) and from adults (n = 5). Receptors were found in possums of all age groups, including the small 25-day pouch young. Significant differences were not found in the receptor density between different tissues or at various ages. The association constant Ka (4 ·0 ± 2· 6 L nmol-1 for lung) was similar in different tissues and at the various ages examined. The passage of thyroid hormones from the mother to the developing marsupial via the milk may have a role in the slow development of organ systems early in pouch life by acting on thyroid receptors in the pouch young. However, the functional maturation of the thyroid gland of the young possum, not an increase in receptors, appears to coincide with the rapid increase in the rate of growth and development which occurs in later pouch life.


2011 ◽  
Vol 210 (1) ◽  
pp. 3-4 ◽  
Author(s):  
Marian Ludgate

A paper published in this issue of the Journal of Endocrinology has revisited the hypothesis that thyroid hormones may be generated by tissues outside the thyroid gland in higher organisms including mammals. This commentary appraises the strengths and weaknesses of the study, the alternative explanations for the findings and possible future measures to investigate further. The concept of extrathyroidal thyroxine and triiodothyronine synthesis has previously been proposed; by assuming that Nagao et al. and earlier authors are correct, the plausibility and possible mechanisms underlying the hypothesis are discussed.


Author(s):  
Ferruccio Santini ◽  
Aldo Pinchera

Hypothyroidism is the clinical state that develops as a result of the lack of action of thyroid hormones on target tissues (1). Hypothyroidism is usually due to impaired hormone secretion by the thyroid, resulting in reduced concentrations of serum thyroxine (T4) and triiodothyronine (T3). The term primary hypothyroidism is applied to define the thyroid failure deriving from inherited or acquired causes that act directly on the thyroid gland by reducing the amount of functioning thyroid tissue or by inhibiting thyroid hormone production. The term central hypothyroidism is used when pituitary or hypothalamic abnormalities result in an insufficient stimulation of an otherwise normal thyroid gland. Both primary and central hypothyroidism may be transient, depending on the nature and the extent of the causal agent. Hypothyroidism following a minor loss of thyroid tissue can be recovered by compensatory hyperplasia of the residual gland. Similarly, hypothyroidism subsides when an exogenous inhibitor of thyroid function is removed. Peripheral hypothyroidism may also arise as a consequence of tissue resistance to thyroid hormones due to a mutation in the thyroid hormone receptor. Resistance to thyroid hormones is a heterogeneous clinical entity with most patients appearing to be clinically euthyroid while some of them have symptoms of thyrotoxicosis and others display selected signs of hypothyroidism. The common feature is represented by pituitary resistance to thyroid hormones, leading to increased secretion of thyrotropin that in turn stimulates thyroid growth and function. The variability in clinical manifestations depends on the severity of the hormonal resistance, the relative degree of tissue hyposensitivity, and the coexistence of associated genetic defects (see Chapter 3.4.8).


1996 ◽  
Vol 42 (1) ◽  
pp. 179-182 ◽  
Author(s):  
E C Ridgway

Abstract Primary thyroid gland failure is a common medical disorder occurring in mild or severe forms in 10% to 15% of our population. Symptoms may be classical and easy to recognize or very subtle, escaping clinical detection. This disorder is more common in females and increases with advancing age. The most important diagnostic test is measurement of the serum thyrotropin (TSH) concentration, which will increase above the normal range in both mild and severe cases. Most clinical effects of thyroid hormone deficiency can be explained by the "nuclear thyroid hormone hypothesis," which states that thyroid hormones act predominantly by effecting the transcription of key genes in affected tissues. Therapy of hypothyroidism is easy, inexpensive, and precise, involving pure L-thyroxine and measuring dose requirements and efficacy by monitoring serum TSH concentrations.


1978 ◽  
Vol 26 (12) ◽  
pp. 1121-1124 ◽  
Author(s):  
M Wilson ◽  
K R Hitchcock ◽  
R A DeLellis

Direct and indirect immunofluorescence techniques were used to localize the thyroid hormones triidothyronine (T3) and thyroxine (T4) in adult rat thyroid gland. Optimum dilutions of the antisera were established and four tissue fixatives were investigated for usefulness in this technique. Use of antibodies specific for either T3 or T4 resulted in brilliant fluorescence in the colloid pools and apical cytoplasm of follicular cells. In all cases, the adjacent parathyroid gland was devoid of fluorescence. This report demonstrates that these dipeptide hormones can be localized by using immunofluorescence techniques.


2019 ◽  
Vol 63 (2) ◽  
pp. 267-273
Author(s):  
Joanna Pajdak-Czaus ◽  
Elżbieta Terech-Majewska ◽  
Dagmara Będzłowicz ◽  
Martyn Mączyński ◽  
Wioletta Krystkiewicz ◽  
...  

AbstractIntroduction: The thyroid and parathyroid glands play a major role in maintaining physiological homeostasis in all vertebrates. Reptiles have plasma concentrations of thyroid hormones far lower than mammals. Low levels of these hormones in reptiles impede thyroid hormone detection with assays designed for the higher levels of mammals. The aim of this study was to explore teaming this with ultrasound imaging of the thyroid to appraise glandular function. Material and Methods: Thyroid function of four pond sliders was evaluated based on the results of T4 analyses and ultrasound. Results: The concentrations of T4 varied considerably between the examined animals from <9 nmol/L to >167.3 nmol/L. Ultrasound examination revealed uniform echogenicity and a smooth outline of the thyroid gland in all animals. Conclusion: Monitoring of thyroid function based on T4 and electrolyte concentrations is helpful in assessing the health and living conditions of reptiles, which is important in veterinary practice but problematic. Ultrasound examinations are useful in diagnosing changes in gland structure, such as tumours and goitres, and a combination of both methods supports comprehensive assessments of the anatomy and function of the thyroid gland.


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