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Micronutrients and Nutraceuticals: Effects on Exercise Performance
Published in Peter M. Tiidus, Rebecca E. K. MacPherson, Paul J. LeBlanc, Andrea R. Josse, The Routledge Handbook on Biochemistry of Exercise, 2020
Stella L. Volpe, Quentin Nichols
Iron is also involved in thyroid hormone production. Thyroid hormones are involved in nearly every process in the body, including energy metabolism and thermoregulation. Specifically, iron-deficiency anaemia can negatively affect thyroid peroxidase (TPO) activity. Thyroid peroxidase is a haem-containing enzyme. If TPO activity is impaired, thyroid-stimulating hormone (TSH) activity will be increased and thyroxine (T4) and triiodothyronine (T3) activity will be decreased (37). Therefore, iron-deficiency anaemia may lead to a decreased resting metabolic rate (RMR) and impaired thermoregulation, especially under cold conditions (9, 53).
The patient with acute endocrine problems
Published in Peate Ian, Dutton Helen, Acute Nursing Care, 2020
Two pairs of parathyroid glands are embedded in the posterior surface of the thyroid gland (see Figure 11.3). The thyroid makes and stores thyroid hormones (T3 and T4), and it is able to hold up to a 100 days’ supply. Iodine is necessary for the production of thyroid hormones. Thyroid hormones affect virtually every organ in the body and increase metabolic rate. The parathyroid glands produce parathyroid hormone (PTH), which regulates serum calcium levels. PTH secretion is stimulated when ionised serum calcium falls. This hormone influences the bones and the kidneys, leading to restoration of normal calcium levels (bone resorption and increased renal tubular calcium reabsorption, respectively).
Medical Management of Thyroid Disorders
Published in Madan Laxman Kapre, Thyroid Surgery, 2020
Himanshu Patil, Shailesh Pitale
Thyroid hormone measurements include total T4, total T3, and TSH. Recent advances now allow direct measurement of free T4 which is a superior technique. Total T4 measurements are affected by hormone blinding proteins, drugs (oral contraceptive pills [OCPs], androgens, and opiates) and medical conditions like hepatitis, cirrhosis, and nephrotic syndrome. Free T4 levels are unchanged in these circumstances. Approximately 5% of patients will have normal serum free T4 levels and elevated serum T3 levels.
Using the Biopsychosocial Approach to Identify Factors Associated with Major Depressive Disorder for Individuals with Hypothyroidism
Published in Issues in Mental Health Nursing, 2022
Kennedy S. Anderson, Krista J. Howard, Kelly B. Haskard-Zolnierek, Julia Pruin, Rebecca G. Deason
Hypothyroidism, or underactive thyroid, is described as a deficiency of thyroid hormones (American Thyroid Association, 2020). A diagnosis of hypothyroidism is made following a blood test to assess the function of thyroid stimulating hormone (TSH), and treatment typically consists of the thyroid hormone supplement thyroxine (T4) while some patients also are given the additional triiodothyronine (T3) supplement. Common physical symptoms of hypothyroidism include lethargy, sensitivity to cold, constipation, dry skin, weight gain, sexual dysfunction, and neck swelling (Ali et al., 2017; El Saide Sayyah et al., 2013). Hypothyroidism has also been implicated in changes in mood and cognition, such as poorer attention, memory, and executive function and increased rates of anxiety and depression (Samuels, 2014).
Thyroid functions as a parameter in monitoring of antiepileptic drugs
Published in Neurological Research, 2022
Ekim Comert, Ulufer Celebi, Bilge Piri Cinar, Mustafa Acikgoz, Esra Aciman Demirel, Huseyin Tugrul Atasoy
Many studies have been conducted on the negative impacts of AEDs on the hematological, endocrinological, and central nervous systems, as well as the ligaments of the body. The aim of this study was to evaluate the effects of antiepileptic therapy on thyroid function in epileptic patients. Synthesis of thyroid hormones takes place in the thyroid gland under the control of the hypothalamic–pituitary axis, and thyrotropin-releasing hormone produced by the hypothalamus stimulates TSH release from the hypophysis gland. T4 hormone is released from the thyroid gland and is converted into T3 hormone, which is a more active hormone with deiodinase enzyme in peripheral tissues [7]. T3 and T4 circulate through the blood in two forms: freely or bound. More than 99.8% of the thyroid hormone circulating in blood is bound to the plasma proteins thyroxine-binding globulin (TBG), transthyretin, and albumin. Less than 1% of the hormone in a free solution is in equilibrium with bound hormone [5].
Thyroid-disrupting effects of chlorpyrifos in female Wistar rats
Published in Drug and Chemical Toxicology, 2022
Joice Karina Otênio, Karine Delgado Souza, Odair Alberton, Luiz Rômulo Alberton, Karyne Garcia Tafarelo Moreno, Arquimedes Gasparotto Junior, Rhanany Alan Calloi Palozi, Emerson Luiz Botelho Lourenço, Ezilda Jacomassi
Thyroid hormones are produced in a process that involves the active transport of iodine into follicles through the specific transmembrane transporter sodium/iodide symporter, followed by the oxidation and incorporation of tyrosine residues in the thyroglobulin molecule. This iodination of tyrosine results in monoiodinated (MIT) and diiodinated (DIT) residues that are enzymatically bound to form T3 and T4 (Köhrle et al.2018). Iodinated thyroglobulin that contains MIT, DIT, T3, and T4 is stored as an extracellular polypeptide in colloids near the lumen of thyroid follicular cells. Hormone release occurs through endocytosis and the lysosomal digestion of thyroglobulin in follicular cells. Although the thyroid gland preferentially produces T4, the main circulating thyroid hormone is T3 (Yavuz et al.2019). More than 99% of T3 and T4 combine immediately with various plasma proteins, including thyroxine-binding globulin, thyroxine-binding prealbumin, and albumin. Thus, T3 and T4 levels can be measured as a total (free + bound protein) or as a free fraction (Mullur et al.2014).