thyroid hormone (redirected from Tyroxine)

thyroid hormone

n.

A hormone, especially thyroxine or triiodothyronine, produced by the thyroid gland.

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thyroid hormone,

an iodine-containing compound secreted by the thyroid gland, predominantly as thyroxine (T₄) and, in smaller amounts, but four times more potent, triiodothyronine (T₃). These hormones increase the rate of metabolism; affect body temperature; regulate protein, fat, and carbohydrate catabolism in all cells; maintain growth hormone secretion, skeletal maturation, and the cardiac rate, force, and output; promote central nervous system development; stimulate the synthesis of many enzymes; and are necessary for muscle tone and vigor. Derivatives of thyronine, T₄ and T₃, are synthesized in the thyroid gland by a complex process involving the uptake, oxidation, and incorporation of iodide and the production of thyroglobulin, the form in which the hormones apparently are stored in thyroid follicular colloid. After the proteolysis of thyroglobulin, T₄ and T₃ are released and transported in the blood in strong, but noncovalent, association with certain plasma proteins; T₄ accounts for approximately 90% of iodine in circulation, and T₃ for 5%. All phases of the production and release of T₄ and T₃ are regulated by the thyroid-stimulating hormone secreted by the anterior pituitary gland. Production of thyroid hormones is excessive in Graves' disease and toxic nodular goiter (Plummer's disease), diminished in myxedema, and absent in cretinism. The normal 6- to 7-day half-life of T₄ in blood is reduced to 3 or 4 days in hyperthyroidism and extended to 9 or 10 days in myxedema. T₃ has a normal half-life of 2 days or less and, like T₄, is metabolized most actively in the liver. Pharmaceutic preparations of thyroid hormones extracted from animal glands and the synthetic compounds levothyroxine sodium and liothyronine sodium are used as replacement therapy in patients with hypothyroidism. The dosage is initially low and is gradually increased to the optimal level based on the patient's clinical response and tests of the findings on thyroid function studies. Overdosage or a rapid increase in the dosage may result in signs of hyperthyroidism, such as nervousness, tremor, tachycardia, cardiac arrhythmia, and menstrual irregularity.

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thyroid hormone (thīˑ·roid hōrˑ·mōn),

n a combination of two hormones, triiodothyronine (T3) and thyroxine (T4), produced by the thyroid gland. These hormones are responsible for modulating basal metabolic rate and can influence blood pressure, heart rate, temperature, and weight. See also therapy, Gerson.

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Patient discussion about thyroid hormone.

Q. Has anyone tried natural hormones for hypo-thyroidism or fibromyalgia? I am on the low normal range for hypo-thyroidism (do not take meds for) and was diagnosed years ago with fibromyalgia. I take Ultram for the pain which also helps my fatigue factor but I still feel so sluggish sometimes and just want to sleep. I'm on an anti-depressant as it is. I've been hearing more about natural hormone therapy for these conditions and was wondering if anyone out there has tried this.

A. The Ultram and the anti-depressants do that and as for the natural hormone treatments they don't really work. The Gulf War that gave me hypo-thyroid and hypo-prolactimia which is the Pituitary Gland acting up. On top of the fibro,fatique,pain and recovering from arsenic poison I was put on hormone treatments and it made things worse. I blew up like a balloon, I was still tired and it never corrected the problem with my glands. I tried everything out there and I wasn't getting any better until now. A friend of mine told me of this product called Vitalitea and that it could help me.I was desperate to get my health back and boy did I. Go to Ai3global.com/greentea and click on product and wellness and read it. Check out the www on the healing properties of quality green tea and not the stuff you by at the local store. My fatique, and chronic pain is gone. My Fibromyalgia is so, so mild. I do fun things again after 7 year of suffering. You won't regret it. It is all natural.