L-チロキシン 化学特性,用途語,生産方法
解説
O-(4-hydroxy-3,5-diiodophenyl)-3,5-diiodo-L-tyrosine．C15H11NO4I4(776.87)．L-チロキシンは，甲状せんホルモンの一つ．甲状腺内に存在するチログロブリンのペプチド内にアミノ酸残基として存在し，酵素の作用により3,5,3′-トリヨードチロニンなどと一緒に遊離の状態で血液中に放出される．チログロブリンのトリプシンによる加水分解，甲状腺の水酸化バリウムによる加水分解により得られる．分解点235～236 ℃．[α]20D－4.4°(0.13 mol L－1 水酸化ナトリウム-70％ エタノール)．pI4.5．水，エタノールに不溶．酸，アルカリ存在下でエタノールに溶解する．アルカリに安定，酸に不安定でヨウ素を分離する．生理作用は複雑であり，動物の新陳代謝を促進する．チロキシンが欠乏すると甲状腺腫，甲状腺機能低下症，クレチン病，粘液水腫などをきたすので，これらの症状の治療に使用する．森北出版「化学辞典（第2版）
用途
甲状腺ホルモン
効能
甲状腺ホルモン補充薬
説明
L-Thyroxine is a synthetic form of the thyroid hormone thyroxine.
In vivo, L-thyroxine (0.9 and 2.7 μg) inhibits synthesis and release of thyrotropin induced by thyrotropin-releasing hormone from the anterior pituitary in mice. It also reverses decreases in levels of circulating thymic serum factor (FTS) and the number of T rosette-forming cells in an old age-induced mouse model of hypothyroidism. Formulations containing L-thyroxine have been used in the treatment of hypothyroidism.
化学的特性
Crystalline Solid
使用
One of the thyroid hormones involved in the maintenance of metabolic homeostasis. Synthesized and stored as amino acid residues of thyroglobulin, the major protein component of the thyroid follicular
colloid. Synthesis and secretion are regulated by the pituitary hormone (TSH). Deiodinated in peripheral tissues to the active metabolite, liothyronine. The D-form has very little activity as a thyroi
d hormone, but has been used to treat hyperlipidemia.
定義
ChEBI: The L-enantiomer of thyroxine.
適応症
Effects of this drug depend heavily on dosage. In small doses, levothyroxine exhibits anabolic
action. In medium doses, it stimulates growth and development of tissue, metabolism
of protein, fats, and carbohydrates, increases functional activity of central nervous and cardiovascular
systems, as well as kidneys and liver. In large doses, it slows the thyrotropic
activity of the hypophysis and suppresses thyroid gland production. Levothyroxine is used
for hypothyroidism, myxedema, thyrotoxicosis, erythyroid conditions, and cretinism.
薬物動態学
Because of its firmer binding to carrier proteins, synthetic crystalline L-T4 sodium salt (levothyroxine
sodium, Synthtoid, Euthyrox) has a slower onset of action than crystalline T3 or a desiccated thyroid
preparation. Its administration leads to a greater increase in serum T4 but a lesser increase in serum T3
than compared with Thyroid USP. The availability of 11 different tablet strengths, ranging from 25 to
300 μg, allows individual dosing
純化方法
Purification is the same as for the D-isomer above. Likely impurities are tyrosine, iodotyrosine, iodothyroxines and iodide. Dissolve it in dilute ammonia at room temperature, then crystallise it by adding di[] 546 +27.8o (c 5, EtOH). [Harrington et al. Biochem J 39 164 1945, Nahm & Siedel Chem Ber 96 1 1963, Reineke & Turner J Biol Chem 161 613 1945, Chalmers et al. J Chem Soc 3424 1949, Beilstein 14 II 378, 14 III 1566, 14 IV 2373.]
L-チロキシン 上流と下流の製品情報
原材料
準備製品