EVIDENCE FOR THYROID-HORMONE DEFICIENCY IN IRON-DEFICIENT ANEMIC RATS
EVIDENCE FOR THYROID-HORMONE DEFICIENCY IN IRON-DEFICIENT ANEMIC RATS
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DOI：
10.1093/jn/119.5.772
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发表时间：
1989-05-01
影响因子：
4.2
通讯作者：
GREEN, W
中科院分区：
文献类型：
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作者：
BEARD, J;TOBIN, B;GREEN, W
缺铁性贫血大鼠先前已被证明具有低血浆甲状腺激素水平和血浆甲状腺激素对急性冷暴露的不良反应。作为初步探索，我们从三个方面研究了年龄匹配的大鼠缺铁时的甲状腺激素代谢：1）血浆TSH（促甲状腺激素，甲状腺刺激素），T4（甲状腺素）和T3（三碘甲状腺原氨酸）对不同剂量外源性TRH（促甲状腺激素释放激素）的反应，2）血浆T3动力学，3）肝脏T3产生率。缺铁性贫血大鼠有较低的基础TSH值和钝化TSH反应静脉注射TRH在三个不同的剂量（10，25和50 ng TRH/100克体重）。缺铁性贫血大鼠的血浆T3周转率也显著降低（对照组为42对88 ng/h），肝T4- 5“脱碘酶活性也显著低于对照组[26对44.0 ng T3/（mg蛋白）]。20分钟）]。因此，在缺铁性贫血大鼠T3生产率下降，如营业额研究所记录，可能与脱碘酶活性降低和T3外周形成减少。抑制TSH对TRH的反应进一步促进或延续这种T3缺乏。我们认为这种异常的甲状腺状态是缺铁性贫血产热受损的部分原因。
Iron-deficient anemic rats have previously been shown to have low plasma levels of thyroid hormone and a poor plasma thyroid hormone response to acute cold exposure. As an initial exploration, we examined thyroid hormone metabolism during iron deficiency in age-matched rats from three aspects: 1) plasma TSH (thyrotropin, thyroid stimulating hormone), T4 (thyroxine) and T3 (triiodothyronine) responses to graded doses of exogenous TRH (thyrotropin releasing hormone), 2) plasma T3 kinetics, and 3) rates of hepatic T3 production. Iron-deficient anemic rats had lower basal TSH values and blunted TSH responses to intravenous TRH injection at three different doses (10, 25 and 50 ng TRH/100 g body wt). Iron-deficient anemic rats also had a significant decrease in plasma T3 turnover (42 vs. 88 ng/h in controls), and significantly lower hepatic T4-5''deiodinase activities than controls [26 vs. 44.0 ng T3/(mg protein .cntdot. 20 min)]. Thus, decreased rates of T3 production in iron-deficient anemic rats, as documented by turnover studies, may be related to decreased deiodinase activity and reduced peripheral formation of T3. The dampened TSH responses to TRH further facilitate or perpetuate this T3 deficiency. We propose that this abnormal thyroid state is partially responsible for impaired thermogenesis in iron-deficiency anemia.