ANTITHYROID AND GOITROGENIC EFFECTS OF MILLET - ROLE OF C-GLYCOSYLFLAVONES
ANTITHYROID AND GOITROGENIC EFFECTS OF MILLET - ROLE OF C-GLYCOSYLFLAVONES
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DOI：
10.1210/jcem-68-4-707
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发表时间：
1989-04-01
影响因子：
5.8
通讯作者：
KUBOTA, K
中科院分区：
文献类型：
--
作者：
GAITAN, E;LINDSAY, RH;KUBOTA, K
珍珠粟[P.]小米（L. leeke）是半干旱热带许多地区农村贫困人口的主要食物能量来源。流行病学证据表明，小米可能在这些地区地方性甲状腺肿的发生中起作用，并且在大鼠中进行的少量实验数据支持这一怀疑。本研究采用猪甲状腺片和甲状腺过氧化物酶（TPO）测定法测定了大鼠体内和体外的谷子日粮、谷子提取物和其中所含的某些纯化合物的甲状腺肿和抗甲状腺作用。为了在这些研究中使用，全谷物小米逐渐去皮，连续产生四种麸皮和四种面粉，其中直接分析显示c -糖基黄酮的浓度逐渐降低。体内饲喂c -糖基黄酮含量最高的麸皮组分1，可显著增加甲状腺重量并增强抗甲状腺作用。饲喂c -糖基黄酮第二丰富的麸皮部分2，也产生了类似但不太明显的变化。猪甲状腺片对125I代谢的体外研究表明，麸皮部分1和2的提取物最有效，产生的变化与甲巯咪唑（MMI）产生的变化相似。浓度为60。mol/L，谷子中主要的c -糖基黄酮葡糖苷的效果与1 .mu的效果相当。mol / L MMI。43 .同样，在猪TPO的研究中，麸皮提取物1对酶活性的抑制作用显著（85%），而麸皮提取物2、3和4对酶活性的抑制作用逐渐减弱。综上所述，谷子各组分的tpo抑制活性与其c -糖基黄酮浓度密切相关。谷子中的三种c -糖基黄酮，糖基黄素、糖基黄素和玻璃黄素也能抑制TPO活性。因此，体内和体外研究表明，富含c -糖基黄酮的小米饮食具有类似于某些其他抗甲状腺药物和小剂量MMI的致甲状腺肿和抗甲状腺作用。我们得出的结论是，在碘缺乏的地区，小米是饮食的主要组成部分，它的摄入可能有助于甲状腺肿的发生。
Pearl millet [P. millet (L.) leeke] is the main source of food energy for the rural poor in many areas of the semiarid tropics. Epidemiological evidence suggests that millet may play a role in the genesis of endemic goiter in these areas, and sparse experimental data in rats support this suspicion. This study was undertaken to determine in vivo in rats and in vitro using porcine thyroid slices and a thyroid peroxidase (TPO) assay the goitrogenic and antithyroid effects of millet diets, extracts of millet, and certain pure compounds contained therein. For use in these studies, whole grain millet was progressively dehulled to yield successively four bran and four flour fractions in which direct analyses revealed progressively lower concentrations of C-glycosylflavones. In vivo feeding of bran fraction 1, that richest in C-glycosylflavones, led to a significant increase in thyroid weight and antithyroid effects. Feeding of bran fraction 2, the next richest in C-glycosylflavones, produced similar, but less marked, changes. In vitro studies of 125I metabolism using porcine thyroid slices indicated that extracts of bran fractions 1 and 2 were most potent, producing changes similar to those produced by methimazole (MMI). At a concentration of 60 .mu.mol/L, glucosylvitexin, the major C-glycosylflavone present in millet, had effects comparable to those of 1 .mu.mol/L MMI. 43 ySimilarly, in studies of porcine TPO, extracts of bran fraction 1 caused pronounced (85%) inhibition of enzyme activity, and progressively less inhibition was induced by extracts of bran fractions 2, 3, and 4. Overall, the TPO-inhibiting activities of the various millet fractions closely correlated with their C-glycosylflavone concentrations. Three C-glycosylflavones present in millet, glucosylvitexin, glycosylorientin, and vitrexin, also inhibited TPO activity. Thus, in vivo and in vitro studies revealed that millet diets rich in C-glycosylflavones produce goitrogenic and antithyroid effects similar to those of certain other antithyroid agents and small doses of MMI. We conclude that in areas of iodine deficiency in which millet is a major component of the diet, its ingestion may contribute to the genesis of edemic goiter.