Influence of thyroid status on dopaminergic inhibition of thyrotropin and prolactin secretion: evidence for an additional feedback mechanism in the control of thyroid hormone secretion.
Influence of thyroid status on dopaminergic inhibition of thyrotropin and prolactin secretion: evidence for an additional feedback mechanism in the control of thyroid hormone secretion.
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甲状腺状态对促甲状腺素和催乳素分泌的多巴胺能抑制的影响：控制甲状腺激素分泌的额外反馈机制的证据。
DOI：
10.1210/jcem-51-3-585
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发表时间：
1980
期刊：
影响因子：
--
通讯作者：
A. Toft
中科院分区：
文献类型：
--
作者：
C. Feek;J. Sawers;N. Brown;J. Seth;W. Irvine;A. Toft
在连续3天随机口服甲氧氯普胺、左旋多巴或安慰剂后，对5例明显原发性甲状腺功能减退患者（血清总T4低、血清TSH升高）和5例亚临床甲状腺功能减退患者（血清总T4正常、血清TSH升高）进行血清TSH和PRL浓度测定。在两组中，与安慰剂相比，甲氧氯普胺后血清TSH和PRL浓度升高，左旋多巴后血清TSH和PRL浓度下降。然而，与明显甲状腺功能减退患者相比，亚临床甲状腺功能减退患者血清TSH和PRL浓度的升高明显更大。在两组服用左旋多巴后，这些垂体激素的下降程度不可能有任何显著差异。这些结果表明，除了在垂体前叶甲状腺素水平上建立甲状腺激素的负反馈外，下丘脑还存在先前未被认识到的甲状腺激素作用，导致多巴胺能抑制TSH释放的增加。甲状腺激素刺激下丘脑多巴胺也会抑制PRL的分泌。
Serum TSH and PRL concentrations were measured after the randomized oral administration of either metoclopramide, L-dopa, or placebo on 3 consecutive days to five patients with overt primary hypothyroidism (low serum total T4 and raised serum TSH) and to five patients with subclinical hypothyroidism (normal serum total T4 and raised serum TSH). In both groups there was a rise in serum TSH and PRL concentrations after metoclopramide and a fall after L-dopa when compared with the effect of the placebo. However, the rise in serum TSH and PRL concentrations was significantly greater in patients with subclinical hypothyroidism compared to that in patients with overt hypothyroidism. It was not possible to show any significant difference in the degree of fall of these pituitary hormones after L-dopa administration in the two groups. These results suggest that in addition to the established negative feedback of thyroid hormones at the level of anterior pituitary thyrotropes, there is a previously unrecognized effect of thyroid hormones at the hypothalamus, resulting in increased dopaminergic inhibition of TSH release. Stimulation of hypothalamic dopamine by thyroid hormones also inhibits PRL secretion.