Vagenakis A G
Department of Medicine, University of Patras Medical School, Greece.
Acta Med Austriaca. 1988;15 Suppl 1:52-6.
Recent developments in thyroid hormone metabolism have helped to understand the complex events which characterize the regulation of TSH secretion. Plasma T3 concentration as well as intrapituitary T3 generation from T4, exert a profound effect on TSH synthesis and release. Pituitary Type II deiodinase differs from Type I deiodinase found in other tissue such as liver and kidney, and in fact different conditions such as hypothyroidism and hyperthyroidism affect these enzymes in opposite direction. Thyroid hormones exert other effects on the pituitary such as increased synthesis of substance P, increased synthesis of GH, and decreased TRH receptors, TRH also modifies its own receptors in the pituitary and exerts modulatory effects on TSH molecule. Patients with non thyroidal illness may display TSH molecules with decreased biological activity. Various agents used in every day praxis may alter TSH and thyroid secretion. The physician must be aware of changes in order to avoid diagnostic pitfalls.
甲状腺激素代谢的最新进展有助于理解促甲状腺激素（TSH）分泌调节所特有的复杂事件。血浆三碘甲状腺原氨酸（T3）浓度以及由甲状腺素（T4）在垂体内部生成的T3，对TSH的合成和释放具有深远影响。垂体II型脱碘酶不同于在肝脏和肾脏等其他组织中发现的I型脱碘酶，事实上，诸如甲状腺功能减退和甲状腺功能亢进等不同状况对这些酶的影响方向相反。甲状腺激素对垂体还具有其他作用，如增加P物质的合成、增加生长激素（GH）的合成以及减少促甲状腺激素释放激素（TRH）受体，TRH也会改变其在垂体中的自身受体，并对TSH分子发挥调节作用。非甲状腺疾病患者可能表现出生物活性降低的TSH分子。日常实践中使用的各种药物可能会改变TSH和甲状腺分泌。医生必须了解这些变化，以避免诊断失误。
