Mitsuma T, Nogimori T, Chaya M
Exp Clin Endocrinol. 1985 Jun;85(3):319-25. doi: 10.1055/s-0029-1210457.
The effects of physalaemin on thyrotropin-releasing hormone (TRH) and thyrotropin (TSH) secretion were studied in rats. Physalaemin (150 micrograms/kg) was injected iv, and the rats were serially decapitated. TRH, TSH and thyroid hormone were measured by radioimmunoassay. The hypothalamic immunoreactive TRH (ir-TRH) contents increased significantly after physalaemin injection, whereas its plasma concentrations tended to decrease, but not significantly. The plasma TSH levels decreased significantly in a dose-related manner with a nadir at 30 min. The plasma ir-TRH and TSH responses to cold were inhibited by physalaemin, but the plasma TSH response to TRH was not affected. The plasma thyroid hormone levels did not change significantly. In the pimozide- or para-chlorophenylalanine-pretreated group, the inhibitory effect of physalaemin on TSH levels was prevented, but not in the L-DOPA- or 5-hydroxytryptophan-pretreated group. These drugs alone did not affect plasma TSH levels in terms of the dose used. The inactivation of TRH immunoreactivity by the hypothalamus or plasma in vitro after physalaemin injection did not differ from that of the control. These findings suggest that physalaemin acts on the hypothalamus to inhibit TRH release, and its effects are at least partially modified by amines of the central nervous system.
研究了 Physalaemin 对大鼠促甲状腺激素释放激素（TRH）和促甲状腺激素（TSH）分泌的影响。静脉注射 Physalaemin（150 微克/千克），然后对大鼠依次断头。采用放射免疫分析法测定 TRH、TSH 和甲状腺激素。注射 Physalaemin 后，下丘脑免疫反应性 TRH（ir-TRH）含量显著增加，而其血浆浓度有下降趋势，但不显著。血浆 TSH 水平呈剂量依赖性显著下降，在 30 分钟时降至最低点。Physalaemin 抑制了血浆 ir-TRH 和 TSH 对寒冷的反应，但血浆 TSH 对 TRH 的反应未受影响。血浆甲状腺激素水平无显著变化。在匹莫齐特或对氯苯丙氨酸预处理组中，Physalaemin 对 TSH 水平的抑制作用被阻止，但在左旋多巴或 5-羟色氨酸预处理组中未被阻止。就所用剂量而言，这些药物单独使用时不影响血浆 TSH 水平。注射 Physalaemin 后，下丘脑或血浆在体外对 TRH 免疫反应性的灭活与对照组无差异。这些发现表明，Physalaemin 作用于下丘脑以抑制 TRH 释放，其作用至少部分受中枢神经系统胺类的调节。
