Mitsuma T, Nogimori T, Chaya M
Endocrinol Exp. 1985 Jun;19(2):83-90.
The effects of dermorphin on thyrotropin-releasing hormone (TRH) and thyrotropin (TSH) secretion in rats were studied. Dermorphin (400 micrograms kg-1) was injected i. v. and the rats were serially decapitated. TRH, TSH and thyroid hormones were measured by radioimmunoassay. The hypothalamic immunoreactive TRH (ir-TRH) content decreased significantly after dermorphin injection, whereas its plasma concentration tended to decrease, but not significantly. The plasma TSH levels decreased significantly in a dose-related manner with a nadir at 40 min after the injection. The plasma thyroid hormone levels were not changed significantly. The plasma ir-TRH and TSH responses to cold were inhibited by dermorphin, but the plasma TSH response to TRH was not. Naloxone partially blocked the inhibitory effect of dermorphin on TSH levels. In the para-chlorophenylalanine or pimozide pretreated groups the inhibitory effect of dermorphin on TSH levels was prevented, but not in the groups pretreated with 5-hydroxytryptophan or L-DOPA. These drugs alone did not affect plasma TSH levels in terms of the dose used. The inactivation of TRH immunoreactivity by plasma of hypothalamus in vitro after dermorphin injection did not differ from that of the control. These findings suggest that dermorphin acts on the hypothalamus to inhibit TRH release, and its effects are mediated via opioid receptor and modified by amines of the central nervous system.
研究了德莫啡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。静脉注射德莫啡（400微克/千克），并对大鼠进行连续断头处死。采用放射免疫分析法测定TRH、TSH和甲状腺激素。注射德莫啡后，下丘脑免疫反应性TRH（ir-TRH）含量显著降低，而其血浆浓度有降低趋势，但不显著。血浆TSH水平在注射后40分钟以剂量相关方式显著降低，最低值出现于此。血浆甲状腺激素水平无显著变化。德莫啡抑制了血浆ir-TRH和TSH对寒冷的反应，但未抑制血浆TSH对TRH的反应。纳洛酮部分阻断了德莫啡对TSH水平的抑制作用。在对氯苯丙氨酸或匹莫齐特预处理组中，德莫啡对TSH水平的抑制作用被阻止，但在5-羟色氨酸或左旋多巴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。注射德莫啡后，下丘脑血浆对TRH免疫反应性的体外失活与对照组无差异。这些发现表明，德莫啡作用于下丘脑以抑制TRH释放，其作用通过阿片受体介导，并受中枢神经系统胺类物质的调节。
