甲状腺激素、促甲状腺激素释放激素和促甲状腺激素对大鼠各器官中促甲状腺激素释放激素原浓度的影响。

Mitsuma T, Hirooka Y, Yuasa K, Nogimori T

Fourth Department of Internal Medicine, Aichi Medical University, Japan.

Endocrinol Exp. 1990 Dec;24(4):395-402.

The effects of large doses of thyroid hormone, thyrotropin (TSH) or thyrotropin-releasing hormone (TRH) on pro-TRH concentrations in the rat hypothalamus, cerebrum, cerebellum, brain stem, stomach and eye were studied. The rats were administered T4 (2.5 mg/kg), T3 (375 micrograms/kg), TRH (1.0 mg/kg) or bovine TSH (1.25 IU/kg) i.p. and seven rats in each subgroup were decapitated at 4 or 24 h after the injection. Pro-TRH, TRH, TSH and thyroid hormone were measured by each radioimmunoassay. Immunoreactive pro-TRH (ir-pro-TRH) and immunoreactive TRH (ir-TRH) were found in the hypothalamus, cerebrum, brain stem, stomach and eye. Ir-pro-TRH concentrations in the hypothalamus decreased significantly after T4 and T3 injection and tended to decrease after TRH and TSH injection, but not significantly. In contrast, ir-pro-TRH concentrations in other tissues showed no changes after T4, T3, TRH or TSH injection. Ir-TRH concentrations in tissues did not change significantly after these hormone injection. The plasma TSH levels decreased significantly, while these of thyroid hormone increased significantly after thyroid hormone injection. Elution profile of acetic acid extracts of hypothalamus, stomach or eye was identical to that of synthetic pro-TRH. The findings suggest that the large dose of thyroid hormone inhibits pro-TRH synthesis in the hypothalamus, and that TRH synthesis in the tissues except the hypothalamus may not be regulated by thyroid hormone.

研究了大剂量甲状腺激素、促甲状腺激素（TSH）或促甲状腺激素释放激素（TRH）对大鼠下丘脑、大脑、小脑、脑干、胃和眼睛中前促甲状腺激素释放激素（pro-TRH）浓度的影响。给大鼠腹腔注射四碘甲状腺原氨酸（T4，2.5mg/kg）、三碘甲状腺原氨酸（T3，375μg/kg）、TRH（1.0mg/kg）或牛TSH（1.25IU/kg），每个亚组的7只大鼠在注射后4小时或24小时断头处死。通过各自的放射免疫测定法测量pro-TRH、TRH、TSH和甲状腺激素。在下丘脑、大脑、脑干、胃和眼睛中发现了免疫反应性前促甲状腺激素释放激素（ir-pro-TRH）和免疫反应性促甲状腺激素释放激素（ir-TRH）。注射T4和T3后，下丘脑ir-pro-TRH浓度显著降低，注射TRH和TSH后有降低趋势，但不显著。相反，注射T4、T3、TRH或TSH后，其他组织中的ir-pro-TRH浓度没有变化。注射这些激素后，组织中的ir-TRH浓度没有显著变化。注射甲状腺激素后，血浆TSH水平显著降低，而甲状腺激素水平显著升高。下丘脑、胃或眼睛的醋酸提取物的洗脱图谱与合成pro-TRH的洗脱图谱相同。这些发现表明，大剂量甲状腺激素抑制下丘脑pro-TRH的合成，并且除下丘脑外的组织中TRH的合成可能不受甲状腺激素的调节。