Litten R Z, Carr F E, Fein H G, Smallridge R C
Department of Physiology, Armed Forces Radiology Research Institute, Bethesda, MD 20814.
Life Sci. 1990;47(16):1409-17. doi: 10.1016/0024-3205(90)90519-w.
The effect of radiation-induced anorexia on serum thyrotropin (TSH), pituitary TSH-beta mRNA, pituitary TSH content, serum thyroxine (T4), and serum 3,5,3'-triiodothyronine (T3) was investigated using feed-matched controls. Rats received 10 Gy gamma whole-body irradiation and were examined 1-3 days postirradiation. Feed-matched and untreated controls were also studied. The average food intake of the irradiated and feed-matched groups was approximately 18% of the untreated controls. Over the three day period both the irradiated and feed-matched groups lost a significant amount of body weight. The serum T4 levels of both the irradiated and feed-matched groups were not significantly different from each other, but were significantly depressed when compared to the untreated control group. The serum TSH and T3 were, however, significantly greater in the irradiated than the feed-matched groups at day 3 posttreatment. To determine if the difference in the serum TSH level between the two groups was due to a pretranslational alteration in TSH production, we measured the TSH-beta mRNA using an RNA blot hybridization assay. We found that the TSH-beta mRNA level was the same in the irradiated and feed-matched groups, suggesting that the mechanism responsible for the radiation-induced increase in the serum TSH level is posttranscriptional. Pituitary TSH content in the irradiated rats was significantly less than in pair-fed controls, suggesting that irradiation may permit enhanced secretion of stored hormone.
使用饲料匹配的对照组研究了辐射诱导的厌食对血清促甲状腺激素（TSH）、垂体TSH-β mRNA、垂体TSH含量、血清甲状腺素（T4）和血清3,5,3'-三碘甲状腺原氨酸（T3）的影响。大鼠接受10 Gy的全身γ射线照射，并在照射后1-3天进行检查。还研究了饲料匹配的对照组和未处理的对照组。照射组和饲料匹配组的平均食物摄入量约为未处理对照组的18%。在三天的时间里，照射组和饲料匹配组的体重均显著下降。照射组和饲料匹配组的血清T4水平彼此之间无显著差异，但与未处理的对照组相比显著降低。然而，在治疗后第3天，照射组的血清TSH和T3显著高于饲料匹配组。为了确定两组血清TSH水平的差异是否是由于TSH产生的转录前改变所致，我们使用RNA印迹杂交测定法测量了TSH-β mRNA。我们发现照射组和饲料匹配组的TSH-β mRNA水平相同，这表明辐射诱导血清TSH水平升高的机制是转录后机制。照射大鼠的垂体TSH含量显著低于配对喂养的对照组，这表明照射可能使储存激素的分泌增强。
