Shapiro L E, Wasserman S H, Katz C P, Surks M I
Department of Medicine, Montefiore Medical Center, Bronx, New York 10467.
Endocrinology. 1989 Feb;124(2):1026-32. doi: 10.1210/endo-124-2-1026.
The heat shock (HS) response is a characteristic disruption of protein synthesis which occurs in cells exposed to a variety of noxious stimuli. The effects of HS on thyroid hormone-responsive GC cells were studied in an attempt to devise an in vitro model for the adaptive changes in thyroid hormone action caused by nonthyroidal disease. HS enhanced GC cell synthesis of 70 K and 90 K proteins in a manner previously described as characteristic of the HS response in many tissues. A step-wise decrease in GC cell viability occurred when cells were exposed to 45 C for 10 to 35 min. HS (45 C, 20 min) resulted in a rapid decrease in binding of T3 to nuclear receptors. Two hours after HS, analysis of T3 binding to isolated nuclei showed a 50% fall in binding capacity (240 fmol/100 micrograms DNA) compared to non-HS control cells (540 fmol/100 micrograms DNA); no difference in dissociation constant (Kd) was observed. The effect of thyroid hormone on cell viability after HS was then determined. Thyroid hormone depletion (less than or equal to 0.02 nM T3) resulted in significantly (P less than 0.05) enhanced cell viability compared to cells cultured with physiological T3 (0.2 nM) after incubation at 45 C for intervals of 10-35 min. This inverse relationship between medium T3 content and cell tolerance of HS occurred over a wide range of T3 concentrations. Mean cell viability after exposure to 45 C for 20 min was 44 +/- 3% in T3-depleted cultures (less than or equal to 0.02 nM), 27 +/- 1% to 32 +/- 5% in cultures containing 0.07-0.5 nM T3, and 13 +/- 3% in cultures containing 5 nM T3. Our results thus characterize the response to HS in GC cells and the relationship of this response to medium T3. Similar to the effect of various nonthyroidal diseases on rat hepatocytes in vivo, HS resulted in a decrease in T3 nuclear receptors. Similar to the adverse effect of thyroid hormone on morbidity in animals with experimental diseases or injury, GC cell viability after HS was inversely related to medium T3 content. Thus the HS response in GC cells may be a valuable in vitro model relevant to the effect on thyroid hormone action caused by nonthyroidal disease.
热休克（HS）反应是蛋白质合成的一种特征性破坏，发生在暴露于各种有害刺激的细胞中。研究了热休克对甲状腺激素反应性GC细胞的影响，试图设计一种体外模型，用于研究非甲状腺疾病引起的甲状腺激素作用的适应性变化。热休克以先前描述的许多组织中热休克反应的特征方式增强了GC细胞中70K和90K蛋白的合成。当细胞在45℃下暴露10至35分钟时，GC细胞活力呈逐步下降。热休克（45℃，20分钟）导致T3与核受体的结合迅速减少。热休克后两小时，对分离细胞核的T3结合分析显示，与非热休克对照细胞（540fmol/100μgDNA）相比，结合能力下降了50%（240fmol/100μgDNA）；未观察到解离常数（Kd）的差异。然后确定了热休克后甲状腺激素对细胞活力的影响。与在45℃下孵育10 - 35分钟后用生理浓度T3（0.2nM）培养的细胞相比，甲状腺激素耗竭（小于或等于0.02nM T3）导致细胞活力显著增强（P小于0.05）。培养基T3含量与热休克细胞耐受性之间的这种反比关系在很宽的T3浓度范围内都存在。在T3耗竭的培养物（小于或等于0.02nM）中，暴露于45℃20分钟后的平均细胞活力为44±3%，在含有0.07 - 0.5nM T3的培养物中为27±1%至32±5%，在含有5nM T3的培养物中为13±3%。因此，我们的结果描述了GC细胞对热休克的反应以及这种反应与培养基T3的关系。与各种非甲状腺疾病对大鼠体内肝细胞的影响类似，热休克导致T3核受体减少。与甲状腺激素对患有实验性疾病或损伤的动物发病率的不利影响类似，热休克后GC细胞活力与培养基T3含量呈反比。因此，GC细胞中的热休克反应可能是一种有价值的体外模型，与非甲状腺疾病对甲状腺激素作用的影响相关。
