Sterling K, Tsuboyama G K, Brenner M A
Trans Assoc Am Physicians. 1984;97:332-6.
Studies were carried out on the effect of triiodothyronine (T3) on the oxygen consumption of dispersed rat liver cells incubated for 2 hr at 37 degrees C. Thyroidectomized SD-NIH rats were kept on a low iodine diet with calcium chloride in the drinking water for 4 weeks or longer to assure hypothyroidism, verified by low serum thyroxine and T3 concentrations. Liver cells were obtained by portal vein perfusion with oxygenated collagenase-enriched Krebs-Ringer-bicarbonate buffer, after the method of Berry and Friend. Cell viability was evaluated by morphology, by trypan blue exclusion, and by biochemical parameters prior to 2-hr incubations with or without added hormone. The oxygen consumption of cell suspensions was measured with the Clark oxygen electrode after the 2-hr incubations at 37 degrees C with oxygenation of the flasks and alanine (5-10 mM) as substrate. In 31 experiments the oxygen consumption (QO2) was enhanced to 121% of control values with T3 in the medium at 3.3 nM ("physiological" level) and with an even greater effect (138% of control values) with 300-1000 nM T3 ("hyperthyroid" level). Cycloheximide at 100 microM was used to inhibit new protein synthesis by incubated hepatocytes. In 18 parallel experiments with cycloheximide blockade, no alteration of the stimulatory effect of T3 was evident. The results signify that incubated liver cells show an early response to thyroid hormone by extranuclear pathways that do not require new protein synthesis.
研究了三碘甲状腺原氨酸（T3）对在37℃下孵育2小时的大鼠离体肝细胞耗氧量的影响。将甲状腺切除的SD-NIH大鼠置于低碘饮食中，饮用水中添加氯化钙，持续4周或更长时间，以确保甲状腺功能减退，通过低血清甲状腺素和T3浓度进行验证。按照Berry和Friend的方法，用富含胶原酶的充氧Krebs-Ringer-碳酸氢盐缓冲液经门静脉灌注获取肝细胞。在添加或不添加激素进行2小时孵育之前，通过形态学、台盼蓝排斥法和生化参数评估细胞活力。在37℃下孵育2小时，烧瓶通氧，以丙氨酸（5-10 mM）为底物，用Clark氧电极测量细胞悬液的耗氧量。在31个实验中，培养基中3.3 nM（“生理”水平）的T3可使耗氧量（QO2）增加至对照值的121%，300-1000 nM T3（“甲状腺功能亢进”水平）时效果更明显（为对照值的138%）。用100 microM的放线菌酮抑制孵育的肝细胞中新蛋白质的合成。在18个用放线菌酮阻断的平行实验中，T3的刺激作用没有明显改变。结果表明，孵育的肝细胞通过不需要新蛋白质合成的核外途径对甲状腺激素表现出早期反应。
