Taguchi M, Field J B
Department of Medicine, St Luke's Episcopal Hospital, Houston, TX 77225-0269.
Metabolism. 1990 Apr;39(4):418-24. doi: 10.1016/0026-0495(90)90258-e.
Thyrotropin (TSH) and carbachol stimulated in a dose-dependent manner the accumulation of 3H-glycerophosphoinositol (GPI), 3H-inositol monophosphate (IP1), 3H-inositol bisphosphate (IP2) and 3H-inositol trisphosphate (IP3) in primary cultures of dog thyroid cells prelabeled with myo-[2-3H]inositol. TSH, 250 mU/mL, stimulated 3H-IP3 level after a 10-minute incubation while 10 mU/mL TSH increased it during a 60-minute incubation. The effect of carbachol was more rapid and greater than that of TSH. Carbachol, 100 mumol/L, elevated 3H-IP3 after a 2-minute incubation and 3H-IP3 formation was increased by as little as 1 mumol/L carbachol. TSH stimulation was observed only if the cells were deprived of TSH for 5 days before being labeled with 3H-inositol. Prolongation of the labeling period or addition of TSH, (Bu)2cAMP or carbachol during the labeling increased 3H-inositol incorporation into polyphoinositides (PIPs). When the cells were labeled without any other addition, control and TSH-stimulated 3H-IP3 levels increased in parallel with 3H-PIP levels. However, TSH or carbachol-stimulated 3H-IP3 levels did not increase in proportion to 3H-PIPs level when the cells were labeled with TSH or (Bu)2cAMP. Thus, the ratio of 3H-IP3/3H-PIPs (both control and TSH or carbachol-stimulated) decreased in the cells labeled with TSH or (Bu)2cAMP, which might reflect TSH stimulation of 3H-inositol incorporation into PIPs pool(s) that do not participate in hormone-induced hydrolysis of PIPs.(ABSTRACT TRUNCATED AT 250 WORDS)
促甲状腺激素（TSH）和卡巴胆碱以剂量依赖的方式刺激用肌醇-[2-³H]肌醇预标记的犬甲状腺细胞原代培养物中³H-甘油磷酸肌醇（GPI）、³H-肌醇单磷酸（IP1）、³H-肌醇二磷酸（IP2）和³H-肌醇三磷酸（IP3）的积累。250 mU/mL的TSH在孵育10分钟后刺激³H-IP3水平，而10 mU/mL的TSH在孵育60分钟期间使其升高。卡巴胆碱的作用比TSH更快且更强。100 μmol/L的卡巴胆碱在孵育2分钟后使³H-IP3升高，低至1 μmol/L的卡巴胆碱就能增加³H-IP3的形成。仅当细胞在用³H-肌醇标记前5天未接触TSH时，才能观察到TSH刺激。标记期的延长或在标记期间添加TSH、双丁酰环磷腺苷（Bu）2cAMP或卡巴胆碱会增加³H-肌醇掺入多磷酸肌醇（PIPs）。当细胞在无任何其他添加物的情况下进行标记时，对照和TSH刺激的³H-IP3水平与³H-PIP水平平行增加。然而，当细胞用TSH或（Bu）2cAMP标记时，TSH或卡巴胆碱刺激的³H-IP3水平与³H-PIPs水平不成比例增加。因此，在用TSH或（Bu）2cAMP标记的细胞中，³H-IP3/³H-PIPs（对照以及TSH或卡巴胆碱刺激的）比值降低，这可能反映了TSH刺激³H-肌醇掺入不参与激素诱导的PIPs水解的PIPs池。（摘要截断于250字）
