低渗透压反应液促进甲状腺细胞合成cAMP机理

Mechanisms of promoting the synthesis of cAMP in thyroid cells by using hypotonis assay solution

应用ＦＲＴＬ－５大鼠甲状腺细胞研究了无氯化钠低渗透压反应液促进促甲状腺激素（ＴＳＨ）刺激的甲状腺细胞合成环磷酸腺苷（ｃＡＭＰ）的机理。结果：无氯化钠低渗液组细胞内和细胞外液ｃＡＭＰ浓度均高于含氯化钠等渗液组。无氯化钠低渗液组细胞外液ｃＡＭＰ与总ｃＡＭＰ比率高于对照组。低渗液组细胞内和细胞外液ｃＡＭＰ浓度随反应时间延长持续升高；等渗组细胞内ｃＡＭＰ浓度在反应１０ｍｉｎ后达最高水平，以后无增加。结果表明，无氯化钠低渗反应液可能对提高甲状腺细胞膜ｃＡＭＰ的通透性，增强ＴＳＨ受体后反应有一定作用。

Mechanisms of promoting the synthesis of cAMP in thyroid cells by hypotonic assay solution (NaCl-deprived) were studied with FRTL-5 thyroid cells,The intracellular and extracellular cAMP contents after stimulation with TSH were measured with both hypotonic and isotonic assay solution.In the hypotonic group the extracellular and intracellular cAMP concentrations were higher than those in the isotonic group.The ratio between the extracellular cAMP and the total cAMP in the hypotonic group was higher than that in the control.In the hypotonic group, the concentrations of the intracellular and extracellular cAMP increased steadily with the prolongation of reaction time. Under isotonic condition,the intracellular cAMP concentration reached its peak in 10 minutes,whereas it increased progressively under hypotonic condition. Therefore hapotonic assay condition increases the cAMP permeability of the thyroid cell membrance and the postreceptor reaction of TSH.