Van Sande J, Ketelbant-Balasse P, Grenier G, Dumont J E
Endocrinology. 1978 Feb;102(2):576-81. doi: 10.1210/endo-102-2-576.
Thyroid metabolism undergoes general activation in the presence of TSH. Secretion, [1-14C]-glucose oxidation, protein iodination, and cyclic AMP (cAMP) accumulation are stimulated. In intact tissue, it is difficult to dissociate effects of cAMP itself and effects secondary to cAMP-induced secretion. We report herein that cooling to 20 C dissociates the action of TSH on secretion from all its other effects. At this temperature, TSH stimulation of secretion was completely inhibited whereas cAMP accumulation was enhanced. The TSH effect on [1-14C]glucose oxidation was maintained and its action on protein iodination was diminished but not abolished. The ATP content was not decreased. The mechanism of action of cooling was investigated. No pseudopod formation of intracellular colloid droplets were observed by scanning electron microscopy and transmission electron microscopy, thus indicating that the inhibition affects the first step of secretion, i.e., colloid phagocytosis. Microtubules were not seen at 2 C but were normally present at 20 C. The data are compatible with the hypothesis that inhibition of phagocytosis at 20 C could be a consequence of a lipid phase transition in the membrane.
在促甲状腺激素（TSH）存在的情况下，甲状腺代谢会发生全面激活。其分泌、[1-14C] - 葡萄糖氧化、蛋白质碘化以及环磷酸腺苷（cAMP）积累都会受到刺激。在完整组织中，很难区分cAMP本身的作用以及cAMP诱导分泌所继发的作用。我们在此报告，冷却至20℃可使TSH对分泌的作用与其所有其他作用相分离。在此温度下，TSH对分泌的刺激作用被完全抑制，而cAMP积累增强。TSH对[1-14C]葡萄糖氧化的作用得以维持，其对蛋白质碘化的作用减弱但未消除。ATP含量未降低。对冷却的作用机制进行了研究。通过扫描电子显微镜和透射电子显微镜均未观察到细胞内胶体小滴形成伪足，因此表明这种抑制作用影响分泌的第一步，即胶体吞噬作用。在2℃时未见到微管，但在20℃时微管正常存在。这些数据与以下假设相符，即在20℃时吞噬作用受到抑制可能是膜中脂质相转变的结果。
