Smith P, Williams E D, Wynford-Thomas D
Mol Cell Endocrinol. 1987 May;51(1-2):51-8. doi: 10.1016/0303-7207(87)90118-3.
Sustained elevation of serum thyrotropin (TSH) induces an initial proliferation of rat thyroid follicular cells, leading to goitre formation followed by a 'plateau phase' in which the growth response to TSH is lost. To investigate this growth desensitisation mechanism, we have compared the sensitivity to growth factors of normal and 'plateau phase' rat thyroid epithelium in primary follicle cultures. Insulin at supraphysiological concentrations stimulates growth (DNA synthesis) in both cell types. TSH at a concentration found in 'plateau phase' animals (0.1 mU/ml) is maximally growth stimulatory for normal, but not significantly stimulatory for 'plateau' epithelium. At much higher concentrations however (greater than or equal to mU/ml) an equal response is obtained from both. We conclude that the growth desensitising mechanism is intrinsic to the follicular cell, is at least partly specific to TSH, and is effective only over the range of TSH concentrations found in vivo.
血清促甲状腺激素（TSH）持续升高会诱导大鼠甲状腺滤泡细胞最初增殖，导致甲状腺肿形成，随后进入“平台期”，在此期间对TSH的生长反应丧失。为研究这种生长脱敏机制，我们比较了原代滤泡培养中正常和处于“平台期”的大鼠甲状腺上皮对生长因子的敏感性。超生理浓度的胰岛素可刺激两种细胞类型的生长（DNA合成）。处于“平台期”动物体内发现的浓度（0.1 mU/ml）的TSH对正常细胞具有最大生长刺激作用，但对“平台期”上皮细胞无明显刺激作用。然而，在高得多的浓度下（大于或等于mU/ml），两种细胞获得相同反应。我们得出结论，生长脱敏机制是滤泡细胞固有的，至少部分对TSH具有特异性，并且仅在体内发现的TSH浓度范围内有效。
