Miell J P, Taylor A M, Zini M, Maheshwari H G, Ross R J, Valcavi R
Department of Medicine, King's College School of Medicine, London, United Kingdom.
J Clin Endocrinol Metab. 1993 Apr;76(4):950-5. doi: 10.1210/jcem.76.4.7682563.
Normal thyroid status is a prerequisite for the normal growth and development of many tissues. The interrelationships between the thyroid and pituitary-GH-insulin-like growth factor (IGF) axes are complex and not yet fully understood. We have studied the effects of hypothyroidism (n = 22) and hyperthyroidism (n = 17) on levels of serum immunoreactive IGF-I and II, IGF-binding proteins (IGFBP-1 and -3), and IGF bioactivity before and during treatment. We have also assessed changes in GH-binding activity (GHBP). Mean immunoreactive (IR) IGF-I levels in the hypothyroid group rose from 106.6 +/- 10.6 micrograms/L at diagnosis to 139.9 +/- 12.7 micrograms/L (P = 0.009) on normalization of thyroid function. In hyperthyroidism, mean IGF-I levels (258.9 +/- 33.9 micrograms/L) were high initially and fell to 188.7 +/- 14.8 micrograms/L (P = 0.04) after treatment. IR IGF-I levels correlated positively with free T3 and free T4 and negatively with TSH levels. Mean serum IGF-II levels were low in hypothyroid patients (375.2 +/- 37.3) and rose during treatment (516.9 +/- 59.4 micrograms/L; P = 0.04). In the hyperthyroid subjects, however, there was no significant change during therapy (625.0 +/- 66.9 vs. 621.9 +/- 120.8 micrograms/L; P = 0.98). IGF bioactivity potency ratios were low in the hypothyroid group (0.26 +/- 0.03 U/mL) and rose to 0.71 +/- 0.10 U/mL (P = 0.01) during treatment. IGF bioactivity in the hyperthyroid group was also low (0.38 +/- 0.05 U/mL) and rose significantly during treatment (0.81 +/- 0.06 U/mL; P = 0.003). Mean IGFBP-1 levels (29.8 +/- 5.7 micrograms/L) were unaltered by treatment of hypothyroid subjects (28.4 +/- 4.8 micrograms/L). In contrast, IGFBP-1 levels in the hyperthyroid subjects were high at diagnosis (134.6 +/- 26.6 micrograms/L) and fell significantly (71.3 +/- 14.3 micrograms/L; P = 0.04) during treatment. In the hypothyroid group, IGFBP-3 levels rose from an initial mean of 1.98 +/- 0.17 to 2.67 +/- 0.27 mg/L (P = 0.04) during treatment. The higher mean pretreatment levels in the thyrotoxic group (3.46 +/- 0.32 mg/L) were unaltered by treatment (3.20 +/- 0.51 mg/L; P = 0.71). GHBP was low in the hypothyroid group at diagnosis (28.5 +/- 2.5%) and rose during treatment to 40.6 +/- 3.9% (P = 0.02). We have confirmed that IR IGF-I levels are low in hypothyroidism and have demonstrated a reduction in IGF bioactivity and IGF-II and IGFBP-3 levels, and low GH-binding activity, which may reflect a reduction in the processing of GH receptors.(ABSTRACT TRUNCATED AT 400 WORDS)
正常的甲状腺状态是许多组织正常生长和发育的前提条件。甲状腺与垂体 - 生长激素 - 胰岛素样生长因子（IGF）轴之间的相互关系复杂，尚未完全明确。我们研究了甲状腺功能减退（n = 22）和甲状腺功能亢进（n = 17）对治疗前及治疗期间血清免疫反应性IGF - I和II、IGF结合蛋白（IGFBP - 1和 - 3）水平以及IGF生物活性的影响。我们还评估了生长激素结合活性（GHBP）的变化。甲状腺功能减退组的平均免疫反应性（IR）IGF - I水平在诊断时为106.6±10.6μg/L，甲状腺功能正常化后升至139.9±12.7μg/L（P = 0.009）。在甲状腺功能亢进症中，平均IGF - I水平（258.9±33.9μg/L）最初较高，治疗后降至188.7±14.8μg/L（P = 0.04）。IR IGF - I水平与游离T3和游离T4呈正相关，与TSH水平呈负相关。甲状腺功能减退患者的平均血清IGF - II水平较低（375.2±37.3），治疗期间升高（516.9±59.4μg/L；P = 0.04）。然而，在甲状腺功能亢进症患者中，治疗期间无显著变化（625.0±66.9对621.9±120.8μg/L；P = 0.98）。甲状腺功能减退组中IGF生物活性效价比较低（0.26±0.03 U/mL），治疗期间升至0.71±0.10 U/mL（P = 0.01）。甲状腺功能亢进组中的IGF生物活性也较低（0.38±0.
