根据总皮质醇和皮质类固醇结合球蛋白计算的游离血浆皮质醇的临床应用。

Clinical use of unbound plasma cortisol as calculated from total cortisol and corticosteroid-binding globulin.

作者信息

Coolens J L, Van Baelen H, Heyns W

出版信息

J Steroid Biochem. 1987 Feb;26(2):197-202. doi: 10.1016/0022-4731(87)90071-9.

Abstract

A method to calculate unbound cortisol from total cortisol (measured by competitive protein binding) and CBG (measured by radial immunodiffusion) based on the binding equilibrium has been evaluated. The calculated results (y) correlate well with those (x) obtained by centrifugal ultrafiltration at 37 degrees C (y = 1.04 x - 2.11 ng/ml; r = 0.975; n = 150). The concentration of CBG is similar in normal men (37.7 +/- 3.5 (SD) micrograms/ml; n = 12) and women (39.5 +/- 3.7 (SD) micrograms/ml; n = 7) and shows no diurnal variation, but marked diurnal variation is observed for total cortisol (193.7 +/- 35.0 (SD) ng/ml at 08.00 h vs 43.2 +/- 23.3 (SD) ng/ml at 22.00 h; n = 19) and particularly for unbound cortisol (16.5 +/- 5.6 (SD) ng/ml at 08.00 h vs 2.3 +/- 1.8 (SD) ng/ml at 22.00 h; n = 19). The concentration of CBG (89.1 +/- 11.2 (SD) micrograms/ml) and of total cortisol (395.6 +/- 103.3 (SD) ng/ml at 08.00 h; 110.3 +/- 16.6 (SD) ng/ml at 22.00 h) are clearly elevated in estrogen treated women (n = 11) but unbound cortisol levels (17.2 +/- 7.7 (SD) ng/ml at 08.00 h; 2.5 +/- 0.5 (SD) ng/ml at 22.00 h) are similar to the control group. The concentration of CBG is significantly decreased in patients with Cushing's syndrome (33.2 +/- 5.6 micrograms/ml; n = 17) and unbound cortisol is relatively more elevated than total cortisol in these patients. In adrenal insufficiently CBG is normal, but total and unbound cortisol are markedly decreased. There is a significant decrease of CBG in hyperthyroidism (35.7 +/- 5.5 micrograms/ml; n = 22), in cirrhosis (32.0 +/- 8.0 micrograms/ml; n = 14) and in renal disease and a significant increase in patients treated with antiepileptic drugs (47.5 +/- 6.3 micrograms/ml; n = 14), but total and unbound cortisol are normal in all these conditions. We conclude that unbound cortisol can be calculated in a simple and reliable way from total cortisol and CBG and permits a better evaluation of adrenal function, particularly in patients with altered CBG concentrations.

摘要

基于结合平衡，一种根据总皮质醇（通过竞争性蛋白结合法测量）和皮质类固醇结合球蛋白（CBG，通过放射免疫扩散法测量）计算游离皮质醇的方法已得到评估。计算结果（y）与在37℃通过离心超滤获得的结果（x）相关性良好（y = 1.04x - 2.11 ng/ml；r = 0.975；n = 150）。正常男性（37.7±3.5（标准差）μg/ml；n = 12）和女性（39.5±3.7（标准差）μg/ml；n = 7）的CBG浓度相似，且无昼夜变化，但总皮质醇存在明显的昼夜变化（08:00时为193.7±35.0（标准差）ng/ml，22:00时为43.2±23.3（标准差）ng/ml；n = 19），特别是游离皮质醇（08:00时为16.5±5.6（标准差）ng/ml，22:00时为2.3±1.8（标准差）ng/ml；n = 19）。接受雌激素治疗的女性（n = 11）中，CBG浓度（89.1±11.2（标准差）μg/ml）和总皮质醇浓度（08:00时为395.6±103.3（标准差）ng/ml；22:00时为110.3±16.6（标准差）ng/ml）明显升高，但游离皮质醇水平（08:00时为17.2±7.7（标准差）ng/ml；22:00时为2.5±0.5（标准差）ng/ml）与对照组相似。库欣综合征患者的CBG浓度显著降低（33.2±5.6μg/ml；n = 17），且这些患者中游离皮质醇相对总皮质醇升高得更多。肾上腺功能不全时CBG正常，但总皮质醇和游离皮质醇均显著降低。甲状腺功能亢进（35.7±5.5μg/ml；n = 22）、肝硬化（32.0±8.0μg/ml；n = 14）、肾脏疾病患者的CBG显著降低，而接受抗癫痫药物治疗的患者CBG显著升高（47.5±6.3μg/ml；n = 14），但在所有这些情况下总皮质醇和游离皮质醇均正常。我们得出结论，游离皮质醇可以通过总皮质醇和CBG以简单可靠的方式计算得出，并且能够更好地评估肾上腺功能，特别是在CBG浓度改变的患者中。