Vogeser Michael, Briegel Josef
Institute of Clinical Chemistry, Hospital of the University of Munich, Munich, Germany.
Clin Biochem. 2007 Jun;40(9-10):724-7. doi: 10.1016/j.clinbiochem.2007.01.025. Epub 2007 Mar 12.
Biological effects of cortisol are substantially determined by protein binding of the hormone. The aim of our study was to characterize temperature effects on cortisol protein binding by use of an equilibrium dialysis method.
Serum samples obtained from ten healthy volunteers were submitted to equilibrium dialysis. Each sample from the individuals was incubated for 16 h at 37 degrees C, 38 degrees C, 39 degrees C, 40 degrees C and 41 degrees C, respectively. In the dialysate samples obtained, cortisol concentrations were measured by immunoassay.
For samples incubated at 37 degrees C, a mean dialysate cortisol concentration of 0.41 microg/dL (SD=0.14) was found. Gradual increase of dialysate cortisol concentration was observed with increasing incubation temperatures. For samples incubated at 41 degrees C, a mean dialysate cortisol of 0.75 microg/dL (SD=0.24) was found. Thus, the mean percentage of free-to-total cortisol increased by about 80% from 3.7% (SD=1.1) at 37 degrees C to 6.7% (SD=1.8) at 41 degrees C.
The results of our in vitro experiments suggest that during fever the free-to-total ratio of cortisol is increased substantially compared to normal conditions, and that administration of antipyretic drugs might potentially be associated with substantial changes in the bioavailability of cortisol.
皮质醇的生物学效应很大程度上取决于该激素与蛋白质的结合。我们研究的目的是利用平衡透析法来描述温度对皮质醇与蛋白质结合的影响。
从10名健康志愿者身上采集血清样本并进行平衡透析。来自每位个体的每个样本分别在37℃、38℃、39℃、40℃和41℃下孵育16小时。在获得的透析液样本中，通过免疫测定法测量皮质醇浓度。
对于在37℃下孵育的样本，测得透析液皮质醇平均浓度为0.41微克/分升（标准差=0.14）。随着孵育温度升高，观察到透析液皮质醇浓度逐渐增加。对于在41℃下孵育的样本，测得透析液皮质醇平均浓度为0.75微克/分升（标准差=0.24）。因此，游离皮质醇与总皮质醇的平均百分比从37℃时的3.7%（标准差=1.1）增加到41℃时的6.7%（标准差=1.8），增加了约80%。
我们的体外实验结果表明，与正常情况相比，发热期间皮质醇的游离与总比值大幅增加，并且使用退烧药可能会使皮质醇的生物利用度发生显著变化。
