Carson S W, Halbreich U, Yeh C M, Asnis G, Goldstein S
Department of Psychiatry, State University of New York, Buffalo.
Biol Psychiatry. 1988 Sep;24(5):569-77. doi: 10.1016/0006-3223(88)90167-9.
It has been suggested that dexamethasone pharmacokinetics may affect cortisol suppression during the Dexamethasone Suppression Test (DST). In depressed patients the cortisol response has been shown to negatively correlate with dexamethasone plasma concentrations, which also influence the sensitivity and specificity of the DST. These findings have been interpreted as weakening the utility of the DST. However, the analysis of pre- and post-1 mg DST cortisol concentrations corrected for plasma dexamethasone concentrations suggest that compared with normals (n = 52), patients with major depressive disorder (MDD) as a group (n = 71) had less suppressibility of cortisol to the same plasma dexamethasone concentrations. Moreover, when the MDD patients were evaluated based on DST status, the suppressors had cortisol/dexamethasone ratios (micrograms/dl of cortisol per ng/ml of plasma dexamethasone) similar to the normal controls, whereas the nonsuppressors had ratios that were significantly higher. These data suggest that DST non-suppression, as well as sensitivity and specificity of the DST in depression, is not only attributable to altered dexamethasone disposition, but indeed, there is a genuine reduced sensitivity of cortisol to dexamethasone that still points to an abnormality of the delayed feedback mechanism of the hypothalamic-pituitary-adrenal system in some depressed patients.
有人提出，地塞米松的药代动力学可能会影响地塞米松抑制试验（DST）期间的皮质醇抑制情况。在抑郁症患者中，已表明皮质醇反应与地塞米松血浆浓度呈负相关，而这也会影响DST的敏感性和特异性。这些发现被解释为削弱了DST的实用性。然而，对1毫克DST前后的皮质醇浓度进行血浆地塞米松浓度校正后的分析表明，与正常人（n = 52）相比，重度抑郁症（MDD）患者组（n = 71）对相同血浆地塞米松浓度的皮质醇抑制能力较低。此外，当根据DST状态对MDD患者进行评估时，抑制者的皮质醇/地塞米松比率（每纳克/毫升血浆地塞米松对应的微克/分升皮质醇）与正常对照组相似，而非抑制者的比率则显著更高。这些数据表明，DST不抑制以及DST在抑郁症中的敏感性和特异性，不仅归因于地塞米松处置的改变，实际上，确实存在皮质醇对地塞米松的敏感性真正降低的情况，这仍然表明一些抑郁症患者下丘脑 - 垂体 - 肾上腺系统的延迟反馈机制存在异常。
