Decreased peripheral glucocorticoid sensitivity in Alzheimer's disease.

Both peripheral and central glucocorticoid sensitivity was examined in patients with Alzheimer's disease (AD; n = 13), glucocorticoid-treated patients (n = 8), healthy elderly controls (n = 10) and young controls (n = 9). We performed glucocorticoid receptor-mediated skin vasoconstrictor responses to clobetasol and low-dose dexamethasone suppression tests. Patients with AD showed skin blanching at a significantly higher clobetasol concentration than did healthy elderly controls (p = 0.002). There was no difference in skin blanching between patients with AD and patients treated with corticosteroids. Patients with AD had significantly higher post-dexamethasone serum cortisol levels than healthy elderly (p = 0.01). No association was found between skin blanching and dexamethasone suppressibility. Thus patients with AD have apparently independent reductions in both central nervous system and peripheral glucocorticoid sensitivity. These results predict an increase in glucocorticoid secretion in some patients, which might accelerate neuronal degeneration in the absence of features of overexposure to glucocorticoids in peripheral tissues.