Blunted adrenocorticotropin and increased adrenal steroid response to human corticotropin-releasing hormone in Alzheimer's disease

Abstract

Previous studies suggest disturbances in the central regulation of the hypothalamic-pituitary-adrenocortical axis (HPA) in advanced Alzheimer's disease (AD). In this study the reactivity of the HPA axis was evaluated by stimulation with corticotropin-releasing hormone (CRH) of patients with mild to moderate AD. Twenty-three patients with AD (aged 61-88 yr) and 19 healthy elderly (aged 62-84 yr) received an intravenous bolus injection of human CRH (1 microgram/kg) at 3:00 PM. CRH-stimulated plasma ACTH levels were significantly lower in AD patients, while serum cortisol, dehydroepiandrosterone, and androstenedione responses relative to the amount of ACTH released were higher in AD patients. Significant correlations were found between low basal plasma ACTH levels and temporal lobe atrophy (p=0.02) and between peak plasma ACTH levels and hippocampal atrophy (p = 0.01). These findings suggest abnormalities at several levels of HPA axis in AD.