It has been known that adrenal corticoid is secreted markedly in neurodegenerative disease including Alzheimers disease during aging.The cause of this phenomenon is still unclear.Since Alzheimers disease is considered to be subjected to oxidative stress,H-P-A axis may be damaged by reactive oxygen species (ROS) generated by oxidative stress,and hence,corticoids may secrete abnormally due to a deterioration of a feedback control.