Age-dependent increase of clusterin in the human pituitary gland.

Clusterin is a glycoprotein known to play various physiological roles including complement activity, amyloid binding activity in Alzheimer disease, as well as binding with heat shock proteins and abnormal prions. The present study immunohistochemically investigated the expression of clusterin in the human pituitary gland in subjects of 10-88 years of age (n=173). Causes of death were blunt injury (n=35), sharp injury (n=15), poisoning (n=11), drowning (n=14), fire fatalities (n=28), asphyxiation (n=15), hypothermia (n=7), hyperthermia (n=3), and natural diseases (n=45). Clusterin was detected in mixed cell follicles and the anterior lobar parenchymal cells. The area occupied by cells positive for clusterin were measured, and the ratio to the whole area of the anterior lobe (% clusterin-positive cell area) was estimated. There was a good correlation between the age of the subjects in years and the % clusterin-positive cell area in the anterior lobe of the pituitary gland (r=0.736, P<0.01). Relationships between % clusterin-positive cell and gender, cause of death, and survival time were insignificant. These findings indicate an age-dependent accumulation of clusterin in the pituitary gland, which may be related to the aging of endocrine systems.