Fine structural effects of hypophysectomy on the aging rat pineal gland

A study was undertaken to examine the effects of pituitary removal on age-related changes in the female rat pineal. Three 9-month-old controls, three 23-month-old controls and three rats hypophysectomized at 19 months and sacrificed at 23 months of age were utilized. Electron microscopic evaluation indicated that following hypophysectomy there was a significant loss of lipid droplets, no change in the frequency of light and dark pinealocytes or cytoplasmic dense bodies (probably lipofuscin), a trend towards increased granular deposits between cells, no change in the number of pinealocytes with nuclear invaginations and decreased numbers of cells with nuclear inclusions. The results indicate that while some tissues (kidney) may show reduced aging indices following hypophysectomy other tissues such as the pineal may be detrimentally affected.