PINEAL CONTROL OF AGING - EFFECT OF MELATONIN AND PINEAL GRAFTING ON AGING MICE

Dark-cycle, night administration of the pineal hormone melatonin in dr inking water to aging mice (15 months of age) prolongs survival of BAL B/c females from 23.8 to 28.1 months and preserves aspects of their yo uthful state. Similar results were seen in New Zealand Black females b eginning at 5 months and C57BL/6 males beginning at 19 months. As mela tonin is produced in circadian fashion from the pineal, we grafted pin eals from young 3- to 4-month-old donors into the thymus of 20-month o ld syngeneic C57BL/6 male recipients, and a 12% increase in survival w as induced. Prolongation of survival was also seen on pineal transplan t to the thymus in C57BL/6, BALB/cJ, and hybrid female mice at 16, 19, and 22 months. In all studies, the endogenous pineal of grafted mice was left in situ. Pineal grafted aged mice display a remarkable mainte nance of thymic structure and cellularity. Preservation of T-cell-medi ated function, despite age, as measured by response to oxazolone is se en. Other evidence suggests that melatonin and/or pineal-related facto rs could produce their effects through an influence on thyroid functio n. These data indicate that pineal influences have a place in the phys iologic regulation of aging.