Pituitary removal in adult mice increases life span

Dwarf mutations reduce levels of pituitary hormones and increase life span in mice. But because these dwarf mutations confer life-long hormone deficits that alter development and dramatically reduce fecundity, the relevance of these models to normal aging has been questioned. We examined effects of pituitary hormone withdrawal at different ages using hypophysectomy (surgical removal of the pituitary). Hypophysectomy at 1 month of age extended life span significantly (15%), but hypophysectomy at 9 months of age extended life span to the greatest magnitude (21%) of any age we tested. These results demonstrate pituitary hormone withdrawal can extend life span even if these hormones are removed relatively late in life.