Nampt (PBEF/Visfatin) as a regulator of cell survival, metabolism and longevity. In this model, Nampt is upregulated by nutrient deprivation, caloric restriction (CR) and other forms of mild stress, and localizes with Nmnat to various organelles to catalyze NAM depletion and NAD+ production. This stimulates sirtuins, PARP and other NAD+ dependent enzymes that boost cell survival and alter metabolism to promote the survival of mammals during adversity. Nampt is also secreted from adipocytes as Visfatin and it bind to the insulin receptor to trigger glucose uptake by peripheral tissues. Prolonged upregulation of Nampt might mimic aspects of CR and extend mammalian lifespan, as PNC1 does in S. cerevisiae.