Figure 1. The norm and type 2 diabetes (simplified schema).
(A) The norm. Insulin and nutrients such as glucose stimulate mTOR, which blocks insulin signaling (feedback loop).
(B-C) High mTOR/S6K activity: insulin resistance plus decreased lifespan. (B) Overactivated by nutrients, cytokins, insulin and other hormones, mTOR blocks insulin signaling causing insulin resistance. Nutrients overstimulate beta-cells and insulin is increased. (C) In type II diabetes, beta-cells eventually fail and levels of insulin may be decreased.