Research Paper Volume 4, Issue 9 pp 580—589
Low circulating IGF-I bioactivity is associated with human longevity: Findings in centenarians’ offspring
Figure 2. Hypothetical relationships between caloric restriction, the mTOR pathway, insulin and IGF-I receptor sensitivity, circulating insulin levels and IGF-I bioactivity. (A) Overnutrition results in an increased activity of the mTOR pathway, which decreases the sensitivity of the insulin and IGF-I receptors. As a consequence there will be relatively high circulating insulin levels and IGF-I bioactivity. (B) Caloric restriction results in a reduced activity of the mTOR pathway, which increases the sensitivity of the insulin and IGF-I receptors. As a consequence there will be relatively low circulating insulin levels and IGF-I bioactivity.