To test our hypotheses, we used a novel mouse model of adult‐onset, isolated endocrine IGF‐1 deficiency induced by adeno‐associated viral knockdown of IGF‐1 specifically in the liver of postpubertal mice using Cre‐lox technology (Igf1f/f + TBG‐Cre‐AAV8) (Toth et al., 2014b). Here, IGF1 is linked to hyperinsulinemic hypoglycemia, familial, 4.