IGF1R and hyperinsulinism: Constitutive adipose tissue-specific deletion of IR and IGF1R using an aP2 promoter Cre, and even more so using an adiponectin promoter Cre, leads to a marked lipodystrophy phenotype with almost complete loss of both white and brown adipose tissue accompanied by marked glucose intolerance, fatty liver, hyperlipidemia, hyperinsulinemia with islet hyperplasia and insulin resistance [1,4,14,46].