Increased growth and elevated IGF-1 serum concentrations in mice with an adipose tissue specific deletion of the Igf-1 receptor

Insulin-like growth factor-1 (IGF-1) and the IGF-1 receptor have been implicated in the regulation of adipocyte differentiation and lipid accumulation in vitro. To investigate the role of IGF-1 receptor in vivo, we created mice with fat-specific disruption of the IGF-1 receptor gene (FIGF-1RKO mice) using the Cre-loxP system. FIGF-1RKO mice have remarkably increased somatic growth most likely as a consequence of elevated IGF-1 serum concentrations. Higher circulating IGF-1 levels could be due to increased IGF-1 expression both in liver and epigonadal adipose tissue, suggesting that adipose tissue plays a role in…