ENPP1 and Insulin resistance: The necessity of NPP1 for physiological skeletal mineralization combined with the considerable evidence linking NPP1 expression with insulin resistance (Bacci et al., 2007; Baratta et al., 2008; Chandalia et al., 2012; González-Sánchez et al., 2008; Harmey et al., 2004) led us to investigate whether NPP1 has a functional role in bone as a newly identified regulator of energy metabolism.