Perspectives on the Activities of ANGPTL8/Betatrophin

In this issue of Cell, Gusarova et al. (2014) show that deletion of ANGPTL8 in mice does not affect the compensatory proliferation of pancreatic beta cells in response to insulin resistance induced by a high-fat diet or treatment with the insulin antagonist S961. They also show that overexpression of human ANGPTL8 in mouse liver leads to elevated serum triglyceride levels but not significant pancreatic beta cell proliferation. They conclude that ANGPTL8 (also called betatrophin [Yi et al., 2013]/RIFL [Ren et al., 2012]/lipasin [Zhang, 2012]) does not control pancreatic beta cell expansion.