Given that islet vasculature has been postulated to impact adult islet function (Brissova et al., 2014; Brissova et al., 2006; Cai et al., 2012), we next asked if early developmental phenotypes in VEGF-A expression and islet hyper-vascularization in Adrb2 cKO mice are causal for the later glucose intolerance and insulin secretion defects. Here, INS is linked to Glucose intolerance.