G-protein-coupled receptor GPR21 knockout mice display improved glucose tolerance and increased insulin response

► GPR21 knockout mice are resistant to diet-induced obesity. ► GPR21 knockout mice have improved glucose tolerance. ► GPR21 knockout mice have increased insulin sensitivity. ► GPR21 knockout mice have increased ambulatory activity. ► Serum inflammatory markers such as MCP-1, SAP, CRP and IP-10 are reduced in GPR21 knockout mice.