GSK1362885 is a glycogen phosphorylase inhibitor that is targeted as a treatment for Type 2 Diabetes Mellitus by reducing hepatic glucose output. This study will investigate the safety, tolerability, pharmacokinetics, and pharmacodynamics when single doses of GSK1362885 are administered to healthy volunteers. A glucagon challenge test will be used to stimulate hepatic glucose output in order to evaluate liver glycogen phosphorylase inhibition by GSK1362885.