Piragliatin, also known as RO4389620, is a glucokinase activator. Piragliatin greatly enhances glucose-induced pancreatic islet respiration and insulin release. Piragliatin lowers plasma glucose both in the postabsorptive state and after a glucose challenge in patients with type 2 diabetes mellitus. Piragliatin has an acute glucose-lowering action in patients with mild type 2 diabetes, mainly mediated through a generalized enhancement of β-cell function and through fasting restricted changes in glucose turnover.