A Cdk5 inhibitor enhances the induction of insulin secretion by exendin-4 both in vitro and in vivo.

Exendin-4 (Ex4) is a peptide found in the lizard Heloderma suspectum, and it has a high similarity to glucagon-like peptide 1 (GLP-1). It induces insulin secretion without the risk of hypoglycemic episodes. Cyclin-dependent kinase 5 (Cdk5) is a serine/threonine kinase that is predominantly expressed in neurons.