ENSA is an endogenous ligand for sulfonylurea receptor. ENSA reduces K(ATP) channel currents by inhibiting sulfonylurea from binding to the receptor and thus stimulates insulin secretion. Endosulfine Alpha is part of a conserved cAMP-regulated phosphoprotein (ARPP) family. Endosulfine Alpha is an endogenous ligand for the sulfonylurea receptor, ABCC8/SUR1. Endosulfine Alpha is an endogenous regulator of KATP channels. ENSA modulates insulin secretion through the interaction with KATP channel. ENSA is a candidate gene for type 2 diabetes. ENSA is expressed in a wide range of tissues including muscle, brain, and endocrine tissues.