Insulin secretion and functions Secreted from beta-cells in pancreatic islet High glucose level increases intracellular ATP level, which closes ATP-dependent potassium channel, causing depolarization Depolarization of beta-cell opens voltage-gated calcium channel.Ca2+influx increases intracellular Ca2+level. leading to secretion of insulin Insulin promotes synthesis and storage of glycogen, triglycerides and proteins Major target organs are liver,fat tissue and muscleInsulin secretion and functions • Secreted from beta-cells in pancreatic islet • High glucose level increases intracellular ATP level, which closes ATP-dependent potassium channel, causing depolarization • Depolarization of beta-cell opens voltage-gated calcium channel. Ca2+ influx increases intracellular Ca2+ level, leading to secretion of insulin • Insulin promotes synthesis and storage of glycogen, triglycerides and proteins • Major target organs are liver, fat tissue and muscle