insulin is stored in the liver of the human body.
insulin is stored in the liver of the human body.
where is insulin stored in the human body?
liver
insulin is released from the pancreas and into the bloodstream in response to increased glucose concentration in the blood. insulin is stored in beta cells in the pancreas. when glucose in the blood binds to glucose receptors on the beta cell membrane, a signal cascade is initiated inside the cell that results in insulin stored in vesicles in these cells being released into the blood stream. increased insulin levels cause the uptake of glucose into the cells. glut4 is stored in the cell in transport vesicles, and is quickly incorporated into the plasma membrane of the cell when insulin binds to membrane receptors.
glut4
glucose enters the beta cells and goes through glycolysis to form atp that eventually causes depolarization of the beta cell membrane (as explained in insulin secretion section of this article). the depolarization process causes voltage-controlled calcium channels (ca2+) opening, allowing the calcium to flow into the cells. an increased calcium level activates phospholipase c, which cleaves the membrane phospholipid phosphtidylinositol 4,5-bisphosphate into inositol 1,4,5-trisphosphate (ip3) and diacylglycerol (dag). ip3 binds to receptor proteins in the membrane of endplasmic reticulum (er). this releases (ca2+) from the er via ip3 gated channels, and raises the cell concentration of calcium even more. the influx of ca2+ ions causes the secretion of insulin stored in vesicles through the cell membrane. the process of insulin secretion is an example of a trigger mechanism in a signal transduction pathway, because insulin is secreted after glucose enters the beta cell and that triggers several other processes in a chain reaction.
insulin signal transduction pathway