Pancreas is an endocrine gland. It secretes two types of endocrine hormones, namely insulin and glucagon. Insulin is secreted by the beta cells of the islets of Langerhans of pancreas. Glucagon is secreted by the alpha cells of the islets of Langerhans of pancreas. Insulin decreases the blood glucose level when there is high amount of sugar present in the blood. Glucagon releases glucose from the liver in the blood when there is low levels of sugar present in the blood.