Insulin is a peptide hormone secreted by the pancreas and results in the lowering of blood sugar levels.
It acts on liver, fat, muscle and other tissues to stimulate uptake of glucose. Uptaken glucose is either metabolised or converted to glycogen and fat. After a meal, when blood glucose levels rise, insulin is released so that cells can uptake the elevated glucose levels. Glucagon is a peptide hormone that acts upon the liver to stimulate breakdown of glycogen and raise blood sugar levels.