A cell is able to respond to a hormone with the help of a specific hormone receptor. A hormone receptor is a molecule the binds to a specific hormone. Some of the major hormone receptors are: peptide receptor, steroid receptor, insulin receptor, glucagon receptor and others. Hormones circulate mostly in blood and in extracellular fluid, coming into contact with most cells.Hormones control essential body functions by carrying messages from the endocrine systems to target cells and tissues.