Each hormone's shape is specific and can be recognized by the corresponding target cells. The binding sites on the target cells are called hormone receptors . Many hormones come in antagonistic pairs that have opposite effects on the target organs. For example, insulin and glucagon have opposite effects on the liver's control of blood sugar level. Insulin lowers the blood sugar level by instructing the liver to take glucose out of circulation and store it, while glucagon instructs the liver to release some of its stored supply to raise the blood sugar level.
Much hormonal regulation depends on feedback loops to maintain balance and homeostasis.
These are classified by chemical structure, not function. Together, they control many other endocrine functions. There are a number of other hypothalamus and pituitary hormones which affect various target organs. This hormone helps prevent excess water excretion by the kidneys. Ethanol inhibits the release of ADH and can, thus, cause excessive water loss.