Anti Diuretic Hormone
Antidiuretic hormone (ADH), otherwise known as vasopressin, is a peptide hormone that is used to retain water in the body. This occurs via a pathway resulting in increased cAMP, which allows the insertion of Aquaporin 2 channels into the apical membrane of the distal convoluted tubule in nephrons, which are the functional units in kidneys. These channels allow water to follow it's osmotic gradient and be reabsorbed back into the bloodstream, therefore resulting in a more concentrated urine. This process occurs naturally under physiological circumstances of dehydration because water is vital for the body to function, hence excreting water when the body is in need, could be detrimental to health. ADH is produced in the magnocellular neurones of the hypothalamus and is then stored in the posterior pituitary gland.