The mineralocorticoid receptor  is a receptor with high affinity for mineralocorticoids. It belongs to the steroid hormone receptor family where the ligand diffuses into cells, interacts with the receptor and results in a signal transduction affecting specific gene expression in the nucleus. The gene for the NR3C2 encodes for the 107 kDa MR protein. MR is expressed in many tissues, such as the kidney, colon, heart, central nervous system (hippocampus), brown adipose tissue and sweat glands. In epithelial tissues, its activation leads to the expression of proteins regulating ionic and water transports resulting in the reabsoprtion of sodium, and as a consequence an increase in extracellular volume, increase in blood pressure, and an excretion of potassium to maintain a normal salt concentration in the body.