PBR (Peripheral type Benzodiazepine Receptor) is a ubiquitous protein (18 kDa) found in most steroidogenic tissues. It is located primarily in the outer mitochondrial membrane of steroid producing tissues and is found in association with a 34 kDa voltage dependent anion channel protein (VDAC). PBR interacts with some benzodiazepines and has different affinities than its endogenous counterpart. PBR appears to be a key factor in the transport of cholesterol from the outer to the inner mitochond