text: A<unk>  is a specific type of receptor antagonist which blocks the receptor sites for<unk><unk>  hormone (also known as<unk><unk>  factor (CRF)).
  There are four subtypes of this receptor known at present, defined as CRF-1, CRF-2a, CRF-2b and CRF-2g. Three of these receptors are expressed only in the brain, CRF-1 in the cortex and cerebrum, CRF-2a in the lateral septum and hypothalamus and CRF-2g in the amygdala. CRF-2b is expressed in the choroid plexus and cerebral arterioles in the brain, but is mainly expressed peripherally, on the heart and skeletal muscle tissue.
  The main research into CRF antagonists to date has focused on antagonists selective for the CRF-1 subtype. Several antagonists for this receptor have been developed and are widely used in research, with the best-known agents being the selective CRF-1 antagonist antalarmin and a newer drug pexacerfont, although several other ligands for this receptor are used in research, such as LWH-234, CP-154,526, NBI-27914 and R-121,919. Antagonists acting at CRF-2 have also been developed, such as the peptide Astressin-B, but so far no highly selective agents for the different CRF-2 subtypes are available.
option_0: Corticotropin releasing hormone antagonist
option_1: Gonadotropin-releasing hormone antagonist
option_2: Dopamine agonist
option_3: Gonadotropin-releasing hormone agonist
option_4: Dopamine antagonist
option_5: Aldosterone antagonist
option_6: Adrenergic agonist
option_7: Serotonin antagonist