Central-type benzodiazepine binding sites in rat pituitary gland are of the BZ1 subtype

Experiments were performed to investigate the subtype of central-type benzodiazepine binding site present in rat pituitary gland. Bmax values for [3H] n-propyl beta-carboline-3-carboxylate and [3H] flunitrazepam (for central-type binding only) were similar. Displacement of [3H] flunitrazepam by n-propyl beta-carboline-3-carboxylate gave a linear Hofstee plot and a Hill coefficient close to unity. These results suggest that the central benzodiazepine binding sites in the pituitary are predominantly of the BZ1 subtype, as found in the cerebellum.