Immunohistochemical evidence that most rat corticotrophs contain beta-adrenergic receptors

Cells bearing beta-adrenergic receptors (beta-AdRs) were found in the anterior lobe of the rat pituitary gland using antiserum generated against affinity-purified beta 2-AdRs, which also cross-reacts with beta 1-AdRs. beta-AdR-positive cells were sparsely distributed in the anterior pituitary gland. The ultrastructure of these cells was similar to that of corticotrophs. Subsequent analysis of adjacent serial sections indicated that 75% of the ACTH-positive cells were beta-AdR-positive. Our findings demonstrate the presence of beta-AdRs on pituitary corticotrophs, which provides an anatomical basis for the direct regulation of corticotroph secretions by beta-adrenergic agents.