| Abstract: | Immunoreactive ACTH and β-endorphin (β-End) were localized in the brain and pituitaries of normal and colchicine-treated rats, using the immunoperoxidase method at the light microscopic level. On adjacent serial 5-μm paraffin sections of anterior pituitaries, both ACTH and β-End could be found in the same cells. On adjacent 5-μm paraffin sections of brains of colchicine-treated rats, both ACTH and β-End could be found in the same perikarya of hypothalamic arcuate nucleus neurons. It appeared that all perikarya containing β-End contained ACTH as well, suggesting that neurons producing β-End also produce ACTH. Pathways of ACTH fibers corresponded to pathways of β-End fibers. These findings suggest that the synthesis, and transport, of ACTH and β-End are linked in the brain as well as in the pituitary, possibly through a common precursor. |
