Extrahypothalamic corticotropin and alpha-melanotropin in human brain

The distribution of corticotropin (ACTH) and alpha-melanotropin (alpha-MSH) in human brain was investigated by radioimmunoassay using an antiserum which recognized h-ACTH1-39 and alpha-MSH to an equal degree on a molar basis. Significant amounts of material, which migrated on calibrated Sephadex G-50 columns as synthetic h-ACTH1-39 and synthetic alpha-MSH, were detected in distinct brain areas. The highest concentrations of ACTH and alpha-MSH were found in the diencephalon (hypothalamus 4.2 and 12.5 pmol/g wet weight, respectively) and in midbrain (periaqueductal gray 0.5 and 1.7 pmol/g, respectively) and smaller quantities in the rhombencephalon and telencephalon. The ACTH concentration in human pituitary (adenohypophysis) was 10(4)-fold greater than that in the hypothalamus. alpha-MSH was confined to the midpart and/or stalk region of the pituitary.