By using a radioimmunoassay specific for α-N-acetyl β-endorphin and its C-terminally shortened forms, we have established the presence of immunoreactive α-N-acetyl endorphin (irNacEP) in extracts of five postmortem human pituitary glands (2.27 ± 0.64 ng/gland). This immunoreactivity has been further characterized by subjecting these extracts to reverse-phase high-performance liquid chromatography (RP-HPLC). In all cases the major peaks of irNacEP co-migrated with synthetic human standard α-N-acetyl α-endorphin (NacαEP), α-N-acetyl γ-endorphin (NacγEP) and NacβEP. These studies thus represent the initial demonstration that α-N-acetylation of β-endorphin and its shorter molecular forms occurs in the human pituitary gland.
- Human pituitary
- Reverse-phase HPLC