alphaendorphin

Alpha-endorphin is an endogenous opioid peptide that belongs to the endorphin family. In mammals it is produced in the brain and pituitary gland as a product of proteolytic processing of the larger precursor proopiomelanocortin (POMC). Like other endorphins, alpha-endorphin is released in response to stress and nociceptive stimuli and is involved in the modulation of pain and the neuroendocrine stress response.

Biochemical and distribution notes indicate that alpha-endorphin is formed from the same POMC precursor that yields beta-endorphin, but it has a distinct amino acid sequence. This difference can influence its receptor-binding properties and the specific brain regions where it is most active. The precise tissue distribution and relative abundance of alpha-endorphin can vary among species and experimental conditions.

Pharmacologically, alpha-endorphin binds to opioid receptors and is believed to contribute to mu-opioid receptor–mediated analgesia and mood regulation. Its in vivo potency and receptor selectivity are less well characterized than those of beta-endorphin, and its effects may depend on context and interacting signaling pathways. Alpha-endorphin can be detected in plasma following physical stress, exercise, or brain injury, reflecting its release during physiological challenges.

Physiological and clinical aspects remain areas of active research. Alpha-endorphin is generally considered less prominent than beta-endorphin in the literature, but it is recognized as part of the broader system of endogenous opioids that modulate pain, stress, and mood.