Acetyl β-Endorphin (human) (trifluoroacetate salt)

Acetyl β-endorphin is an acetylated derivative of β-endorphin that binds to opioid receptors in rat caudal dorsomedial medulla (Ki = 490 nM) and mouse brain membrane preparations (IC50 = 109 nM). It induces chemotaxis of human monocytes in vitro when used at a concentration of 0.1 nM. In vivo, it reduces antinociception in mice induced by β-endorphin , morphine, [D-Ala2, N-Me-Phe4, Gly5-ol]-enkephalin , and [D-Ala2, D-Leu5]-enkephalin (DADLE) in a tail-flick test (ED50s = 2.08, 33.11, 0.03, and 0.07 mol per animal, respectively).