β-Endorphin (rat) (trifluoroacetate salt)

β-Endorphin (β-EP) is an endogenous opioid neuropeptide with diverse biological activities.¹ It is produced via piomelanocortin cleavage in the pituitary gland, hypothalamus, and in lymphocytes, then migrates to its sites of action which include plasma, gut, skin, placenta, cerebrospinal fluid, and cardiac tissues. β-EP induces concentration-dependent decreases in electrically stimulated contraction of the mouse vas deferens that can be reversed by the μ-opioid antagonist CTP and δ-opioid antagonist ICI 174,864.² In vivo, β-EP (5 μg, i.c.v.) slows gastrointestinal transit in mice. β-EP (0.5 or 5 μg, i.c.v.) stimulates food intake in rats for 4 to 6 hours, however, this effect is not prolonged with continuous infusion.³ It antagonizes the appetite-suppressive effects of α-melanocyte-stimulating hormone (α-MSH) for the first three days post administration. β-EP also reduces paralytic demyelination induced by the murine coronavirus MHV-JHM in immunocompetent, but not irradiated or immune-incompetent, mice and rats.⁴

1.Herath, H.M., Cabot, P.J., Shaw, P.N., et al.Study of beta endorphin metabolism in inflamed tissue, serum and trypsin solution by liquid chromatography-tandem mass spectrometric analysisAnal. Bioanal. Chem.402(6)2089-2100(2012) 2.Shook, J.E., Kazmierski, W., Wire, W.S., et al.Opioid receptor selectivity of beta-endorphin in vitro and in vivo: mu, delta and epsilon receptorsJ. Pharmacol. Exp. Ther.246(3)1018-1025(1988) 3.Dutia, R., Meece, K., Dighe, S., et al.β-Endorphin antagonizes the effects of α-MSH on food intake and body weightEndocrinology153(9)4246-4255(2012) 4.Gilmore, W., and Moradzadeh, D.S.b-endorphin protects mice from neurological disease induced by the murine coronavirus MHV-JHMJ. Neuroimmunol.48(1)81-90(1993)