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β-Endorphin as a potent analgesic by intravenous injection


AN untriakontapeptide1 with significant opiate activity from camel pituitary glands was shown to have an amino acid sequence identical to the carboxyl-terminal 31 amino acids of β-lipotropins2,3. The peptide, designated as β-endorphin, has recently been synthesised4, and when administered directly into the brain, it was found5 to be considerably more potent than morphine in molar basis, and its actions were blocked by naloxone. Other peptides related to β-lipotropins have also been shown to possess in vitro opiate-like activity6–9. We report here the analgesic effects of β-endorphin when it is injected intravenously.

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TSENG, LF., LOH, H. & LI, C. β-Endorphin as a potent analgesic by intravenous injection. Nature 263, 239–240 (1976).

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