Rat pancreas contains the proglucagon(64–69) fragment and arginine stimulates its release

Abstract
Rat proglucagon(64–69) corresponding to the C‐terminal hexapeptide of putative rat glicentin sequence in the precursor was synthesized. A glicentin C‐terminal hexapeptide specific radioimmunoassay, using the synthetic hexapeptide as standard, demonstrated the presence in rat pancreas of a peptide identified with the synthetic rat proglucagon(64–69): H‐Asn‐Arg‐Asn‐Asn‐Ile‐Ala‐OH. The hexapeptide was released concomitantly with glucagon by arginine stimulation from the isolated perfused rat pancreas. The results indicate that the pancreas co‐stores and possibly co‐releases the hexapeptide with glucagon as one of the processing products of proglucagon.