Mc. Woussencolle et al., CHROMOGRANIN A(210-301) IS THE MAJOR FORM OF PANCREASTATIN-LIKE MATERIAL IN HUMAN GUT EXTRACTS AND ENDOCRINE TUMORS, Peptides, 15(5), 1994, pp. 869-874
A radioimmunoassay of human pancreastatin was developed using a rabbit
antiserum that selectively recognized the C-terminal amidated end of
the peptide, and it was used for the identification of the molecular f
orms of pancreastatin in human gut (stomach, duodenum, small intestine
, colon) and endocrine tumor extracts (liver metastasis of a gastrinom
a and a medullary carcinoma of thyroid, one nonsecreting pancreatic tu
mor, one recurrence of a gut carcinoid, one vipoma and one insulinoma)
. In all gut extracts, a gel filtration chromatography revealed the pr
esence of three peaks of pancreastatin-like immunoreactivity. The pred
ominant form eluted with an apparent molecular weight higher than that
of pancreastatin. This form was also predominant in the endocrine tum
ors analyzed, except in the insulinoma, where a lower molecular weight
form predominated. The high molecular form was further purified from
a liver metastasis of a gastrinoma. The pancreastatin-like immunoreact
ivity eluted in all the chromatographical systems (reverse-phase, ion
exchange) as a single peak that was finally purified to homogeneity an
d sequenced. The sequence of the first 29 N-terminal amino acids was o
btained unambiguously and corresponded to the sequence 210-238 of chro
mogranin A. Considering the selectivity of the assay used for peptide
identification, this major form was identified as the fragment 210-301
of chromogranin A, It is likely that the predominant form of pancreas
tatin in human gut extracts and noninsular tumors is a 92 amino acid p
eptide.