The CgA([left arrow]301) assay (using antibody 871w-1) is specific for the amidated C-terminus of pancreastatin (16).
In a similar study, plasma CgA was quantified with an RIA using an antiserum raised against C-terminal CgA fragments isolated from urine from a carcinoid tumor patient and a pancreastatin antiserum, respectively, and increased concentrations were measured in 99% with the CgA assay and in 46% with the pancreastatin assay (32).
The primary structure of human chromogranin A and pancreastatin.
Characterization of immunoreactive pancreastatin in porcine tissues.
Immunoreactive pancreastatin [CgA(273-301) amide] was measured by RIA using antiserum 871w-1, specific for the amidated COON terminus of pancreastatin, as detailed elsewhere (21).
Lower concentrations were measured using antisera specific for the N-terminal epitope of CgA and the pancreastatin antiserum.
In agreement with our results, pancreastatin concentrations in extracts of human antral mucosa and pancreas have been reported to range from 0.
In our study, six neuroendocrine tumors expressed 10-fold higher pancreastatin concentrations than those reported previously (31, 39).
In agreement with our results, various proportions of CgA(315-321) and CgA(332-337) immunoreactivity in neuroendocrine tumors as well as molecular heterogeneity of immunoreactive pancreastatin and immunoreactive CgA(315-321) have been reported (31, 35, 39).
Increased plasma concentrations of pancreastatin have been described previously in metastatic carcinoid tumors patients (39, 44).