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Inhibitory effect of thyrotrop in-releasing hormone on pancreatic enzyme secretion
$46
INHIbiTt,RY EFFECT 6.F TItYROTRO~IN-iI~m~i!'~G HOI{MONE ON I~ANCREA']!IC ENZYi
PEPTIDES COMMON TO CARCINOID TUMOUR GRANULES AND ENTEROCHROMAFFIN CELLS R H~kanson, 3 AlumeLs, R Ekman, F Sundler and 3 1Thorell, Departments of Pharmacology, Histology and Nuclear Medicine (in MalmB), University of Lund, Sweden. Midgut carcinoid tumours are thought to arise from enterochromaffin cells; as a rule they contain large amounts of 5-HT. Many such tumours produce substance P in addition to 5-HT. Material from a tumour containing 5-HT and substance P was fractionated to obtain purified secretory granules. Antiserum was raised against the granule fraction. The antiserum, which did not react with 5-HT or substance P, bound to carcinoid tumour cells. Immunoperoxidase staining of ultrathin sections of carcinoid tumour tissue revealed the immunoreactive components to occur exclusively in the secretory granules. In addition, the antiserum stained a population of enterochromaffin cells in normal human intestinal mucosa. In crossed immunoelectrophoresis solubilized granular polypeptides gave at least two anodal precipitates. Furthermore, at least one polypeptide (with a MW below 5000) was revealed by SDS-PAGE and identified by immunoprecipitation following embedding of a SDS-PAGE strip in agarose and allowing the polypeptide to diffuse against the antiserum. Isolation and characterization of the immunoreactive components are in progress.
INHIbiTt,RY EFFECT 6.F TItYROTRO~IN-iI~m~i!'~G HOI{MONE ON I~ANCREA']!IC ENZYi
PEPTIDES COMMON TO CARCINOID TUMOUR GRANULES AND ENTEROCHROMAFFIN CELLS R H~kanson, 3 AlumeLs, R Ekman, F Sundler and 3 1Thorell, Departments of Pharmacology, Histology and Nuclear Medicine (in MalmB), University of Lund, Sweden. Midgut carcinoid tumours are thought to arise from enterochromaffin cells; as a rule they contain large amounts of 5-HT. Many such tumours produce substance P in addition to 5-HT. Material from a tumour containing 5-HT and substance P was fractionated to obtain purified secretory granules. Antiserum was raised against the granule fraction. The antiserum, which did not react with 5-HT or substance P, bound to carcinoid tumour cells. Immunoperoxidase staining of ultrathin sections of carcinoid tumour tissue revealed the immunoreactive components to occur exclusively in the secretory granules. In addition, the antiserum stained a population of enterochromaffin cells in normal human intestinal mucosa. In crossed immunoelectrophoresis solubilized granular polypeptides gave at least two anodal precipitates. Furthermore, at least one polypeptide (with a MW below 5000) was revealed by SDS-PAGE and identified by immunoprecipitation following embedding of a SDS-PAGE strip in agarose and allowing the polypeptide to diffuse against the antiserum. Isolation and characterization of the immunoreactive components are in progress.