ENDOCRINE-CELLS WITH GASTRIN CHOLECYSTOKININ-LIKE IMMUNOREACTIVITY INTHE PANCREAS OF THE SPINY DOGFISH, SQUALUS-ACANTHIAS

Endocrine cells containing gastrin/cholecystokinin (CCK)-like immunore activity were localized to the islet tissue in the pancreas of the spi ny dogfish. Most of these cells were located in the 'intestinal' lobe of the pancreas; only occasional cells were observed in the 'splenic' lobe. The gastrin/CCK-like immunoreactive cells were often co-localize d with the 'classical' pancreas hormones (insulin, glucagon and somato statin). Radioimmunoassay of water extracts with a C-terminally direct ed antiserum revealed high levels of immunoreactive material in the in testinal part (48.6 +/- 19.9 pmol/g) and lower levels (4.5 +/- 0.6 pmo l/g) in the splenic part. Acetic acid extracts of the intestinal lobe contained low levels (6.8 +/- 3.3 pmol/g) of gastrin/CCK-like immunore activity, whereas corresponding extracts of the splenic part showed no immunoreactivity. When the extracts were subjected to DEAE ion-exchan ge chromatography the gastrin/CCK-like peptides eluted as a major peak . After Sephadex gel filtration, pooled immunoreactive material from t he main DEAE chromatographic peak eluted at a position close to that o f CCK4. Further characterization by ion-exchange and reversed-phase HP LC showed that, in general, the immunoreactive material behaved like t he shorter forms of the gastrin/CCK family (CCK4/G5 and CCK8/Cae 3-10) .