A somatostatin-secreting cell line established from a human pancreatic islet cell carcinoma (somatostatinoma): release experiment and immunohistochemical study.

Production and secretion of somatostatin (SRIF) were studied using a carcinoembryonic antigen (CEA)-producing cell line (QGP-1) established from a human pancreatic islet cell carcinoma. High concentrations of SRIF (274 +/- 51 ng/mg of protein, mean +/- SD, n = 5) and CEA (3083 +/- 347 ng/mg of protein, mean +/- SD, n = 5) were present in QGP-1 cells, and the basal secretion rates of SRIF and CEA by the cells (n = 5) were 46.4 +/- 4.8 and 1690 +/- 78 pg/10(5) cells/h, respectively. Immunohistochemical studies revealed the presence of SRIF in xenografts of QGP-1 cells and colocalization of SRIF and CEA. Secretion of SRIF by QGP-1 cells was stimulated in the presence of high K+ (50 mmol) and theophylline (10 mmol), but arginine (10 mmol) and glucose (300 mg/dl) had no effect on the SRIF secretion. The QGP-1 cell line may be useful for studying the regulation mechanism of SRIF secretion.