Somatostatin-like peptides alter calcium but not secretin sensitivity of gastrinoma cells.

The provocation of gastrin release by calcium or secretin is accepted as a method to differentiate the hypergastrinemia of the Zollinger-Ellison syndrome from that of other causes. We have previously shown that calcium and secretin failed to provoke gastrin release from acutely dispersed gastrinoma cells. This disparity between the in vivo and in vitro effects of these two provocative agents suggests that intermediates may be necessary for calcium- or secretin-induced gastrin release.

The response of a non-functional VIP- and somatostatin-containing tumour to tolbutamide in vitro.

A patient with a tumour containing clinically non-expressive somatostatin (SRIF) and vasoactive intestinal peptide (VIP) was studied in vivo with basal and tolbutamide-provoked SRIF and VIP measurements and failed to respond to tolbutamide infusion. An acute cell dispersion model was used to study this tumour after resection. Incubation of tumour cells in tolbutamide (2 mg/ml) resulted in increases in intracellular SRIF but not in the levels of SRIF released into the incubating medium.

Identification of gastrin-producing cells in cell cultures and smears: an avidin-biotin-peroxidase complex (ABC) technique.

A method is described that uses the avidin-biotin complex (ABC) immunoperoxidase technique to provide a rapid, sensitive, and specific means to quantitate isolated G cells in cultures and suspensions.