THE MASTOMYS GASTRIC CARCINOID - ASPECTS OF ENTEROCHROMAFFIN-LIKE CELL-FUNCTION

The mastomys rodent exhibits a genetic propensity to develop gastric c arcinoid tumors. Utilizing acid inhibitory pharmacotherapy (histamine- 2 receptor antagonists and proton pump inhibitors), we have demonstrat ed transformation from normal to neoplastic enterochromaffin-like (ECL ) cells in a well-defined fashion over a period of 4 months. In additi on, we have demonstrated inhibition of tumor growth with either somato statin or histamine-1 receptor antagonists (terfenadine and cyprohepta dine). In order to define the regulation of growth and secretion of tr ansformed ECL cells, we developed an isolated pure ECL cell system. EC L cells secrete histamine in response to gastrinergic (gastrin), musca rinic (carbachol), and a-adrenergic (isoproterenol) stimulation. Both cAMP and intracellular calcium-dependent mechanisms are involved in th e process of histamine secretion.