“…Most recently, the I sc response of human intestine to STa was not inhibited by the cyclooxygenase inhibitor indomethacin, suggesting that prostaglandins do not mediate the secretory response to STa (296). In addition, on the basis of inhibitor studies and studies with isolated rat intestinal epithelial cells, a role for phosphatidylinositol and diacylglycerol release with elevation of intracellular calcium levels and activation of PKC has been proposed to be important in STa-stimulated secretion (16,17,60,61,174,191,286,287,530). Although in vitro studies have shown release of these potential secretory mediators, correlation with a secretory response is not yet available.…”