Abstract: The cystic fibrosis transmembrane conductance regulator CFTR is critical to cAMP and cGMP activated intestinal anion secretion and the pathogenesis of secretory diarrhea. Enterotoxins released by Vibrio Cholera (cholera toxin) and E. Coli (Heat Stable Enterotoxin,STa) activate intracellular cAMP and cGMP and signal CFTR on the apical plasma membrane of small intestinal enterocytes to elicit chloride and fluid secretion. cAMP activates PKA, while cGMP signals a cGMP-dependent protein kinase (cGKII) to phosphorylate CFTR in the intestine. In the jejunum, cAMP also regulates CFTR and fluid secretion by insertion of CFTR from subapical vesicles to the surface of enterocytes. Whether cGMP signaling or phosphorylation regulate the insertion of CFTR associated vesicles from the cytoplasm to the surface of enterocytes is unknown. We used Heat Stable Enterotoxin (STa), cell permeant cGMP and cAMP agonists in conjunction with PKG and PKA inhibitors respectively in rat jejunum to examine whether (1) cGMP and cGK II regulate the translocation of CFTR to the apical membrane and its relevance to fluid secretion (2) PKA regulates cAMP-dependent translocation of CFTR because this intestinal segment is a primary target for toxigenic diarrhea. STa and cGMP induced a greater than 4-fold increase in surface CFTR in enterocytes in association with fluid secretion that was inhibited by PKG inhibitors. cAMP agonists induced a translocation of CFTR to the cell surface of enterocytes that was prevented by PKA inhibitors. We conclude that cAMP and cGMP-dependent phosphorylation regulates fluid secretion and CFTR trafficking to the surface of enterocytes in rat jejunum.