Escherichia coli heat-stable toxin receptors in human colonic tumors

摘要: Abstract Background/Aims: Escherichia coli heat-stable enterotoxins (ST) are small peptides of 18 or 19 amino acids that bind to specific cell surface receptors located on the intestinal brush border and activate guanylate cyclase, resulting in an increase intracellular cyclic guanosine 3′,5′-monophosphate content cell. The present study examined whether for ST expressed by primary metastatic human colonic tumors vivo. Methods: Plasma membranes prepared from surgical tissue samples normal colon, liver lung, adenocarcinomas, colon carcinomas lung were analyzed structural functional characteristics constituent receptors. Results: All bound ST, showing high (pmol/L) low (nmol/L) affinity with densities similar those colon. Also, cross-linking labeled showed binding proteins affinity-labeled not detected extraintestinal tissues. Guanylate cyclase was activated all studied, efficacies potencies did this enzyme Conclusions: Receptors vivo,