Chatsri DeachapunyaSutthasinee PoonyachotiNateetip KrishnamraSrinakharinwirot UniversityChulalongkorn UniversityMahidol University2018-06-112018-06-112012-05-15American Journal of Physiology - Gastrointestinal and Liver Physiology. Vol.302, No.10 (2012)15221547019318572-s2.0-84861141161https://repository.li.mahidol.ac.th/handle/20.500.14594/13730The effect of prolactin (PRL) on ion transport across the rat colon epithelium was investigated using Ussing chamber technique. PRL (1 μg/ml) induced a sustained decrease in short-circuit current (I sc ) in the distal colon with an EC 50 value of 100 ng/ml and increased I sc in the proximal colon with an EC 50 value of 49 ng/ml. In the distal colon, the PRL-induced decrease in I sc was not affected by Na + channel blocker amiloride or Cl - channel blockers, NPPB, DPC, or DIDS, added mucosally. However, the response was inhibited by mucosal application of K + channel blockers glibenclamide, quinidine, and chromanol 293B, whereas other K + channel blockers, Ba 2+ , tetraethylammonium, clotrimazole, and apamin, failed to have effects. The PRL-induced decrease in I sc was also inhibited by Na + -K + -2Cl - transporter inhibitor bumetanide, Ba 2+ , and chromanol 293B applied serosally. In the transverse and proximal colon, the PRL-induced increase in I sc was suppressed by DPC, glibenclamide, and bumetanide, but not by NPPB, DIDS, or amiloride. The PRL-induced changes in I sc in both distal and proximal colon were abolished by JAK2 inhibitor AG490, but not BAPTA-AM, the Ca 2+ chelating agent, or phosphatidylinositol 3-kinase inhibitor wortmannin. These results suggest a segment-specific effect of PRL in rat colon, by activation of K + secretion in the distal colon and activation of Cl - secretion in the transverse and proximal colon. Both PRL actions are mediated by JAK-STAT-dependent pathway, but not phosphatidylinositol 3-kinase pathway or Ca 2+ mobilization. These findings suggest a role of PRL in the regulation of electrolyte transport in mammalian colon. © 2012 the American Physiological Society.Mahidol UniversityBiochemistry, Genetics and Molecular BiologyMedicineArticleSCOPUS10.1152/ajpgi.00143.2011