title: Control of ion transport in mouse proximal and distal colon by prolactin.
abstract: The lactogenic hormone prolactin (PRL) has been known to affect Ca(2+) and electrolyte transport in the intestinal epithelium. In the present study we analyzed ion transport in mouse proximal and distal colon, and acute changes induced by PRL. In the proximal colon, carbachol activated a Ca(2+) dependent Cl(-) secretion that was sensitive to DIDS and NFA. In the distal colon, both ATP and carbachol activated K(+) secretion. Ca(2+) -activated KCl transport in proximal and distal colon was inhibited by PRL (200 ng/ml), while amiloride sensitive Na(+) absorption and cAMP induced Cl(-) secretion remained unaffected. Luminal large conductance Ca(2+) -activated K(+) (BK) channels were largely responsible for Ca(2+) -activated K(+) secretion in the distal colon, and basolateral BK channels supported Ca(2+) -activated Cl(-) secretion in the proximal colon. Ca(2+) chelating by BAPTA-AM attenuated effects of carbachol and abolished effects of PRL. Both inhibition of PI3 kinase with wortmannin and blockage of MAP kinases with SB 203580 or U 0126, interfered with the acute inhibitory effect of PRL on ion transport, while blocking of Jak/Stat kinases with AG 490 was without effects. PRL attenuated the increase in intracellular Ca(2+) that was caused by stimulation of isolated colonic crypts with carbachol. Thus PRL inhibits Ca(2+) dependent Cl(-) and K(+) secretion by interfering with intracellular Ca(2+) signaling and probably by activating PI3 kinase and MAP kinase pathways.
authors.affiliation: Institut für Physiologie, Universität Regensburg, Germany.
authors.forename: Supaporn
authors.initials: S
authors.lastname: Puntheeranurak
authors.forename: Rainer
authors.initials: R
authors.lastname: Schreiber
authors.forename: Melanie
authors.initials: M
authors.lastname: Spitzner
authors.forename: Jiraporn
authors.initials: J
authors.lastname: Ousingsawat
authors.forename: Nateetip
authors.initials: N
authors.lastname: Krishnamra
authors.forename: Karl
authors.initials: K
authors.lastname: Kunzelmann
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002712:Chlorides / Q000378:metabolism; D003106:Colon / Q000187:drug effects* / Q000378:metabolism; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000502:physiology*; D053503:Epithelial Sodium Channels / Q000502:physiology*; D066298:In Vitro Techniques; D017136:Ion Transport / Q000187:drug effects*; D051379:Mice; D008810:Mice, Inbred C57BL; D008954:Models, Biological; D011188:Potassium / Q000378:metabolism; D011388:Prolactin / Q000494:pharmacology*; D015398:Signal Transduction
chemical_list: D002712:Chlorides; D053503:Epithelial Sodium Channels; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D011388:Prolactin; D011188:Potassium; D002118:Calcium