title: Basolateral active uptake of nitrofurantoin in the CIT3 cell culture model of lactation.
abstract: Nitrofurantoin and other agents are actively transported into human and rodent milk. The purpose of this study was to determine whether nitrofurantoin active transport across mammary epithelia occurs basolaterally or apically, using the CIT3 cell culture model of lactation. The CIT3 model actively transports nitrofurantoin in the basolateral to apical direction. Basolateral to apical permeability [92.9 +/- 6.6 (microl/h)/cm(2)] was differentially decreased by unlabeled nitrofurantoin (250 microM) on the basolateral, apical, or both sides [49.5 +/- 1.8, 57.9 +/- 1.4, or 48.5 +/- 1.6 (microl/h)/cm(2), respectively]. Apical to basolateral permeability [27.6 +/- 1.8 (microl/h)/cm(2)] was increased in the presence of unlabeled nitrofurantoin (250 microM) on the basolateral, apical, or both sides [36.4 +/- 1.5, 39.9 +/- 0.7, 42.4 +/- 1.1 (microl/h)/cm(2), respectively]. These data indicate a basolateral active uptake mechanism for nitrofurantoin, which remains to be identified. This mechanism may influence the exposure of suckling infants to xenobiotics, as well as having potentially toxic effects on the lactating mammary epithelium and possibly altering the nutritional quality of the milk.
authors.affiliation: Room 401A Pharmacy Building, University of Kentucky College of Pharmacy, Lexington, KY 40536-0082, USA.
authors.forename: Phillip M
authors.initials: PM
authors.lastname: Gerk
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Moscow
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: McNamara
mesh_terms: D000818:Animals; D001693:Biological Transport, Active; D002250:Carbon Radioisotopes; D002461:Cell Line, Transformed; D002463:Cell Membrane Permeability; D004848:Epithelium / Q000378:metabolism; D005260:Female; D007774:Lactation; D008321:Mammary Glands, Animal / Q000378:metabolism*; D009582:Nitrofurantoin / Q000493:pharmacokinetics*; D051381:Rats; D012588:Scintillation Counting
chemical_list: D002250:Carbon Radioisotopes; D009582:Nitrofurantoin