TY - JOUR T1 - BASOLATERAL ACTIVE UPTAKE OF NITROFURANTOIN IN THE CIT3 CELL CULTURE MODEL OF LACTATION JF - Drug Metabolism and Disposition JO - Drug Metab Dispos SP - 691 LP - 693 DO - 10.1124/dmd.31.6.691 VL - 31 IS - 6 AU - Phillip M. Gerk AU - Jeffrey A. Moscow AU - Patrick J. McNamara Y1 - 2003/06/01 UR - http://dmd.aspetjournals.org/content/31/6/691.abstract N2 - 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 (μl/h)/cm2] was differentially decreased by unlabeled nitrofurantoin (250 μM) on the basolateral, apical, or both sides [49.5 ± 1.8, 57.9 ± 1.4, or 48.5 ± 1.6 (μl/h)/cm2, respectively]. Apical to basolateral permeability [27.6 ± 1.8 (μl/h)/cm2] was increased in the presence of unlabeled nitrofurantoin (250 μM) on the basolateral, apical, or both sides [36.4 ± 1.5, 39.9 ± 0.7, 42.4 ± 1.1 (μl/h)/cm2, 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. The American Society for Pharmacology and Experimental Therapeutics ER -