72 M. Desforges and others J Physiol 587.1 Jozwik M, Teng C, Timmerman M, Chung M, Meschia G & Battaglia FC (1998). Uptake and transport by the ovine placenta of neutral nonmetabolizable amino acids with different transport system afﬁnities. Placenta 19, 531–538. Kuruvilla AG, D’Souza SW, Glazier JD, Mahendran D, Maresh MJ & Sibley CP (1994). Altered activity of the system A amino acid transporter in microvillous membrane vesicles from placentas of macrosomic babies born to diabetic women. J Clin Invest 94, 689–695. Lacey HA, Nolan T, Greenwood SL, Glazier JD & Sibley CP (2005). Gestational proﬁle of Na+/H+ exchanger and Cl−/HCO3− anion exchanger mRNA expression in placenta using real-time QPCR. Placenta 26, 93–98. Ling R, Bridges CC, Sugawara M, Fujita T, Leibach FH, Prasad PD & Ganapathy V (2001). Involvement of transporter recruitment as well as gene expression in the substrate-induced adaptive regulation of amino acid transport system A. Biochim Biophys Acta 1512, 15–21. Lowry OH, Rosebrough NJ, Farr AL & Randall RJ (1951). Protein measurement with the Folin phenol reagent. J Biol Chem 193, 265–275. Mackenzie B & Erickson JD (2004). Sodium-coupled neutral amino acid (System N/A) transporters of the SLC38 gene family. Pﬂugers Arch 447, 784–795. Mahendran D, Byrne S, Donnai P, D’Souza SW, Glazier JD, Jones CJP & Sibley CP (1994). Na+ transport, H+ concentration gradient dissipation, and system A amino acid transporter activity in puriﬁed microvillous plasma membrane isolated from ﬁrst-trimester human placenta: Comparison with the term microvillous membrane. Am J Obstet Gynecol 171, 1534–1540. Mahendran D, Donnai P, Glazier JD, D’Souza SW, Boyd RDH & Sibley CP (1993). Amino acid (system A) transporter activity in microvillous membrane vesicles from the placentas of appropriate and small for gestational age babies. Pediatr Res 34, 661–665. Malina A, Daftary A, Crombleholme W, Markovic N & Roberts JM (2005). Placental system A transporter mRNA is not different in preeclampsia, normal pregnancy, or pregnancies with small-for-gestational-age infants. Hypertens Pregnancy 24, 65–74. Mizuno Y, Sotomaru Y, Katsuzawa Y, Kono T, Meguro M, Oshimura M, Kawai J, Tomaru Y, Kiyosawa H, Nikaido I, Amanuma H, Hayashizaki Y & Okazaki Y (2002). Asb4, Ata3, and Dcn are novel imprinted genes identiﬁed by high-throughput screening using RIKEN cDNA microarray. Biochem Biophys Res Commun 290, 1499–1505. Moe AJ (1995). Placental amino acid transport. Am J Physiol Cell Physiol 268, C1321–C1331. Novak DA, Beveridge MJ, Malandro M & Seo J (1996). Ontogeny of amino acid transport system A in rat placenta. Placenta 17, 643–651. Novak D, Lehman M, Bernstein H, Beveridge M & Cramer S (2006). SNAT expression in rat placenta. Placenta 27, 510–516. Pfeiffer R, Rossier G, Spindler B, Meier C, Kuhn L & Verrey F (1999). Amino acid transport of y+L-type by heterodimers of 4F2hc/CD98 and members of the glycoprotein-associated amino acid transporter family. EMBO J 18, 49–57. Roos S, Powell TL & Jansson T (2004). Human placental taurine transporter in uncomplicated and IUGR pregnancies: cellular localization, protein expression, and regulation. Am J Physiol Regul Integr Comp Physiol 287, R886–R893. Rosenthal NR, Jacob R & Barrett E (1985). Diabetes enhances activity of alanine transport in liver plasma membrane vesicles. Am J Physiol Endocrinol Metab 248, E581–E587. Schenerman MA & Kilberg MS (1986). Maintenance of glucagon-stimulated system A amino acid transport activity in rat liver plasma membrane vesicles. Biochim Biophys Acta 856, 428–436. Sibley CP, Coan PM, Ferguson-Smith AC, Dean W, Hughes J, Smith P, Reik W, Burton GJ, Fowden AL & Constancia M (2004). Placental-speciﬁc insulin-like growth factor 2 (Igf2) regulates the diffusional exchange characteristics of the mouse placenta. Proc Natl Acad Sci U S A 101, 8204–8208. Smith RJ, Dean W, Konfortova G & Kelsey G (2003). Identiﬁcation of novel imprinted genes in a genome-wide screen for maternal methylation. Genome Res 13, 558–569. Sugawara M, Nakanishi T, Fei Y-J, Huang W, Ganapathy ME, Leibach FH & Ganapathy V (2000a). Cloning of an amino acid transporter with functional characteristics and tissue expression pattern identical to that of system A. J Biol Chem 275, 16473–16477. Sugawara M, Nakanishi T, Fei YJ, Martindale RG, Ganapathy ME, Leibach FH & Ganapathy V (2000b). Structure and function of ATA3, a new subtype of amino acid transport system A, primarily expressed in the liver and skeletal muscle. Biochim Biophys Acta 1509, 7–13. Varoqui H & Erickson JD (2002). Selective up-regulation of system A transporter mRNA in diabetic liver. Biochem Biophys Res Commun 290, 903–908. Wang H, Huang W, Sugawara M, Devoe LD, Leibach FH, Prasad PD & Ganapathy V (2000). Cloning and functional expression of ATA1, a subtype of amino acid transporter A, from human placenta. Biochem Biophys Res Commun 273, 1175–1179. Yao D, Mackenzie B, Ming H, Varoqui H, Zhu H, Hediger MA & Erickson JD (2000). A novel system A isoform mediating Na+/neutral amino acid cotransport. J Biol Chem 275, 22790–22797. Zaitoun I & Khatib H (2006). Assessment of genomic imprinting of SLC38A4, NNAT, NAP1L5, and H19 in cattle. BMC Genet 7, 49. Acknowledgements The authors thank the midwives and nursing staff of St. Mary’s Hospital for their assistance in obtaining placentas. We also thank Alicia Requena-Jimenez for her technical assistance with the Western blotting. This work has been funded by The Wellcome Trust (078814/Z/05/Z). C 2009 The Authors. Journal compilation C 2009 The Physiological Society