title: Placental lactate transporter activity and expression in intrauterine growth restriction.
abstract: OBJECTIVE
  To compare lactate uptake in the microvillous plasma membrane (maternal facing [MVM]) in term and preterm placentas in intrauterine growth restriction (IUGR) and appropriate weight for gestational age (AGA) controls, and in the basal plasma membrane (fetal facing [BM]) at term. In addition, we examine the expression of monocarboxylate transporters (MCT1 and MCT4).
  
  
  METHODS
  We measured [14C] L-lactate uptakes into vesicles prepared from MVM and BM, stimulated by an inwardly directed H+ gradient. MCT expression was examined by Western blotting.
  
  
  RESULTS
  In term placentas, mean (+/- SE) [14C] L-lactate uptake into MVM vesicles of the IUGR (n = 6) and AGA (n = 11) groups at initial rate was similar (15.4 +/- 2.3 versus 15.0 +/- 1.1 pmol/mg protein/20 s). In preterm placentas, in IUGR (n = 3) and AGA (n = 3) groups, [14C] l-lactate uptake into MVM was also not significantly different. In BM vesicles from term placentas, [14C] L-lactate uptake was significantly lower in IUGR (n = 5) than in AGA (n = 6) controls (3.6 +/- 0.4 versus 5.6 +/- 0.6 pmol/mg protein/20 s, P <.05). MCT1 and MCT4 were expressed in BM vesicles, but there was no difference in expression between the IUGR and AGA groups.
  
  
  CONCLUSIONS
  These findings suggest that in IUGR placental lactate transport capacity in the BM is reduced, which may adversely affect placental lactate clearance.
authors.affiliation: Division of Human Development, University of Manchester, St. Mary's Hospital, Manchester, United Kingdom.
authors.forename: Paul
authors.initials: P
authors.lastname: Settle
authors.forename: Colin P
authors.initials: CP
authors.lastname: Sibley
authors.forename: Ian M
authors.initials: IM
authors.lastname: Doughty
authors.forename: Tracey
authors.initials: T
authors.lastname: Johnston
authors.forename: Jocelyn D
authors.initials: JD
authors.lastname: Glazier
authors.forename: Theresa L
authors.initials: TL
authors.lastname: Powell
authors.forename: Thomas
authors.initials: T
authors.lastname: Jansson
authors.forename: Stephen W
authors.initials: SW
authors.lastname: D'Souza
mesh_terms: D000653:Amniotic Fluid; D015153:Blotting, Western; D002250:Carbon Radioisotopes; D005260:Female; D005317:Fetal Growth Retardation / Q000378:metabolism*; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D019344:Lactic Acid / Q000378:metabolism*; D027501:Monocarboxylic Acid Transporters / Q000032:analysis / Q000235:genetics* / Q000378:metabolism*; D009124:Muscle Proteins / Q000032:analysis; D010920:Placenta / Q000737:chemistry* / Q000378:metabolism*; D011247:Pregnancy; D011522:Protons; D016216:Ultrasonography, Prenatal
chemical_list: D002250:Carbon Radioisotopes; D027501:Monocarboxylic Acid Transporters; D009124:Muscle Proteins; D011522:Protons; C406962:SLC16A4 protein, human; D019344:Lactic Acid