Placental transport of leucine in a porcine model of low birth weight.
Low birth weight is a major factor in neonatal morbidity and mortality in humans and domestic species and is a predictor of physiological disorders in adulthood. This study utilised the naturally occurring variation in pig fetal size within a uterus to test the hypothesis that placental amino acid transport capability is associated with fetal growth. Leucine uptake by trophoblast vesicles prepared from placentas supplying an average-sized fetus and the smallest fetus in the uterus was assessed. On days 45 and 65 of gestation, uptake of leucine by the porcine placenta was predominantly sodium independent and was inhibited by the non-metabolised leucine analogue 2-amino-2-norbornane-carboxylic acid, indicating that uptake occurs via system L. By day 100 the uptake of leucine by placentas supplying average-sized fetuses had changed from being predominantly sodium independent to involving both sodium-dependent (system B0) and -independent (system L) pathways. This change was not seen in placentas supplying the smallest fetus, which continued to display predominantly sodium-independent uptake. In conclusion, these data show gestational- and fetal size-dependent changes in the transport of leucine across the porcine placenta.
Finch
Angela M
AM
Development, Growth and Function Division, Rowett Research Institute, Bucksburn, Aberdeen AB21 9SB, UK.
Yang
Li G
LG
Nwagwu
Margaret O
MO
Page
Kenneth R
KR
McArdle
Harry J
HJ
Ashworth
Cheryl J
CJ
D000818:Animals; D001692:Biological Transport / Q000502:physiology; D001724:Birth Weight; D005260:Female; D005317:Fetal Growth Retardation / Q000378:metabolism*; D005865:Gestational Age; D007930:Leucine / Q000378:metabolism*; D023421:Models, Animal; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D015398:Signal Transduction / Q000502:physiology*; D012964:Sodium / Q000378:metabolism; D013552:Swine
D012964:Sodium; D007930:Leucine