Cellular accumulation of 14Cmethylaminoisobutyric acid by system A is lower in placentas of growth restricted compared to normally grown fetuses

Human placental uptake of glutamine and glutamate is reduced in fetal growth restriction

“…2 B–D). It is also postulated that a reduction in initial rate uptake of glutamine and glutamate will lead to a lower intracellular concentration in placentas of FGR compared with AGA pregnancies 36 . Reductions in amino acid availability thus offer a rationale as to why fetal growth may be compromised in FGR.…”

“…Fragments were maintained in medium (DMEM 1880028: Gibco) supplemented with alanine (341 µM), glutamine (418 µM), glutamic acid (69 µM) and taurine (44 µM), streptomycin sulphate (100 mg/L), penicillin (60 mg/L) and gentamicin (1 ml/L) on Netwell permeable supports (Corning: 74 µM mesh; in a humidified incubator (37 ºC; 95 % air/5 % CO 2 )). To measure amino acid uptake at steady state 36 , fragments were incubated for 24 h with: 0.5 µCi/ml (8.5 nmol/ml) 14 C-MeAIB; 0.066 µCi/ml (0.24 nmol/ml) 14 C-glutamine; 0.13 µCi/ml (0.5 nmol/ml) 14 C-glutamate; or 0.5 µCi/ml (8.5 nmol/ml) 14 C-3-0-methylglucose (3-0MG). 3-0MG is a non-metabolised substrate of the GLUT transporters and uptake of 3-0MG was measured to assess whether rapamycin had nonspecific effects on transporters and/or an effect on placental villus tissue integrity.…”