FIG. 2.

Sodium-dependent ¹⁴C-MeAIB uptake after incubation of cultured trophoblast cells in control media, insulin (1 nmol/l), gAd (5 μg/ml) (A), or fAd (5 μg/ml) (B) for 24 h. Subsets of cells were pretreated with insulin (1 nmol/l) for 4 h and then exposed to 5 μg/ml gAd (IgAd) or fAd (IfAd) for an additional 20 h. Data are mean ± SEM for cells isolated from six different placentas. Insulin alone, gAd alone, and insulin + gAd (P < 0.01) significantly stimulated MeAIB uptake; however, insulin + fAd significantly (P < 0.001) reduced MeAIB uptake compared with insulin alone (RMANOVA with post hoc tests, *P < 0.05, **P < 0.01). C: Summary data of real-time PCR of system A amino acid transporter isoforms SNAT1, SNAT2, and SNAT4 after incubation of cultured trophoblast cells as indicated. Data are mean ± SEM for six placentas. Insulin significantly increased SNAT gene expression. In the presence of fAd, the effect of insulin on the mRNA expression of SNAT2 and SNAT4 was significantly reduced compared with both fAd and insulin treatment alone (RMANOVA, P < 0.01; Tukey-Kramer multiple comparisons post tests, *P < 0.05, ***P < 0.01). D: Representative Western blot of SNAT1, SNAT2, and SNAT4 expression after incubation of cultured trophoblast cells as indicated. E: Summary of SNAT2 protein expression levels. n = 6 for each treatment, RMANOVA, P < 0.01; Tukey-Kramer multiple comparisons post tests, *P < 0.05, **P < 0.01.