Effects of MUN on the level of SLC38A protein expression in labyrinth zone from mid- and proximal-horn placentas. Representative immunoblots of SLC38A1 (A), SLC38A2 (B) and SLC38A 4 (C) protein expression. Densitometric analysis of SLC38A1 (D), SLC38A2 (E), and SLC38A4 (F) protein expression. a indicates a significant difference between zone weights from MUN (black bars) vs. AdLib (open bars). bindicates a significant difference between mid- and proximal-horn placental positions.