View article

Arginine is an essential amino acid for conceptus (embryo/fetus and trophoblast/placenta) growth and development; however, the mechanisms for arginine transport into the uterine lumen and uptake by conceptuses are largely unknown. In this study, expression of System y⁺ (SLC7A1, SLC7A2, and SLC7A3) cationic amino acid transporters in uteri of cyclic and pregnant ewes and conceptuses was studied, and effects of pregnancy, progesterone (P4), and interferon tau (IFNT) on their expression were investigated. SLC7A1 mRNA was most abundant in endometrial luminal (LE) and superficial glandular (sGE) epithelia on Day 16 of the estrous cycle and on Days 16–20 of pregnancy, whereas SLC7A2 mRNA was most abundant in LE and mid to deep glandular (GE) epithelia on Days 14–20 of gestation. Expression of SLC7A1 and SLC7A2 was enhanced in pregnant ewes in a cell-specific manner, but …