INFγ stimulates arginine transport through system y + L in human monocytes

Freshly isolated human monocytes transport l ‐arginine mostly through a sodium independent, NEM insensitive pathway inhibited by l ‐leucine in the presence, but not in the absence of sodium. Interferon‐γ (IFNγ) stimulates this pathway, identifiable with system y + L, and markedly enhances the expression of SLC7A7, the gene that encodes for system y + L subunit y+LAT1, but not of SLC7A6, that codes for the alternative subunit y+LAT2. System y + plays a minor role in arginine uptake by monocytes and the expression of system y + ‐related genes, SLC7A1 and SLC7A2, is not changed by IFNγ. These results demonstrate that system y + L is sensitive to IFNγ.