Glycine and L-arginine transport in cultured Müller glial cells (TR-MUL).

We have reported previously that creatine is biosynthesized from glycine and L-arginine in Müller cells, but the mechanism responsible for glycine and L-arginine uptake by Müller cells remains elusive. To explore this issue, [(14)C]glycine and [(3)H]L-arginine uptake by Müller cells was characterized using a conditionally immortalized rat Müller cell line (TR-MUL5 cells). [(14)C]Glycine uptake by TR-MUL5 cells was Na(+)- and Cl(-)-dependent, and a saturable process with Michaelis-Menten constants of 48.