Screening of commonly prescribed drugs for effects on the CAT1-mediated transport of L-arginine and arginine derivatives.

The cationic amino acid transporter 1 (CAT1/SLC7A1) plays a key role in the cellular uptake or export of L-arginine and some of its derivatives. This study investigated the effect of 113 chemically diverse and commonly used drugs (at 20 and 200 µM) on the CAT1-mediated cellular uptake of L-arginine, L-homoarginine, and asymmetric dimethylarginine (ADMA). Twenty-three (20%) of the tested substances showed weak inhibitory or stimulatory effects, but only verapamil showed consistent inhibitory effects on CAT1-mediated transport of all tested substrates.