Characterization of L-arginine transport in adrenal cells: effect of ACTH

1 Departamento de Bioquímica Humana, Facultad de Medicina; 2 Instituto de Biología y Medicina Experimental, and 3 Departamento de Quimica Biológica Facultad de Cs Exactas y Naturale, Universidad de Buenos Aires, Buenos Aires, Argentina Submitted 30 August 2005 ; accepted in final form 20 January 2006 Nitric oxide synthesis depends on the availability of its precursor L -arginine, which could be regulated by the presence of a specific uptake system. In the present report, the characterization of the L -arginine transport system in mouse adrenal Y1 cells was performed. L -arginine transport was mediated by the cationic/neutral amino acid transport system y + L and the cationic amino acid transporter (CAT) y + in Y1 cells. These Na + -independent transporters were identified by their selectivity for neutral amino acids in both the presence and absence of Na + and by the effect of N -ethylmaleimide. Transport data correlated to expression of genes encoding for CAT-1, CAT-2, CD-98, and y + LAT-2. A similar expression profile was detected in rat adrenal zona fasciculata. In addition, cationic amino acid uptake in Y1 cells was upregulated by ACTH and/or cAMP with a concomitant increase in nitric oxide (NO) production. nitric oxide; adrenocorticotropic hormone; protein kinase A Address for reprint requests and other correspondence: C. B. Cymeryng, Departamento de Bioquímica Humana, Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155 5° (1121ABG), Buenos Aires, Argentina (e-mail: cymeryng{at}fmed.uba.ar )