Fig. 1.

Chromatograms of agmatine and ¹³C₄-agmatine in various matrices. Peaks of (A) agmatine at LLOQ (5 ng/ml) in 5% BSA; (B) agmatine at LLOQ in rat plasma; (C) agmatine at LLOQ in rat CNS homogenate; (D) blank 5% BSA; (E) blank rat plasma; (F) blank rat CNS homogenate; (G) ¹³C₄-agmatine in 5% BSA; (H) ¹³C₄-agmatine in rat plasma; (I) ¹³C₄-agmatine in rat CNS homogenate; and (J) blank mobile phase (97% H₂O, 3% acetonitrile, 0.1% formic acid). AA, automatic area; AH, automatic height; RT, retention time; SN, signal to noise.