Figure 3. Net Renal Release of Select Metabolites.
Aortic and renal venous levels for creatinine, serine, arginine, and tyrosine, reported as peak areas detected by the mass spectrometer. The uniform decrease in creatinine is a positive control, consistent with renal clearance. Serine and arginine increased from aorta to renal vein in all nine individuals, whereas tyrosine increased in seven individuals (P < 0.001 for all three metabolites).