Figure 1. Characterization of WE-14 in plasma.

(A) Semilogarithmic plots comparing competitive inhibition of antibody-bound ¹²⁵I-labeled Tyr₀-WE-14 by synthetic human WE-14 (•) and serial dilutions of plasma samples from healthy volunteer (▴), post-operative (▪) and preoperative (♦) patients with benign pheochromocytoma. (B, C) Reversed-phase HPLC analysis of WE-14 immunoreactivity in plasma samples from a healthy volunteer (B) and a patient with benign pheochromocytoma (C). The bars above the peaks indicate the elution position of synthetic human WE-14 (peak I) and its oxidized form (peak II) chromatographed the same day as the extracts. The dashed line shows the concentration of acetonitrile in the eluting solvent.