Displaced chromatographic elution of gastrin-17 in normal human serum

Sulfated gastrin-17 elutes by gel chromatography significantly earlier after incubation in human serum (KD: 0.48) than when added to buffer (KD: 0.62). Also, the elution of non-sulfated gastrin-17 changes after serum incubation although to a lesser extent (KD: 0.68 vs. 0.74). In contrast neither the N-terminal 1-13 nor the sulfated C-terminal hexapeptide fragment of gastrin-17 change elution positions after serum incubation. The earlier elution is concentration dependent. The results suggest that displaced elution of sulfated gastrin-17 may constitute part of the abundance of gastrin-34-like material in normal human serum. Hence, present concepts of gastrin heterogeneity in serum seem to require re-evaluation.