Comparison of the metabolism of sulfated and unsulfated heptadecapeptide gastrin in humans.
The metabolism of synthetic human sulfated heptadecapeptide gastrin (G-17) was studied in normal human volunteers. Plasma concentrations were measured by radioimmunoassay using antibodies specific for intact G-17, and for the C- and N- terminus of G-17, during and after infusion of both sulfated and unsulfated G-17. With all three antibodies, plasma concentrations at a steady state were higher during infusion of sulfated compared with unsulfated G-17. In addition, the half-life in plasma measured by the three antibodies was two to five times higher for sulfated G-17 compared with unsulfated G-17. The half-life measured by N-terminal-specific antibodies was greater than that with antibodies specific for C-terminal or intact G-17. The difference was accounted for by the production during infusion of N-terminal fragments of relatively long half-life. The pattern of fragments generated during infusion of sulfated G-17 resembled that during unsulfated G-17 infusion, but there was no evidence of desulfation in the systemic circulation. The results indicate that in humans, sulfation protects G-17 from metabolism.
D000328:Adult; D005260:Female; D005755:Gastrins / Q000097:blood*; D006207:Half-Life; D006801:Humans; D008297:Male; D008875:Middle Aged; D011487:Protein Conformation; D011863:Radioimmunoassay; D011897:Random Allocation; D013431:Sulfates / Q000097:blood
D005755:Gastrins; D013431:Sulfates; C013550:gastrin 17