Does Sulfation of Gastrin Influence Gastric Acid Secretion in Man?

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Abstract
To assess the physiologic significance of tyrosine o-sulfation of gastrin in humans, the gastric acid stimulatory potencies of sulfated and non-sulfated human gastrin-17 were compared in six normal young subjects. Sulfated and non-sulfated forms of synthetic human gastrin-17 were infused intravenously in doses from 12.7 to 478 pmol/ kg/h. Similar acid secretory responses were observed. The calculated maximal acid response for sulfated gastrin-17 was 35.7 ± 4.3mmol/h, and that for non-sulfated gastrin-17 was 39.8 ± 7.5 mmol/h (mean ± SEM, NS). The 50% effective dose of sulfated gastrin-17 was 22.2 ± 6.7pmol/kg/h, whereas it was 29.3 ± 5.8pmol/kg/h for non-sulfated gastrin-17 (NS). Finally, the 50% effective concentration of gastrin in serum was 34.7 ± 5.0 pmol sulfated gastrin-17/1 and 42.5 ± 11.8 pmol non-sulfated gastrin-17/1 (NS). The results show that tyrosine o-sulfation is without significant influence on the gastric acid secretory potency of gastrin in man. Moreover, the results also suggest that sulfated and non-sulfated gastrin-17 in man have similar rates of metabolism.