Gastric iodide secretion

Sodium Iodide Symporter (NIS) in Gastric Mucosa Gastric Iodide Secretion... 

Studies on bovines showed a recirculation of iodide, and this was suggested to be an important iodide-conserving mechanism (Miller et ai, 1975b). The functional role of iodide secretion into the gastric lumen has, however, remained elusive. 

Iodide secretion into the gastric lumen is mediated by NIS. 

Because investigators were chiefly interested in the behavior of in tracer amounts, no one made a systematic study of iodide secretion over a wide range on plasma concentrations. In fact, one pair of investigators said that unlike thyroid accumulation of iodide, gastric secretion of iodide is not depressed by administration of stable iodide. The data in Figure 1-14 were available to contradict them. 

This compound had rather remarkable antlsecretory properties It Inhibited gastric acid secretion, whatever the stimulus It Inhibited secretion In Isolated gastric glands, whatever the stimulus, but was relatively acid unstable and showed Inhibition of Iodide uptake by the thyroid and was thymotoxic. 

In addition, Pfister and coworkers investigated 3-hydroxyflavone-6-carboxylic acids as histamine induced gastric secretion inhibitors. After condensing 3-acetyl-4-hydroxybenzoic acid (45) with a variety of aldehydes 46 to deliver the chalcones 47, these purified chalcones were then subjected to the standard AFO conditions to afford flavonols 48 in 51-80% yield. Subsequent alkylation of 48 with methyl iodide or isopropyl iodide followed by saponification of the corresponding esters gave the target compounds. 

In complete ignorance of Lipschitz s work, I undertook a study of gastric secretion of iodide in 1939-40 when I was at the University of Rochester, and I continued it when I moved to Yale. I gave sodium iodide intravenously and collected simultaneous samples of pouch gastric juice and of venous blood. I measured total... 

Figure 1-15. A Ordinates, ratio of the concentration of iodide in gastric juice to that in plasma. Abscissae, plasma iodide concentration in millimoles per liter. B Ordinates, gastric juice iodide concentration in millimoles per liter. Abscissae, plasma iodide concentration in millimoles per liter. C Ordinates, ratio of iodide concentration in plasma to that in gastric juice. Abscissae, plasma iodide concentration in millimoles per liter. (From Davenport HW. The secretion of iodide by the gastric mucosa. Gastroenterology 1 1055-1061, 1943.)... 

After I had studied the secretion of bromide and iodide, it was obvious that the next anion I should study was thiocyanate. I fed my pouch dogs sodium thiocyanate, stimulated them to secrete by subcutaneous injections of histamine, and attempted to collect their gastric juice. I was frustrated by the scantiness of secretion, and eventually I realized that thiocyanate was inhibiting acid secretion. My friend Joseph F. Ross, who was also a fellow in pathology at Rochester, suggested that thiocyanate might be inhibiting carbonic anhydrase. I made the appropriate test and found that the enzyme is indeed inhibited by thiocyanate. 

Davenport HW. The secretion of iodide by the gastric mucosa. Gastroenterology 1 1055-1061, 1943. 

Mason EE, Bloch HS. Gastric secretion of iodide at low serum iodide level. Proc Soc ExpBiolMedl3 4SS-49l, 1950. 

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