Abstract
(The numbers correspond to section numbers in the text.)
1. The quantitative absorption of sodium iodide from the gastrointestinal tract is practically the same in dogs and in cats.
2. The average absorption is approximately the same for all divisions of the small intestine; from the stomach and colon it is about a third less.
3. The extent of surface does not influence the percentage of absorption.
4. One, 2 and 5 per cent solutions of sodium iodide are absorbed with about the same ease; a 10 per cent solution somewhat more readily.
5. The absorption from the intestine is at first very rapid so that 50 per cent to 75 per cent are absorbed within ten minutes. By that time the absorption is greatly checked or completely arrested so that 25 per cent to 50 per cent may remain unabsorbed at the end of two hours.
6. The checking of the absorption in a loop containing iodide does not affect absorption in other loops.
7. Stoppage of absorption is not due to the systemic action of sodium iodide.
8. Re-excretion is not responsible for the arrest of absorption.
9. In general there is practically no relation between the absorption and variations in blood pressure unless the pressure reaches a very low level (35 mm.) when the absorption is diminished, but it may be fairly efficient even at this level.
10. Visible hyperemia increases and visible anemia diminishes the absorption of iodide.
11. Injury of the intestinal epithelium, however produced, hinders the absorption.
12. The inhibition of absorption of sodium iodide is a local effect; the explanation must be sought in some chemical change in the absorbing epithelium.
13. Sodium iodide does not easily permeate the excised intestine. Certain substances increase the permeability.
14A. Post-mortem absorption of iodide is considerable and quite constant.
B. A considerable amount of the iodide is retained in the wall of the intestine during life.
15. The application of dilute (0.2 to 1 per cent) sodium chloride to the intestinal mucosa inhibits the absorption of sodium iodide.
16. It is doubtful whether absorption of iodide is inhibited by rendering the tissues at large rich in haloid.
17. It is doubtful whether the absorption of iodide is materially increased by rendering the tissues poor in chlorides.
The course of the absorption of iodide is superficially very similar to that of phenol. Both show a rapid initial absorption, succeeded by a marked inhibition of absorption. The mechanism of this absorption, however, is entirely different in the two cases. With phenol, the inhibition is due to an interference with the circulation, which may be brought about by systemic or local application. With iodide, the effect is directly on the absorbing epithelium, and occurs only on direct contact with a haloid salt. It is well known that contact with haloids also alters the permeability of the kidney cells to haloids. The two facts are presumably related.
Footnotes
- Received February 8, 1912.
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