1966 Volume 29 Issue 3-4 Pages 85-103
Using radioactive isotope I131—NaI131 was mixed in 10% Na2SO3 solution, radio activity 100mc/ml, radio chemical purity 99.9%—, percutaneous absorption of iodide from bath water, peroral absorption after internal use of iodine containing mineral water, and the influence of absorbed iodine on the thyroid gland were studied in mice and rabbits.
Each mice was fixed in a small cage following the “bambootube” method of Masaji Seki, and bathed till the lower half of the body in the bath water at 37°-40°C, 20-30 minutes. NaI131 was added in the bath water to reach a radioactivity of 100-200μc/l. After the bath the surface of the animal body was washed out thoroughly with running water. Then the breast was cut open under anesthesia using chloroform or ether and blood was taken by heart puncture. The radioactivity (RA) of the blood was then measured by G-M counter or scintillation counter (well-typed).
Rabbit was bathed, fixed in a box, till the lower half of the body. The blood was taken from the ear vein. The radioactivity around the thyroid gland was measured by a survey meter.
For internal use of the waters, a thin polyvinyl tube with a diameter of 2mm was perorally inserted into the stomach of the mice. In the case of rabbit. Nelaton catheter was used.
To study function of the thyroid gland after serial oral administration of Mobara Mineral water, rabbits were given 5μc of I131. Then I131 uptake of the thyroid gland and plasma conversion rate after 24 hours were determined.
The investigations revealed the following results:
1. The longer was the duration of bath, the greater proved the amount of percutaneously absorbed iodine. Likewise, percutaneously absorbed iodine showed a tendency to increase as the temperature of bath water and as concentration of iodine in the bath water increased. It was recognized that iodide absorption continued still after the bath.
2. In relation to the influence of various co-existing ions upon the percutaneous absorption of I131, additon of sodium chloride, sodium sulfate, calcium chloride, or calcium sulfate at a concentration of 1g/l, showed an inhibition, while sodium bicarbonate, aluminium sulfate or pottasium bromide had a tendency to inhibit but not definitely. Especially, high concentration of sodium sulfate showed a strong inhibition, and in the case of sodium chloride similar finding was noted.
3. Concerning the effect of carbon dioxide and hydrogen sulfide an increase of percutaneous iodine absorption was demonstrated by the former.
4. After the serial daily bathings for 12 to 14 days in sodium sulfate solution, sodium chloride solution, or solution of pottasium iodide plus sodium chloride, respectively, an inhibition of percutaneous absorption of I131 was observed. As far as sodium chloride solution was concerned, the inhibition increased parallel with the length of the serial bathing period. On the other hand, after the serial bathings for 7 to 14 days in Kusatsu Hot Spring (H2S-containing acid spring), an inhibition of percutaneous absorption of I131 was demonstrated, while after 21 days of the serial bathings an tendency of recovery in the percutaneous absorption was observed.
5. In adult rabbits thyroid uptake of iodine, in the amount corresponding to 1.8ml of bath water, was proved 48 hours after bathing for 30 minutes at 40°C in a bath water containing iodine at a concentration of 200μc/l.
6. Oral adminitstration of water containing I131 (0.25μc/l) resulted in a much more greater absorption than bathing in I131 added water (500μc/l). Oral administration of sodium bicarbonate or sodium chloride solution following the oral intake of I131 revealed no remarkable influence upon the absorption of I131
7. After oral administration of Mobara Mine