Abstract
With rats of Wistar strain, investigation was made on change in I131 uptake by the thyroid produced by local X-ray irradiation on it, and the following results were obtained :
1) I131 uptake by the thyroid (30 minute value) declined in both sexes in parallel with the dose of the irradiation. The decrease was significant when the dose was 1000 and 6000r.
2) Temporal change in the I131 uptake was followed for 2 hours after the irradiation and it was found that in a dose of 200 r no difference was observed from controls, but that in doses of 1000 and 6000r, the uptake showed significant decrease from control values. And the decrease was nearly in parallel with the dose of the irradiation.
3) Temporal change in the I131 uptake (30 minute value) during 24 hours after the irradiation varied according to the dosage.
4) Relatively long observation (2 hours to 7 days) of the I131 uptake (2 hours value) after the irradiation in doses of and 1000 and 6000r revealed that the uptake was inhibited in the early period, but that later it was conversely increased.
