To investigate the effect of shaking on the liberation of iodine containing amino acid from thyroid tissue, I133-labelled rat thyroid homogenate was incubated in incubation medium at 37.5°C about one hour with or without shaking, and then this mixture was investrgated by paperchromatography. The results obtained were as follows :
Liberated form of I131-labelled amino acid both in the thyroid homogenate and in the incubation medium were apparently increased by shaking.