[Accumulation mechanism of 201Tl--K-contents and Na, K-ATPase activities of tissues].

Though the mechanism of 201Tl accumulation in thyroid tumours is not known yet, there are some hypotheses. In order to study the mechanism, potassium contents and Na, K-ATPase, of various organs of rats and human thyroid glands were analyzed . The conclusion through these experiments is as follows, 1 as the potassium contents and Na, K-ATPase activity of thyroid glands are not obviously higher than those of other organs, the 201Tl accumulation in thyroid is thought to be not owing to the similarity to the potassium ion, 2 pointing out high activity of Na, K-ATPase in heart and kidney, the accumulation mechanism of 201Tl in these organs has high relation to this activity, 3 though there is a tendency to have higher potassium contents among thyroid tumours, the difference in potassium contents between their histopathology is small; so that the tumour specificity is not explained from the potassium contents, and 4 as for Na, K-ATPase activity of thyroid tumours, papillary adenocarcinoma and follicular adenoma, which take more in 201Tl, have tendency to show higher activity; adenomatous goitre, which take less in 201Tl, has tendency to show lower activity. We suggested that the factor relating to the accumulation mechanism of 201Tl may be multiple, and Na, K-ATPase plays an important role in 201Tl specific uptake in thyroid tumours.