[Characteristics of thyrocyte multiplication in proliferating thyroid epithelium].

Although the thyroid parenchyma is characterized by high proliferative ability, mitoses in it are seldom observed. Earlier it was considered that the main type of thyrocyte reproduction was amitotic division. However, biochemical investigations of late showed that the thyroid parenchyma during rapid growth in tissue culture intensively incorporated thymidine, this being an evidence of DNA replication indicating mitoses.

[Absorption of radioactive iodine by cells of the follicular and interfollicular epithelia of the thyroid gland].

Autoradiography was used in experiments on male rats to measure the accumulation of a single dose of 131I (1 microCi) injected intraperitoneally by cells of the thyroid parenchyma proper. A calculation was made of the number of tracks above the cytoplasm of thyrocytes, follicular buds, interfollicular thyrocytes and microfollicular thyrocytes 3, 6, 9, 12, 24, 48 and 96 h after the isotope injection. It was ascertained that cell components of the thyroid gland undergoing different stages of proliferation do not lose their genome specificity.