Loss of Organ Specific Characteristics of Hog Thyroid Cells During Growth in vitro

Normal hog thyroid glands were treated with enzyme and the dispersed cells cultured in vitro. Radioactive iodide (I¹²⁵) was added to the growth medium so that the duration of synthesis of thyroglobulin, MIT, DIT, T₃, and T₄ could be measured. Thyroglobulin production was measured by radio-immunoelectrophoresis and tanned cell hemagglutination inhibition tests. The iodinated amino acids were analyzed by hydrolyzing cell sonicates and separating the iodoamino-acids by thin-layer chromatography. Radioactivity of each amino acid was detected by direct counting in a well scintillation counter and by observation of a radioautograph prepared from a duplicate chromatography plate. Thyroglobulin was synthesized during the first 3 days of in vitro growth. Radioactively labeled T₃ and T₄ were detected during this same time period. The synthesis of MIT and DIT continued for at least 2 additional days. Serum albumin containing I¹²⁵ was detected by radioimmunoelectrophoresis during the first 7 days of growth. Hog kidney cells when tested in an identical manner did not iodinate proteins or amino acids.