Studies on the regulation of RNA labeling and on the biochemical constituents of normal and abnormal human thyroid.

The present studies were performed in order to analyze the incorporation of 3H-uridine into RNA and its hormonal regulation as well as the content of total iodine, T3, T4, RNA, DNA and protein in normal and abnormal human thyroid obtained at surgery. The content of protein, RNA and DNA is not significantly changed in follicular adenoma and in adenomatous goiter, RNA labeling from 3H-uridine showed similar values in slices from normal and abnormal glands. TSH and cyclic AMP increased the labeling of RNA in normal tissue but had no effect in the follicular adenoma and adenomatous goiter. A significant decrease in total iodine, T3 and T4 concentration was found in the pathological samples when compared to normals. The present results would suggest that in these patients the biochemical abnormalities lie at a step distal to the TSH receptor and the adenylate cyclase.