methylthiouracil and Adenoma

The proliferation kinetics and DNA content of thyroid follicular cells in rats were studied by autoradiography and cytophotometry. Continuous treatment of animals with methylthiouracil (MTU) results in hyperplasia followed by tumour growth in the thyroid gland. The mitotic index (MI) increases from 0.006 +/- 0.002% in controls to 0.13 +/- 0.06% in hyperplasia and to 0.09 +/- 0.03% in malignant cells. The same is true for the labelling index (LI) which rises from 0.08 +/- 0.003% in controls to 1.4 +/- 1.1% in hyperplasia and to 1.0 +/- 0.6% in follicular adenomas. The S-phase duration (TS) is shortened from 8.0 +/- 1.2 hr in controls to 6.0 +/- 1.4 hr in animals treated for 9 months with MTU and prolonged to 15.4 +/- 2.1 hr in papillary carcinomas. In all MTU-treated animals a decrease in the value of the potential population doubling time (TPD) and thyroid weight doubling time (TD) was observed. The cell loss factor (phi) decreases in animals treated for 3 months with MTU and increases during the stage of tumour growth in the gland (animals treated 12-15 months with MTU). DNA measurements in the nuclei of hyperplastic and neoplastic thyroid tissues reveal cells with values exceeding that in control animals. However, no difference was found in the DNA content between thyroid adenomas and carcinomas, nor between thyroid hyperplasia and neoplasia.

Topics: Adenoma; Animals; Carcinoma; DNA; Hyperplasia; Interphase; Kinetics; Male; Methylthiouracil; Mitotic Index; Neoplasms, Experimental; Organ Size; Rats; Thyroid Gland; Thyroid Neoplasms; Time Factors

Topics: Adenocarcinoma; Adenoma; Animals; Methylthiouracil; Microscopy, Electron, Scanning; Neoplasms, Experimental; Neoplasms, Radiation-Induced; Rats; Thyroid Gland; Thyroid Neoplasms

The influence of hypophysectomy, triiodothyronine (T3), and thyroxine (T4) on the goitrogenic and tumorigenic activity of methylthiouracil (MTU) and 1-methyl-2-mercapto imidazol (MMI) was studied in rats. Hypophysectomy effectively prevented the development of thyroid hyperplasia and adenomas in MTU-treated animals. T3 reduced or abolished the weight loss of goitrogen-treated animals, and prevented the development of thyroid hyperplasia, adenomas, and pulmonary metastatic nodules. The effect of T4 was less pronounced, especially in MTU-treated animals. This hormone failed to neutralize the goitrogenic effect of MTU but it did reduce significantly the incidence of thyroid adenomas and prevented the appearance of pulmonary lesions. The biological effect of the thyroid hormones correlated with their effect on the serum levels of TSH, T3, and T4. The observations are compatible with the assumption that the tumorigenic effect of the two goitrogens depends upon a state of imbalance between TSH and T3.

Topics: Adenoma; Adrenal Glands; Animals; Body Weight; Drug Combinations; Hyperplasia; Hypophysectomy; Imidazoles; Methylthiouracil; Neoplasms, Experimental; Organ Size; Pituitary Gland; Rats; Rats, Inbred Strains; Thyroid Neoplasms; Thyrotropin; Thyroxine; Triiodothyronine

Topics: Adenoma; Age Factors; Animals; Body Weight; Carcinoma; Male; Methylthiouracil; Neoplasms, Radiation-Induced; Organ Size; Rats; Thyroid Gland; Thyroid Neoplasms; Time Factors; X-Rays

The nature of tumors appearing in the thyroid gland and in the lungs of mice fed two standard goitrogenic drugs (MTU and MII) has been studied. These tumors have been considered malignant on the basis of their morphological appearance and their occurrence in abnormal locations. Some investigatiors, however, have questioned that they are actually malignant. The present results indicate that these tumors are most likely not malignant even if it is shown that the pulmonary nodules are of thyroid origin. The thyroid adenomas disappear once the goitrogen is withdrawn, but thryoid enlargement pesists, and event 6 months after discontinuation of the goitrogenic treatment , pulmonary nodules are still produced. Evidence is presented that these nodules are emoli from hyperplastic thyroid tissue and not tumors.

Topics: Adenoma; Animals; Carcinoma, Hepatocellular; Diet; Glycolysis; Hyperplasia; Iodine; Liver Neoplasms; Lung Neoplasms; Male; Methimazole; Methylthiouracil; Mice; Mice, Inbred Strains; Oxygen Consumption; Thyroid Gland; Thyroid Neoplasms

Nuclear DNA content was measured in 3 normal, 9 hyperplastic and 16 neoplastic rat thyroid glands. Thyroid hyperplasia and tumor growth were induced after treatment of the animals with X-rays and methylthiouracil. In the control animals only diploid thyroid epithelial cells were observed. At the stages of diffuse and nodular thyroid hyperplasia, the total DNA content per nucleus indicated for a diploid chromosome number and only a few cells were hyperdiploid. In the thyroid adenomas and carcinomas a scattering of the diploid region and an increase in the number of hyperdiploid cells was found. Among the various types of thyroid tumors neither difference in the number of hyperdiploid cells, nor typical pattern of distribution of these cells in the histogram was found. The increased number of hyperdiploid cells in the hyperplastic and neoplastic thyroids suggest an increase in the proportion of the cells entering the cell cycle and does not indicate for appearance of a neoplastic stemline.

Topics: Adenocarcinoma; Adenoma; Animals; Carcinoma, Papillary; Cell Nucleus; Cystadenoma; DNA; DNA, Neoplasm; Epithelium; Hyperplasia; Male; Methylthiouracil; Neoplasms, Experimental; Neoplasms, Radiation-Induced; Rats; Thyroid Gland; Thyroid Neoplasms

Topics: Adenoma; Animals; Antigens, Neoplasm; Cystadenoma; Fluorescent Antibody Technique; Methylthiouracil; Neoplasm Transplantation; Neoplasms, Experimental; Rats; Thyroglobulin; Thyroid Neoplasms

Topics: Adenoma; Animals; Body Weight; Cricetinae; Cystadenoma; Female; Iodine Isotopes; Lung Neoplasms; Methylthiouracil; Neoplasms, Experimental; Organ Size; Thyroid Neoplasms

Topics: Adenoma; Animals; Antigens, Neoplasm; Cell Transformation, Neoplastic; Cystadenoma; Female; Fluorescent Antibody Technique; Hyperplasia; Methylthiouracil; Microsomes; Neoplasms, Experimental; Organ Specificity; Rats; Thyroid Neoplasms

Topics: Adenocarcinoma; Adenoma; Animals; Female; Golgi Apparatus; Hyperplasia; Methylthiouracil; Microscopy, Electron; Neoplasms, Experimental; Rats; Thyroid Neoplasms

Topics: Adenoma; Animals; Antithyroid Agents; Carcinogens; Carcinoma, Hepatocellular; Cysts; Female; Glucose; Goiter; Imidazoles; Kidney Diseases; Lactates; Liver Neoplasms; Male; Methimazole; Methylthiouracil; Mice; Mice, Inbred Strains; Ovarian Cysts; Oxygen Consumption; Thyroid Diseases; Thyroid Gland; Thyroid Neoplasms; Triiodothyronine

Topics: Adenoma; Animals; Humans; Methylthiouracil; Microscopy, Electron; Neoplasm Transplantation; Neoplasms, Experimental; Organoids; Rats; Thyroid Gland; Thyroid Neoplasms

Topics: Adenocarcinoma; Adenoma; Animals; Cell Nucleolus; Cell Nucleus; Golgi Apparatus; Hyperplasia; Methods; Methylthiouracil; Microscopy, Electron; Mitochondria; Neoplasms, Experimental; Organoids; Rats; Ribosomes; Thyroid Diseases; Thyroid Gland; Thyroid Neoplasms; Time Factors

Topics: Adenoma; Animals; Carcinoma; Carcinoma, Papillary; Cricetinae; Endoplasmic Reticulum; Golgi Apparatus; Methylthiouracil; Microscopy, Electron; Neoplasms, Experimental; Organoids; Thyroid Gland; Thyroid Neoplasms

Topics: Adenoma; Animals; Carcinogens; Carcinoma; Fluorenes; Methylthiouracil; Neoplasm Metastasis; Neoplasms, Experimental; Propylthiouracil; Rats; Thiouracil; Thyroid Neoplasms

Topics: Adenoma; Carcinogens; Methylthiouracil; Neoplasms; Neoplasms, Experimental; Pharmacology; Pituitary Neoplasms; Rats; Research; Thyroid Gland; Thyroid Neoplasms; Transplantation

Topics: Adenoma; Goiter; Graves Disease; Iodine; Methylthiouracil; Pathology; Pharmacology; Pituitary Gland; Rats; Research; Thyroid Neoplasms; Thyrotrophs; Triiodothyronine

Topics: Adenoma; Goiter; Histology; Humans; Iodine; Methylthiouracil; Neoplasm Metastasis; Neoplasms; Pathology; Thyroid Neoplasms

Topics: 2-Acetylaminofluorene; Adenoma; Iodine; Iodine Compounds; Lymphoma, Non-Hodgkin; Methylthiouracil; Neoplasms; Sarcoma; Thyroid Gland