methylthiouracil and Carcinoma

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

Topics: Animals; Carcinoma; Carcinoma, Papillary; Cell Nucleus; Cell Transformation, Neoplastic; Chromatin; DNA; Epithelial Cells; Epithelium; Hyperplasia; Male; Methylthiouracil; Microscopy, Phase-Contrast; Rats; Spectrophotometry; Staining and Labeling; Thyroid Neoplasms; Time Factors

Topics: Adenocarcinoma; Administration, Oral; Animals; Carcinoma; Carcinoma, Papillary; Injections, Intravenous; Methylthiouracil; Neoplasms, Experimental; Nitrosourea Compounds; Rats; Thyroid Neoplasms; Time Factors

The effect of the administration of L-thyroxine and of methylthiouracil alone, together, in combination with stilboestrol or in the perinatal period on the induction of cervico-vaginal tumours by weekly local applications of DMBA was investigated in intact and castrate rats and compared with carcinogenesis in animals not additionally treated.In intact rats the rate of sarcoma induction is accelerated by methylthiouracil, delayed and reduced by methylthiouracil plus L-thyroxine and delayed by perinatal injection of either L-thyroxine or methylthiouracil. In castrates sarcoma induction is accelerated and increased by L-thyroxine, methylthiouracil and by combination of either substance with stilboestrol; it is accelerated but not significantly increased by combined treatment with the thyroactive compounds.The incidence of epithelial neoplasms is accelerated and increased in intacts and in castrates by methylthiouracil. This effect is slightly reduced in intacts but potentiated in castrates by additional stilboestrol treatment as well as by administration of L-thyroxine plus methylthiouracil.The incidence of sarcomas is significantly greater in intact than in spayed rats not additionally treated, greater in castrates than in intacts given L-thyroxine ± stilboestrol and not significantly different in intacts and castrates with any of the other additional medications. For epithelial tumours the incidence is low and similar in both groups without additional treatment, greater in spayed than intact animals given methylthiouracil plus stilboestrol or plus L-thyroxine.The influence of the thyroactive compounds on the induction of epithelial and sarcomatous tumours is not correlated with their effect on gain in body weight nor on growth of the stroma and of the epithelium of the vagina, cervix and uterus. Changes induced in the thyroid gland and the hypophysis are not correlated with those on carcinogenesis.Central and local factors may account for the differential response in carcinogenesis of intacts and castrates as well as of the epithelial and connective tissue of the cervico-vaginal tract to medication with thyroactive compounds.

Topics: Animals; Benz(a)Anthracenes; Body Weight; Carcinoma; Castration; Diethylstilbestrol; Drug Synergism; Female; Methylthiouracil; Neoplasms, Experimental; Papilloma; Pituitary Gland; Rats; Sarcoma, Experimental; Skin; Thyroid Gland; Thyroxine; Urogenital System; Uterine Cervical Neoplasms; Vaginal Neoplasms

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

Topics: Abnormalities, Drug-Induced; Aniline Compounds; Animals; Benz(a)Anthracenes; Carcinoma; Carcinoma, Squamous Cell; Female; Gestational Age; Hydrocephalus; Kidney Neoplasms; Maternal-Fetal Exchange; Methylthiouracil; Microcephaly; Neoplasms, Germ Cell and Embryonal; Nitroso Compounds; Pregnancy; Pregnancy, Animal; Rats; Thyroid Neoplasms; Urea; Urethane

Topics: Animals; Benz(a)Anthracenes; Carcinoma; Castration; Diethylstilbestrol; Female; Male; Methylthiouracil; Neoplasms, Experimental; Rats; Salivary Gland Neoplasms; Sarcoma; Sex; Thyroxine

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