methylthiouracil and Body-Weight

This study investigates the influence of low dosages of beta-agonists combined with other growth promoters on screening and confirmation methods in male veal calves. Five groups of four calves were treated for 6 weeks with combinations of low dosages of beta-agonists (beta AG, clenbuterol, mabuterol and mapenterol, 0.4 microgram/kg each twice daily) in combination with 17 beta-estradiol (E2, 5 mg per animal per 14 days), methylthiouracil (MTU, 2.857 mg/kg bw twice daily) and dexamethasone (DEX, 4 mg per animal per 10 days during the last 20 days of treatment). Another group of four untreated animals served as controls. The weight and size of the thymus was reduced in the DEX group, the MTU group showed enlarged thyroids. Histologically the prostates showed vacuolar degeneration in the beta AG animals and metaplasia in the E2 group. Some vacuolization was also observed in the controls. The testis showed impaired development in all treatment groups, E2 leading to the most severe changes. DEX led to cortical atrophy of the thymus. MTU induced hyperplastic changes in the thyroid. These results indicate that comedication does not markedly affect the histological changes induced in the hormonal target tissues. For screening purposes histology of the prostate can be used as a marker for oestrogens, whereas the weight of the thymus and thyroid can be used as an indication for the use of corticosteroids and thyreostatics, respectively. Vacuolization in the prostate appeared no reliable indication for beta-agonists. Samples of urine, faeces, liver and eye (retina/choroid) were analysed for beta-agonists. E2 significantly increased the levels of all beta-agonists in the liver and faeces, whereas DEX significantly reduced these levels. These observations show that additional medication with different groups of growth promoters can markedly alter the excretion of beta-agonists and thus influence (regulatory) control.

Topics: 2-Hydroxyphenethylamine; Adrenergic beta-Agonists; Aniline Compounds; Animals; Body Constitution; Body Weight; Cattle; Clenbuterol; Dexamethasone; Estradiol; Growth; Male; Meat; Metaplasia; Methylthiouracil; Organ Size; Prostate; Thymus Gland

Topics: Adult; Body Weight; Energy Intake; Female; Humans; Hyperthyroidism; Male; Methimazole; Methylthiouracil; Middle Aged

The effects of 4-methyl-2-thiouracil (MTU, 0.1% in drinking water) on the composition and cross-sectional area of muscle fibres of the rat soleus muscle were studied. The percentage of fast twitch-oxidative-glycolytic (FOG) fibres fell after 2 weeks of treatment with MTU to zero at 8 weeks. In contrast the percentage of FOG fibres in untreated animals fell to 19.2 +/- 2.1% during this period. The mean cross-sectional area of FOG and slow twitch-oxidative (SO) fibres were respectively 39.9% and 23.8% smaller than those of their respective controls 6 weeks after treatment. At 8 weeks the percentage reduction of SO fibre area was 26.8% of the control value. This study indicates that MTU treatment causes atrophy and redistribution of fibre type in the soleus muscle.

Topics: Animals; Body Weight; Histocytochemistry; Male; Methylthiouracil; Muscles; Rats

Experiments in 16-week old male Wistar strain rats showed that deficiency of thyroid hormones caused a decrease of cytochrome aa3, RNA, myofibrillar and sarcoplasmic protein contents in m. quadriceps femoris, Mg2+ activated actomyosin ATPase activity and physical working capacity of untrained and trained animals also reduced. Physical activity the intensity of which corresponded to metabolic power output of 190%. Vo2max stimulated thyroid function, elicited a significant elevation of blood thyroxine level, oxidative potential and intensity of protein synthesis in m. quadriceps femoris, the character of these changes depending on the type of muscle fibers. The stimulation of thyroid function caused an elevation of muscle content of cytochrome aa3 and content of RNA, especially in the glycolytic fibers of hypothyroid rats.

Topics: Adaptation, Physiological; Adrenal Glands; Animals; Body Weight; Cytochromes; DNA; Male; Methylthiouracil; Muscle Proteins; Muscles; Organ Size; Physical Exertion; Rats; RNA; Temperature; Thyroid Gland

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

Topics: Animals; Birds; Body Weight; Feathers; Female; Gonads; Iodine; Liver; Male; Methylthiouracil; Organ Size; Regeneration; Thyroid Gland; Thyroidectomy

Topics: Animals; Appetitive Behavior; Biometry; Body Weight; Dose-Response Relationship, Drug; Epithelial Cells; Epithelium; Male; Methylthiouracil; Organ Size; Rats; Staining and Labeling; Thyroid Gland

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

Topics: Animals; Antithyroid Agents; Blood Flow Velocity; Body Weight; Carbimazole; Imidazoles; Iodine Isotopes; Male; Methylthiouracil; Organ Size; Radioisotopes; Rats; Rubidium; Thyroid Gland; Time Factors

Topics: Adrenal Glands; Aggression; Animals; Body Weight; Endocrine Glands; Humans; Lithium; Male; Methylthiouracil; Polyuria; Rats; Seminal Vesicles; Thirst; Thyroid Function Tests; Thyroid Gland; Time Factors

Topics: Adrenal Cortex Hormones; Androgens; Animal Feed; Body Weight; Estrogens; Food Additives; Food Contamination; Hormones; Meat; Methylthiouracil; Progestins

Topics: Animals; Body Weight; Creatinine; Diet; Diuresis; Lithium; Male; Methylthiouracil; Rats; Sodium Chloride; Tannins; Time Factors; Vasopressins; Water; Water Deprivation

Topics: Alanine Transaminase; Animals; Arginase; Aspartate Aminotransferases; Body Weight; Dietary Proteins; Leucyl Aminopeptidase; Male; Methylthiouracil; Swine; Thiocyanates; Thyroid Gland; Thyroxine; Urea

Topics: Animals; Animals, Newborn; Axons; Body Weight; Cell Count; Cell Membrane; Geniculate Bodies; Histological Techniques; Hypothyroidism; Iodine Isotopes; Methylthiouracil; Microscopy, Electron; Nerve Endings; Neurons; Organ Size; Rats; Staining and Labeling; Synapses; Visual Cortex

Topics: Adrenal Glands; Adrenocorticotropic Hormone; Aminoglutethimide; Aniline Compounds; Animals; Anticonvulsants; Body Weight; Cholesterol; Chromatography, Thin Layer; Fatty Acids; Fatty Acids, Nonesterified; Female; Lipids; Methylthiouracil; Pyridones; Rats; Stimulation, Chemical; Triglycerides

Topics: Alkaloids; Animals; Body Weight; Iodine; Male; Methylthiouracil; Rats; Salivary Glands; Thyroid Gland; 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: Alkaline Phosphatase; Animals; Body Weight; Columbidae; Drug Synergism; Erythrocyte Count; Erythrocytes; Hematocrit; Hemoglobinometry; Hypophysectomy; Methylthiouracil; Prolactin; Thyroid Gland; Thyroxine

Topics: Adrenal Glands; Adrenocortical Hyperfunction; Adrenocorticotropic Hormone; Aminoglutethimide; Aniline Compounds; Animals; Anticonvulsants; Body Weight; Cricetinae; Drug Synergism; Female; Hyperthyroidism; Hypertrophy; Male; Methylthiouracil; Organ Size; Ovarian Diseases; Ovary; Pituitary Gland; Pyridones; Rats; Testicular Diseases; Thyroid Gland; Thyroid Hormones; Thyroidectomy; Uterus

Topics: Animals; Body Weight; Bone and Bones; Goiter; Keratosis; Liver; Methylthiouracil; Swine; Swine Diseases; Thyroid Gland; Zinc

Topics: Age Factors; Animals; Body Weight; Chickens; Meat; Methylthiouracil; Water

Topics: Animals; Body Weight; Chromatography; Iodine; Methylthiouracil; Organ Size; Swine; Thyroglobulin; Thyroid Gland

Topics: Adolescent; Adult; Basal Metabolism; Body Weight; Female; Heart Rate; Humans; Iodine; Iodoproteins; Leukocyte Count; Male; Methylthiouracil; Middle Aged; Thyroid Gland

Topics: Animal Feed; Animals; Body Weight; Cattle; Food Additives; Methylthiouracil

Topics: Adrenal Glands; Animals; Antithyroid Agents; Body Weight; Erythromycin; Hyperthyroidism; Male; Methylthiouracil; Organ Size; Rabbits; Rats; Thyroid Gland; Thyroid Hormones

Topics: Acetylcholinesterase; Acid Phosphatase; Adrenalectomy; Adrenocorticotropic Hormone; Animals; Body Weight; Cortisone; Dihydrolipoamide Dehydrogenase; Histocytochemistry; Hypertension; Hypothalamus; Iodine Isotopes; Male; Methylthiouracil; Monoamine Oxidase; NAD; Organ Size; Rats; Thyroid Hormones; Thyroidectomy

Topics: Animals; Body Weight; Diabetes Mellitus, Experimental; Diiodotyrosine; Drug Synergism; Hydroxypropiophenone; Methylthiouracil; Oxygen Consumption; Rats

Topics: Animals; Blood Proteins; Body Weight; Erythrocytes; Estradiol; Goiter; Male; Methyltestosterone; Methylthiouracil; Organ Size; Rats; Seminal Vesicles; Testosterone; Thyroid Gland; Thyroxine

Topics: Adrenal Medulla; Adrenocorticotropic Hormone; Arginine Vasopressin; Body Weight; Cold Temperature; Epinephrine; Guanethidine; Hypophysectomy; Iodine Isotopes; Methylthiouracil; Pharmacology; Phenoxybenzamine; Rats; Research; Tannins; Thyroid Function Tests; Thyroid Gland; Thyrotropin; Thyrotropin-Releasing Hormone; Vasopressins

Topics: Body Weight; Body Weights and Measures; Diiodotyrosine; Metabolism; Methylthiouracil; Pharmacology; Rats; Research; Thyroxine; Triiodothyronine; Tyrosine

Topics: Body Weight; Body Weights and Measures; Environment; Humidity; Metabolism; Methylthiouracil; Pharmacology; Rats; Research; Stress, Physiological; Temperature; Thyronines; Thyroxine; Triiodothyronine