methylthiouracil and Hypothyroidism

Caveolins modulate signaling pathways involved in cardiac development. Caveolin-1 exists in two isoforms: the beta-isoform derivates from an alternative translational start site that creates a protein truncated by 31 amino acids, mainly expressed in endothelial cells, whereas caveolin-3 is present in muscle cells. Our aim was to define caveolin distribution and expression during cardiac postnatal development using immunofluorescence and Western blotting. Caveolin-3 sarcolemmal labeling appeared as dotted lines from days 1 to 5 and as continuous lines after 14 days of age. Caveolin-3 expression, low at birth, increased (4-fold) to reach a maximum (P < 0.05) by day 5 and then decreased to stabilize in adults. Total caveolin-1 and its alpha-isoform were codistributed at birth in endothelial and smooth muscle cells; afterward, only the caveolin-1alpha labeling became limited to endothelium. Quantitative analysis indicated a similar temporal pattern of both total caveolin-1 and caveolin-1alpha expression, suggesting that caveolin-1alpha and -1beta are coregulated; the caveolin-1alpha levels increased fourfold by day 5 to reach a maximum by day 14 (P < 0.05). Tyrosine-14-caveolin-1 phosphorylation, low at birth, increased suddenly around day 14 (8-fold vs. day 1) and returning afterward to basal level. Because the T3/T4 level is maximal by day 14, caveolin-1 expression/phosphorylation profiles were analyzed in hypothyroid heart. The levels of caveolin-1alpha and consequently tyrosine-14-caveolin-1 phosphorylation, but not that of caveolin-3, decreased (50%) in hypothyroid 14-day-old rats. Our data demonstrate that, during postnatal cardiac growth, 1) caveolins are distinctly regulated, and 2) thyroid hormones are involved in caveolin-1alpha expression.

Topics: Adaptation, Physiological; Aging; Animals; Animals, Newborn; Caveolins; Gene Expression Regulation; Heart; Hypothyroidism; Methylthiouracil; Myocardium; Rats; Rats, Wistar; Thyroid Hormones; Tissue Distribution

The postnatal development of rat microglia is marked by an important increase in the number of microglial cells and the growth of their ramified processes. We studied the role of thyroid hormone in microglial development. The distribution and morphology of microglial cells stained with isolectin B4 or monoclonal antibody ED1 were analyzed in cortical and subcortical forebrain regions of developing rats rendered hypothyroid by prenatal and postnatal treatment with methyl-thiouracil. Microglial processes were markedly less abundant in hypothyroid pups than in age-matched normal animals, from postnatal day 4 up to the end of the third postnatal week of life. A delay in process extension and a decrease in the density of microglial cell bodies, as shown by cell counts in the developing cingulate cortex of normal and hypothyroid animals, were responsible for these differences. Conversely, neonatal rat hyperthyroidism, induced by daily injections of 3,5,3'-triiodothyronine (T3), accelerated the extension of microglial processes and increased the density of cortical microglial cell bodies above physiological levels during the first postnatal week of life. Reverse transcription-PCR and immunological analyses indicated that cultured cortical ameboid microglial cells expressed the alpha1 and beta1 isoforms of nuclear thyroid hormone receptors. Consistent with the trophic and morphogenetic effects of thyroid hormone observed in situ, T3 favored the survival of cultured purified microglial cells and the growth of their processes. These results demonstrate that thyroid hormone promotes the growth and morphological differentiation of microglia during development.

Topics: Animals; Brain; Cell Count; Cell Division; Cell Survival; Cells, Cultured; Female; Hyperthyroidism; Hypothyroidism; Iodine; Methylthiouracil; Microglia; Pregnancy; Prenatal Exposure Delayed Effects; Rats; Rats, Wistar; Receptors, Thyroid Hormone; Reverse Transcriptase Polymerase Chain Reaction; Thyroid Hormones; Triiodothyronine

During muscle development, an isozymic transition of the glycolytic enzyme enolase occurs from the embryonic and ubiquitous alphaalpha-isoform to the muscle-specific betabeta-isoform. Here, we demonstrate a stimulatory role of thyroid hormones on these two enolase genes during rat development in hindlimb muscles and an inhibitory effect on the muscle-specific enolase gene in cardiac muscle. In hindlimb muscles the ubiquitous alpha-transcript level is diminished by hypothyroidism, starting at birth. On the contrary, the more abundant muscle-specific beta-transcript is insensitive to hypothyroidism before establishment of the functional diversification of fibers and is greatly decreased thereafter. Our data support the hypothesis of a role of thyroid hormones in coordinating the expressions of contractile proteins and metabolic enzymes during muscle development. The subcellular localization of isoenolases, established here, is not modified by hypothyroidism. Our results underline the specificity of action of thyroid hormones, which modulate differentially two isozymes in the same muscle and regulate, in opposite directions, the expression of the same gene in two different muscles.

Topics: Animals; Gene Expression Regulation, Enzymologic; Heart; Hypothyroidism; Isoenzymes; Methylthiouracil; Muscle Development; Muscle, Skeletal; Myocardium; Myosin Heavy Chains; Phosphopyruvate Hydratase; Rats; Rats, Wistar; RNA, Messenger; Thyroid Hormones; Triiodothyronine

The effect of hypothyroidism on adrenals and gonads in adult female rats was investigated throughout the estrous cycle. Hypothyroidism was induced by administration of 4-Methyl-2-Thiouracil (Thiouracil) in the drinking water. The weight of ovaries and adrenals, and the plasma levels of corticosterone decreased in hypothyroid rats as compared with euthyroid rats throughout the estrous cycle. Hypothyroidism resulted in decreased concentrations of plasma LH on the day of diestrus and proestrus, whereas the plasma concentrations of prolactin and progesterone increased as compared with euthyroid rats. The weight of uteri and plasma concentrations of estradiol decreased during the day of diestrus and proestrus in hypothyroid rats as compared with euthyroid rats. To further clarify the dysfunction of hypothalamo-hypophysial-adrenal axis in hypothyroid rats, animals were stressed by immobilization for 3 hr. In hypothyroid rats, a marked increase in plasma levels of ACTH in response to immobilization stress was observed compared to euthyroid control, whereas increases in plasma concentrations of corticosterone were much smaller in hypothyroid than euthyroid rats. These results clearly indicate that hypothyroidism causes both gonadal and adrenal disturbances in adult female rats. The increased concentrations of plasma progesterone may be due to hypersecretion of prolactin during the day of proestrus and estrus, which in turn result in disruption of the estrous cycle.

Topics: Adrenal Glands; Adrenocorticotropic Hormone; Animals; Corticosterone; Estrus; Female; Hypothalamo-Hypophyseal System; Hypothyroidism; Luteinizing Hormone; Methylthiouracil; Organ Size; Ovary; Pituitary-Adrenal System; Progesterone; Prolactin; Rats; Rats, Wistar; Reference Values; Thyroid Hormones; Uterus

1. Male Sprague-Dawley rats were made either hyper- or hypothyroid with thyroxine or 4-methyl-2-thiouracil, respectively. Bronchial smooth muscle (BSM) contractility and lung cyclic adenosine 3',5'-monophosphate (cAMP) content were measured in both conditions. 2. Bronchial smooth muscle contractility was significantly weaker in hyperthyroid rats, while the BSM contractility of hypothyroid rats was the same as controls. 3. The cAMP content of hyperthyroid rat lungs was similar to controls but was decreased in hypothyroid rats. 4. These studies demonstrated that both the hyper- and hypothyroid states affect respiration, although the mechanisms involved with different for each condition.

Topics: Animals; Bronchi; Cyclic AMP; Hyperthyroidism; Hypothyroidism; Lung; Male; Methylthiouracil; Muscle Contraction; Muscle, Smooth; Rats; Rats, Sprague-Dawley; Thyroxine

Welsh Mountain ewes (n = 6) were rendered hypothyroid by daily treatment with methylthiouracil (35 mg/kg), beginning in early August and ending in late February. Plasma thyroxine levels were reduced by mid-September to about 33% of those in untreated ewes (n = 6). The two groups of ewes were held under natural daylengths until 5 October, then on 12 h light: 12 h darkness (12L:12D) until 28 February when the photoperiod was reduced to 8L:16D. The onset of reproductive cyclicity in October was similar in both groups of ewes but the end of the reproductive period occurred later (P less than 0.05) in the hypothyroid ewes (29 January +/- 7 days (S.E.M.] than in the untreated controls (6 January +/- 7 days). As a result, the duration of the seasonal reproductive period was significantly (P less than 0.05) longer in the hypothyroid (122 +/- 9 days) than in the untreated ewes (91 +/- 10 days). The number of oestrous cycles (duration 15.4 and 15.7 days in the hypothyroid and untreated ewes respectively) was 7.0 +/- 0.6 in the hypothyroid ewes and 5.0 +/- 0.5 (P less than 0.05) in the normal ewes. Reducing the photo-period overcame the reproductive refractoriness and anoestrus in both groups, the hypothyroid ewes beginning to cycle on 13 April (+/- 0.5 days) after an anoestrous period of 72.8 +/- 7.1 days. The untreated ewes began to cycle 2 weeks later on 26 April (+/- 1.7 days) after an anoestrous period of 112.0 +/- 8.5 days (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Analysis of Variance; Anestrus; Animals; Estrus; Estrus Synchronization; Female; Hypothyroidism; Light; Methylthiouracil; Progesterone; Seasons; Sheep; Sheep Diseases; Thyroidectomy; Thyroxine

Since stimulation of heart hypertrophy by pressure overload was previously shown to be accompanied by a densification of microtubule network in rat heart myocytes, we verified that similar process occurred during postnatal growth in euthyroid rats and in hypothyroid rats whose growth was stimulated by 4 micrograms/day L-thyroxine (T4). For this purpose, tubulin, the constituent protein of microtubules, was immunolabeled in myocytes isolated at various times after birth. Myocyte hypertrophy was evaluated by myocyte size, the number of nuclei per cell and isomyosin expression. In hypothyroid rats, the microtubule network, which was underdeveloped, was most dense around the nucleus. During the phase of fast myocyte hypertrophy observed in euthyroid rats during late postnatal development and in hypothyroid rats after T4 administration, transient microtubule densification occurred in a myocyte subpopulation in which size was mainly determined by the rate of myocyte hypertrophy. The densification process and its kinetics resembled those observed when heart hypertrophy was induced by pressure overload. It is concluded that in rat heart myocytes undergoing hypertrophy, microtubule densification might be related to fast sarcomerogenesis, whether the stimulus is mechanical (e.g., pressure overload) or hormonal (e.g., T4).

Topics: Aging; Animals; Cardiomegaly; Female; Fluorescent Antibody Technique; Heart; Hypothyroidism; In Vitro Techniques; Methylthiouracil; Microtubules; Myocardium; Pregnancy; Rats; Rats, Inbred Strains; Thyroxine

The postnatal development of the global volume of the subcommissural organ (SCO) and of the karyometric changes of the ependymocytes in the SCO and the adjacent ventricle is studied in male albino mice aged from 25 to 160 days, and in a hypothyroid group treated with propylthiouracil with and without interruption of the treatment at 35 days. Hypothyroidism produces a decrease of the global volume of the SCO and of the nuclear size of the ependymocytes in the SCO and the adjacent ventricle.

Topics: Animals; Cell Nucleus; Ependyma; Hypothyroidism; Male; Methylthiouracil; Mice; Neurosecretory Systems; Subcommissural Organ

Interference microscopy was used to measure dry mass of pyramidal neurones of hippocampal CA1 and CA3 areas in control and hypothyroid rats aged 14 and 21 days and 2 months. Hypothyrosis was induced in the newborn by intraperitoneal injection of methylthiouracil to the lactating female during the lactation period (for 1 month). Hypothyrosis caused a considerable retardation of the animals' growth. A significant decrease in he concentration of dry substances was detected only in the cytoplasm of Ca1 area neurones in the group of 2-month-old hypothyroid animals. The measurements have demonstrated that hypothyrosis gives rise to pronounced retardation of the neuronal build-up and accumulation of protein products in the cytoplasma of hippocampal pyramidal cells in all the animal groups examined. The size and dry weight of neuronal nuclei of both the hyppocampal areas substantially diminish in the group of 2-month-old hypothyroid animals.

Topics: Aging; Animals; Female; Hippocampus; Hypothyroidism; Methylthiouracil; Microscopy, Interference; Nerve Tissue Proteins; Neurons; Rats; Rats, Inbred Strains

The studies were made in order to estimate the rate of tissue protein synthesis in euthyroid, hyperthyroid and hypothyroid rats (110 g body weight). Hyperthyroidism was simulated by daily oral application of 4,44 micrograms thyroxine (T4) and 0,89 micrograms triiodothyronine (T3)/100 g body weight. Hypothyroidism was induced by oral application of 17,8 mg of methylthiouracil (MTU) per day and 100 g body weight. In both cases the treatment lasted for 7 days. The concentration of both hormones in blood serum was twice that of the control group in the T3 + T4 treated group. The MTU application produced a decrease in T3 and T4 concentration to levels below the lower detection limits of the methods used. The fractional rate of tissue protein synthesis was estimated using the constant intravenous infusion technique with L-14C-leucine and L-14C-lysine simultaneously. The range of the fractional rate of protein synthesis was found to be higher in hyperthyroid than in control animals in all organs under study (liver, small intestine, large intestine, gastrocnemius muscle and pancreas). Protein synthesis was stimulated to the greatest extent in muscle (4,5--5,1% . d-1 in controls vs, 5,5--6,7% . d-1 in hyperthyroid animals). The influence of hypothyroidism on the rate of protein synthesis was uncertain.

Topics: Animals; Hyperthyroidism; Hypothyroidism; Leucine; Lysine; Male; Methylthiouracil; Protein Biosynthesis; Rats; Thyroxine; Tissue Distribution; Triiodothyronine

Male white Wistar-rats are treated alone and in combination with methylthiouracil and lead acetate. The histologic-cytological and the caryometrical results and the weights of the thyroids show an increase thyroid activity following as well methylthiouracil as lead application. The thyroxin-iodine blood level and the cholesterol blood level are altered. The strongest enhancement of the activity is obtained in the combination group methylthiouracil plus lead acetate. More slow activations are present in the groups with singular application methylthiouracil or lead acetate application. The findings are caused by encymatic inhibition of the applicated substances.

Topics: Animals; Cell Nucleus; Hypothyroidism; Karyometry; Lead; Lead Poisoning; Male; Methylthiouracil; Organometallic Compounds; Rats; Rats, Inbred Strains; Thyroid Gland

In a chronic experiment, male white Wistar-rats are treated with methylthriouracil and lead acetate alone and in combination. Additionally the animals of 2 groups are thyroidectomised. The pineal glands are investigated gravimetrically, histologic-cytologically, and caryometrically. The rank correlation analysis of the gravimetrical and caryometrical results proves the significance. The results show a decrease pineal activity following as well methylthiouracil application as thyroidectomy. The strongest decrease of the activity in the combination group thyroidectomy plus lead acetate is obtained. Changes in the pineal glands are not obtained neither after lead acetate application alone nor in combination with methylthiouracil. The results allow to draw the following conclusion: Lead acetate reduced the effect of methylthiouracil, in our opinion a hypothetic methylthiouracil-lead-compound is built. This interpretation is supported by the persistent effect of thyroidectomy whenever lead acetate is combined with thyroidectomy. These results and the results of the suprarenal cortex (Peschke et al. 1981) show clearly, that there is an interference between the methylthiouracil and lead acetate. Under these experimental conditions, one can speak of an ineffectual methylthiouracil-lead-compound.

Topics: Animals; Cell Nucleus; Hypothyroidism; Lead Poisoning; Male; Methylthiouracil; Pineal Gland; Rats; Rats, Inbred Strains

In a chronic experiment, male Wistar-rats were treated alone and in combination with methylthiouracil and lead acetate. Additionally, the animals of 2 groups were thyroidectomised. The suprarenal organs were investigated gravimetrically. Histologic-cytological and caryometrical investigations were made on the suprarenal cortex. After lead acetate application in the cortex, strong histologic-cytological alterations were obtained. There are marked damages especially in the zona fasciculata; a great number of pycnotic nuclei, a small subcapsular blastem, and a spreading out of the zona reticularis are observed. The size of nuclei is significantly diminished. These results indicated a regressive transformation and a toxic effect is discussed. After application of methylthiouracil or thyroidectomy, a regression transformation is found too. Cellular degenerations in all zones of the cortex are rarely or not obtained. As well methylthiourail as thyroidectomy diminish the weights of suprarenal organs high significantly. These results are not found after combined application of methylthiouracil and lead acetate. Methylthiouracil reduced the effect of lead acetate. The results allow to draw the following conclusion: In our opinion, a hypothetic methylthiouracil-lead-compound is built. This interpretation is supported by the persistent effect of lead acetate whenever lead acetate is combined with thyroidectomy.

Topics: Adrenal Cortex; Animals; Hypothyroidism; Lead Poisoning; Male; Methylthiouracil; Rats; Rats, Inbred Strains

Topics: Animals; Hypothyroidism; Kinetics; Male; Methylthiouracil; Pituitary Gland; Rats; Thyroid Gland; Thyrotropin

1. A trace amount of glucose labelled with 14C uniformly and with 3H at position 2, 3 or 6 was injected intravenously into starved rats to measure the turnover rate of blood glucose. 2. Reliable estimates were made based on the semilogarithmic plot of specific radioactivity of the glucose contained in whole blood samples taken from the tail vein. 3. Glucose turned over more rapidly in hyperthyroid and more slowly in hypothyroid than in euthyroid rats. The percentage contribution of glucose recycling (determined from the difference in replacement rates between [U-14C]glucose and [6-3H]glucose) to the glucose utilization increased on induction of hyperthyroidism. 4. Futile cycles between glucose and glucose 6-phosphate (determined from the difference between replacement rates of [2-3H]glucose and [6-3H]glucose) were activated and inactivated by induction of hyperthyroid and hypothyroid states respectively. 5. The hepatic content of glycogen was much lower in hyper- and hypo-thyroid than in euthyroid rats. The enhanced glucose production in hyperthyroid rats resulted from not only activationof hepatic gluconeogenesis but also diversion of the final product of gluconeogenesis from liver glycogen to blood glucose. In hypothyroidism, the inhibition of gluconeogensis led to suppression of both glucose production and glycogenesis in the liver.

Topics: Animals; Blood Glucose; Carbon Radioisotopes; Glucose; Hyperthyroidism; Hypothyroidism; Kinetics; Liver; Liver Glycogen; Male; Methods; Methylthiouracil; Rats; Thyroxine; Tritium

A new model has been used to evaluate the effects of thyroid hormones on brain development. This model is based on the assumption that the major effect of thyroid hormones is in regulating the rate of neurite growth of the rat brain at early stages of postnatal development. Microtubules were chosen as markers of neurite growth. We tested, therefore, whether the rate of microtubule assembly in vitro is under thyroid hormone control. The following results were obtained: The rate of tubulin assembly into microtubules in vitro seems to be thyroid hormone dependent: (a) in 15-day-old hypothyroid rats the rates of tubulin assembly in vitro are low, comparable to those levels found in normal rats on day 3; (b) normal rates of assembly in vitro are restored upon addition of very small amounts of microtubule fragments which act as nucleating centers in the process of microtubule formation; (c) addition of microtubule-associated proteins to a hypothyroid preparation restores maximal assembly rates; similar results were obtained on adding one of the microtubule-associated proteins (purified tau protein); (d) physiological amounts of thyroid hormones completely restore normal assembly rates provided that they are administered very early after birth; (e) the ability of tubulin to assemble maximally does not seem to be permanently impaired, since normal assembly rates are spontaneously restored when hypothyroidism is maintained until an adult stage; (f) normal microtubule assembly is observed when hypothyroidism is produced at an adult stage. The model which may be constructed from these results implies that thyroid hormones are required briefly after birth to accelerate the rate of microtubule assembly thus allowing intensive neurite growth during the critical period of brain development.

Topics: Aging; Animals; Brain; Female; Hypothyroidism; Kinetics; Methylthiouracil; Microtubules; Pregnancy; Rats; Thyroid Hormones; Thyroxine; Tubulin

Patients treated with 10 mCi of I-131 for toxic diffuse goiter in the period January 1974--June 1976 were evaluated for development of hypothyroidism. Fifty percent were hypothyroid within 3 mo and 69% within 1 yr of treatment. Our data suggest that there is a higher incidence of hypothyroidism after standard doses of I-131 in the 1970s as contrasted with treatment groups in the 1950s and 1960s. The pathophysiology of this increased incidence is not known with certainty; however, infrequent use of thionamide medication, together with recent increases in dietary iodine, may render the gland more radiosensitive.

Topics: Adolescent; Adult; Female; Humans; Hyperthyroidism; Hypothyroidism; Iodine Radioisotopes; Male; Methylthiouracil; Middle Aged; Radiotherapy; Retrospective Studies; Time Factors

Total body fat content was determined in growing normal male Wistar rats and hypothyroidized animals 7 weeks after feeding with Methimazol (group MMI-HT), Methyl-thiouracil (group MTU-HT), and performance of radiothyroidectomy by 131-iodine (group R-HT), respectively. At the end of experiments there was an extreme hypothyroid state in all treated groups, verified by external signs, growth kinetics, serum cholesterol estimation and evaluation of the iodothyrosine pattern of the thyroid glands. Changed body composition resulted in all HT-groups from significant increase of total body fat content. The relation of constituents fat : protein : water of 1 : 2 : 6 in the KT-group was changed into 1 : 1 : 3 in the HT-groups. No differences were found between the different HT-groups. Our findings are in good agreement with altered metabolism of plasma lipids described by other authors showing the existence of a highly disturbed lipid metabolism in thyroid hormone deficiency.

Topics: Animals; Body Composition; Cholesterol; Hypothyroidism; Iodine Radioisotopes; Lipid Metabolism; Male; Methimazole; Methylthiouracil; Rats

Topics: Age Factors; Animals; Brain; Glycoproteins; Hypothyroidism; Methylthiouracil; Microtubules; Rats; Thyroxine; Tubulin

Extreme rat hypothyreosis of identical degree was induced by radiothyroidectomy (group R-HT) and feeding of thyreostatics (groups MTU-HT and MMI-HT). External signs, growth kinetics, serum cholesterol, thyroid weight, and the iodothyrosine pattern of the thyroid glands served as references for the quality of the hypothyreotic state. Determinations of following changes (all changes significant for p less than 0.001): 1. Higher total serum protein levels in hypothyreotic rats 4 and 7 weeks after beginning the experiemnts as compared to the controls (KT). 2. After 4 weeks the relative albumin content was diminished, the relative gamma-globulin content was elevated as compared to the KT. The absolute values of albumines did not change, alpha-1-globuline and gamma-globuline contents were increased in all hypothyreotic groups. 3. After 7 weeks normal albumine values, increase of the relative and absolute alpha-1-globuline content, and decrease of the relative beta-globuline concentrations were measured. Elevated gamma-globulins were found in MMI-HT and R-HT only, and an increased absolute albumine content in MTU-HT alone. The results confirm both hyperproteinemia and dysproteinemia as characteristics of the rat hypothyreotic state. Dynamic changes of absolute and relative contents of different serum protein fractions are demonstrated in relation to the duration of hypothyreosis. This fact can possibly explain contradictory findings on type of dysproteinemia by several authors.

Topics: Animals; Blood Proteins; Hypothyroidism; Kinetics; Male; Methylthiouracil; Rats; Serum Albumin; Thyroid Gland; Thyroidectomy

Activity of alkaline and acid phosphatase was determined by the method of Bodansky in blood serum, homogenates of liver, kidney, lung, brain, liver mitochondrial fraction of normal, methylthiouracil-induced hypothyroid, and Thyroideum-induced hyperthyroid rats. The following results were obtained: an increase in both enzymes in all studied materials in hyperthyroidism, and a decrease in most of the studied materials in hypothyroidism.

Topics: Acid Phosphatase; Alkaline Phosphatase; Animals; Brain; Hyperthyroidism; Hypothyroidism; Lung; Male; Methylthiouracil; Mitochondria, Liver; Rats; Thyroid Hormones

In rats hypothyroidized with methylthiouracil (MTU), methimazol (MMI), or radiothyroidectomy, the extent of deiodination for L-diiodotyrosine (L-DIT) and L-thyroxine (L-T4) was investigated in homogenate supernatants of liver and kidney. Deiodination in liver and kidney for DIT is twice as high as for T4, but the kidney allows only 25% of the liver deiodination activity both for DIT and T4. In the livers of all hypothyroid animals, iodide splitting both from DIT and T4 is highly significantly reduced by one-half compared with controls. In the kidney of all hypothyroid animals, the DIT deiodination is highly significantly lowered in comparison with controls; the T4 deiodination is significantly reduced only in animals treated with MTU and MMI, and is not significantly enhanced in radiothyroidectomized rats. Thus, there is no difference between MTU and MMI in the extent of deiodination for DIT and T4 in the homogenate supernatants of rat liver or kidney.

Topics: Animals; Binding Sites; Diiodotyrosine; Hypothyroidism; Iodine; Kidney; Liver; Male; Methimazole; Methylthiouracil; Radiation Effects; Rats; Thyroid Gland; Thyroidectomy; Thyroxine

In homogenate supernatants of kidneys of male rats the extent of deiodination of L-diiodotyrosine (L-DJT) and L-thyroxine (L-T4) was investigated in dependence on the thyroid function (hypo- and hyperthyroidized) and also in dependence on age. In rats hypothyroidized by loading with Methylthiouracil (MTU) or Methimazol (MMI) the deiodination for L-DJT and L-T4 was significantly reduced, in rats loaded with 40 mug T4 sc. for 10 days, the deiodination was significantly enhanced compared with untreated control animals. With advancing age (6 weeks, 3 or 12 month) the deiodination activity is highly significantly reduced. The results underline relations between thyroid gland function and deiodination activity in kidney.

Topics: Age Factors; Animals; Diiodotyrosine; Hyperthyroidism; Hypothyroidism; Iodine; Kidney; Male; Methimazole; Methylthiouracil; Monoiodotyrosine; Rats; Thyroid Diseases; Thyroid Hormones; Thyroxine; Triiodothyronine

The comparative study of the in vivo synthesis of thyroglobulin and proteins other than thyroglobulin was carried out in thyroid glands from animals submitted to different levels of TSH stimulation. The different levels of hormonal stimulation modify neither the rate of labeling after injection of the isotope, nor the level of the free labeled amino acid in the glands (percent of the total uptake), but they have a very significant effect on the level of incorporation of the isotope into total proteins. In hypostimulated thyroids the total protein synthesis is very much reduced, while in hyperstimulated glands it is significantly increased. In both hyper- and hypostimulated animals, the proportion of radioactivity bound to the particulate protein fraction is higher than in control rats. However, the solubilization by digitonine of these proteins is lower in hypostimulated and higher in hyperstimulated animals than in controls. Thyroglobulin synthesis is significantly modified qualitatively and quantitatively in both hypo- and hyperstimulated glands. Qualitative modifications are characterized by a changed ratio of 19 S/12 S molecules with respect to the controls. This is probably caused by a more important dissociation of 19S molecules, due to the lower level of halogenation in both hypo- and MTU treated glands. The quantitative modifications of thyroglobulin synthesis, expressed either in absolute values (DPM/mg of tissue), or relatively to the total proteins (percent of total newly formed proteins), are characterized by a very important inhibition of this synthesis in hypostimulated glands, and its stimulation in glands chronically submitted to the TSH action. The modifications of synthesis observed for the proteins other than thyroglobulin are less significant in both types of treated glands than are those observed for thyroglobulin. The level of hormonal stimulation has no effect on the distribution of these proteins between soluble and the particulate fraction, but seems to have a slight effect on the solubilization of the latter ones. Comparative evaluation of the TSH effect on the synthesis of different thyroidal proteins shows that it has a much more specific and significant action on thyroglobulin than on other proteins. The differential effect of TSH on the synthesis of thyroglobulin and proteins other than thyroglobulin suggests that different mechanisms may exist by which TSH regulates the synthesis of these two types of proteins.

Topics: Animals; Digitonin; Hyperthyroidism; Hypophysectomy; Hypothyroidism; Kinetics; Methylthiouracil; Protein Biosynthesis; Rats; Thyroglobulin; Thyroid Gland; Thyroxine

Topics: Animals; Blood Glucose; Disease Models, Animal; Gluconeogenesis; Glucose Tolerance Test; Hyperthyroidism; Hypothyroidism; Male; Methimazole; Methylthiouracil; Rats; Thyroid Gland; Thyroxine

Topics: Animals; Hypothyroidism; Lactates; Male; Methimazole; Methylthiouracil; Pyruvates; Rats; Thyroid Diseases; Thyroxine

Topics: Animals; Antithyroid Agents; Hyperthyroidism; Hypothyroidism; Male; Methylthiouracil; Neuraminic Acids; Rats; Thyroid Hormones; Thyroidectomy; Thyroxine; Triiodothyronine

Topics: Adolescent; Female; Goiter; Hemorrhage; Humans; Hyperthyroidism; Hypoparathyroidism; Hypothyroidism; Iodine; Methylthiouracil; Postoperative Care; Postoperative Complications; Potassium Iodide; Preoperative Care; Propylthiouracil; Thyroid Diseases; Thyroidectomy; Thyroiditis; Time Factors; Vocal Cord Paralysis

Topics: Animals; Brain Chemistry; Catecholamines; Hyperthyroidism; Hypothyroidism; Male; Methylthiouracil; Rats; Serotonin; Spectrometry, Fluorescence; Triiodothyronine

Topics: Alcohol Oxidoreductases; Animals; Ascorbic Acid; Carboxy-Lyases; Esterases; Glucuronates; Hypothyroidism; Ketones; Kidney; Lactones; Liver; Male; Methylthiouracil; Rats; Sugar Acids

Topics: Adrenal Glands; Animals; Corticosterone; Growth Hormone; Hypothyroidism; Male; Methylthiouracil; Parathyroid Glands; Rats; Thyroid Hormones; Thyroidectomy; Thyroxine

Topics: Adrenergic beta-Antagonists; Antithyroid Agents; Carbimazole; Chemical Phenomena; Chemistry; Humans; Hyperthyroidism; Hypothyroidism; Imidazoles; Iodine Isotopes; Methimazole; Methylthiouracil; Myocardial Infarction; Perchlorates; Potassium; Potassium Iodide; Propranolol; Propylthiouracil; Psychotic Disorders; Thiourea; Thyroxine; Time Factors

Topics: Animals; Gastric Mucosa; Glycosaminoglycans; Histocytochemistry; Hyperthyroidism; Hypothyroidism; Methylthiouracil; Rats; Thyroid Hormones; Thyroidectomy

Topics: Acid Phosphatase; Adenosine Triphosphatases; Alkaline Phosphatase; Animals; Histocytochemistry; Hyperthyroidism; Hypothyroidism; Methylthiouracil; Rats; Stomach

Topics: Animals; Antigens; Brucella; Brucellosis; Guinea Pigs; Hypersensitivity, Delayed; Hyperthyroidism; Hypothyroidism; Leukocyte Count; Lymphocytes; Methylthiouracil; Skin Tests; Thyroid Hormones; Thyroidectomy

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: Animals; Hyperthyroidism; Hypothyroidism; Immobilization; Methylthiouracil; Mice; Stomach Ulcer; Stress, Physiological; Thyroid Gland; Thyroidectomy; Thyroxine

Topics: Animals; Cell Nucleolus; Cell Nucleus; Cerebral Cortex; Endoplasmic Reticulum; Hypothyroidism; Methylthiouracil; Microscopy, Electron; Neurons; Rats; Synapses

Topics: Adolescent; Child; Child, Preschool; Diagnosis, Differential; Germany, East; Humans; Hyperthyroidism; Hypothyroidism; Infant; Infant, Newborn; Methimazole; Methylthiouracil; Thyroid Diseases; Thyroid Hormones; Thyroidectomy

Topics: Adenocarcinoma; Animals; Basophils; Female; Hypothyroidism; Liver Neoplasms; Mammary Neoplasms, Experimental; Methylthiouracil; Neoplasms, Experimental; Ovarian Neoplasms; Pituitary Gland; Rats; Thyroid Neoplasms; Thyroidectomy

Topics: Adolescent; Animals; Brain Diseases; Cerebellar Nuclei; Congenital Hypothyroidism; Diencephalon; Female; Humans; Hypothyroidism; Karyometry; Mesencephalon; Methylthiouracil; Myxedema; Rats; Thyroid Gland; Thyroid Hormones; Thyroxine; Triiodothyronine

Topics: Albumins; Animals; Beta-Globulins; Cattle; Electrophoresis; Female; gamma-Globulins; Hyperthyroidism; Hypothyroidism; Lactoglobulins; Methylthiouracil; Milk; Thyroxine

Topics: Animals; Cerebral Cortex; Hyperthyroidism; Hypothyroidism; Methylthiouracil; Organ Size; Rats; Thyroxine

Topics: Animals; Hyperthyroidism; Hypothyroidism; Leukocytes; Methylthiouracil; Peritonitis; Phagocytosis; Rabbits; Thyroid Hormones; Vitamin B 12

Topics: Allantoin; Animals; Hyperthyroidism; Hypothyroidism; Methylthiouracil; Purines; Rats; Thyroid Hormones; Thyroxine; Uric Acid

Topics: Amphetamine; Animals; Appetite; Blood Glucose; Body Temperature; Fatty Acids, Nonesterified; Fever; Hypothyroidism; Male; Methylthiouracil; Motor Activity; Rats

Topics: Animals; Brain; Conditioning, Classical; Hyperthyroidism; Hypothyroidism; Methylthiouracil; Mice; Motor Activity; Thyroid Hormones

Topics: Fibrinogen; Fibrinolysin; Fibrinolysis; Humans; Hyperthyroidism; Hypothyroidism; Methylthiouracil; Plasminogen; Thyroid Function Tests; Thyroid Gland; Thyroxine

Topics: Animals; Cerebral Cortex; Electroencephalography; Hippocampus; Hypothyroidism; Iodine Isotopes; Methylthiouracil; Nicotine; Pentylenetetrazole; Perchlorates; Rabbits; Seizures; Thyroid Gland

Topics: Animals; Connective Tissue; Hyperthyroidism; Hypothyroidism; Methylthiouracil; Muscle Denervation; Muscle Proteins; Myofibrils; Nitrogen; Rabbits; Rats; Sciatic Nerve; Solubility; Thyroid Hormones; Time Factors

Topics: Animals; Ascorbic Acid; Dermatologic Agents; Hypothyroidism; Male; Methylthiouracil; Mitochondria, Liver; Oxidative Phosphorylation; Rats; Tannins

Topics: Animals; Asphyxia; Diabetes Mellitus, Experimental; Female; Fetal Heart; Heart; Heart Defects, Congenital; Humans; Hyperthyroidism; Hypothyroidism; Methylthiouracil; Myocardial Infarction; Myocardium; Obstetric Labor Complications; Pregnancy; Pregnancy Complications; Rabbits; Radiation Effects; Thyroid Hormones

Topics: Achilles Tendon; Adult; Aged; Creatine Kinase; Female; Humans; Hyperthyroidism; Hypothyroidism; Iodine Radioisotopes; Male; Methylthiouracil; Middle Aged; Myxedema; Reflex, Abnormal; Thyroid Function Tests; Thyroxine

Topics: Animals; Cartilage; Epiphyses; Hyperthyroidism; Hypothyroidism; Male; Metacarpus; Methylthiouracil; Osteogenesis; Rats; Thyroxine

Topics: Adrenalectomy; Animals; Ascorbic Acid; Castration; Histocytochemistry; Hypothalamo-Hypophyseal System; Hypothalamus; Hypothyroidism; Methylthiouracil; Rats; Temporal Lobe

Topics: Animals; Animals, Newborn; Bone and Bones; Brain; Female; Fetus; Growth; Hypothyroidism; Liver; Maternal-Fetal Exchange; Methylthiouracil; Milk; Phosphates; Phospholipids; Pregnancy; Pregnancy, Animal; Rabbits

Topics: Animals; Animals, Newborn; Chorionic Gonadotropin; Female; Hypophysectomy; Hypothyroidism; Methylthiouracil; Organ Size; Ovary; Rats; Uterus

Topics: Adrenalectomy; Adrenocortical Hyperfunction; Amine Oxidase (Copper-Containing); Blood; Drug Tolerance; Histamine; Hydroxides; Hypothyroidism; Methylthiouracil; Mice; Research; Sodium Chloride; Thyroxine; Toxicology

Topics: Animals; Female; Humans; Hypothyroidism; Lagomorpha; Methylthiouracil; Muscle Proteins; Pharmacology; Pregnancy; Pregnancy, Animal; Rabbits; Research; Uterus

Topics: Blood Glucose; Carbohydrate Metabolism; Cholesterol; Dextrothyroxine; Hypothyroidism; Insulin; Lipid Metabolism; Metabolism; Methylthiouracil; Niacin; Nicotinic Acids; Pharmacology; Rats; Research; Thyroxine

Topics: Animals; Blood Protein Electrophoresis; Blood Proteins; Cattle; gamma-Globulins; Humans; Hypothyroidism; Methylthiouracil

Topics: Animals; Constipation; Diarrhea; Dogs; Gastric Juice; Hyperthyroidism; Hypothyroidism; Methylthiouracil; Pharmacology; Physiology; Research; Stomach; Thyroid Hormones

Topics: Animals; Chorionic Gonadotropin; Estrogens; Female; Gonadotropins; Gonadotropins, Equine; Horses; Humans; Hyperthyroidism; Hypophysectomy; Hypothyroidism; Methylthiouracil; Ovary; Pharmacology; Pregnancy; Rats; Research; Thyroid Hormones; Thyroidectomy; Thyroxine; Uterus

Topics: Chorionic Gonadotropin; Estrogens; Female; Gonadotropins; Humans; Hypophysectomy; Hypothyroidism; Methylthiouracil; Ovary; Thyroid Hormones; Uterus

Topics: Histological Techniques; Humans; Hypothyroidism; Iodine; Iodine Radioisotopes; Methylthiouracil; Thiouracil; Thyroid Function Tests; Thyroid Gland

Topics: Humans; Hypothyroidism; Iodides; Iodine; Methylthiouracil; Thiouracil

Topics: Animals; Food; Hypothyroidism; Metabolism; Methylthiouracil; Rats

Topics: Body Temperature; Body Temperature Regulation; Cold Temperature; Guinea Pigs; Hypothyroidism; Methylthiouracil; Thiouracil; Thyroid Gland; Viscera

Topics: Animals; Food; Gastrointestinal Tract; Hypothyroidism; Methylthiouracil; Nutritional Physiological Phenomena; Nutritional Sciences; Nutritional Status; Rats