Showing papers on "Propylthiouracil published in 1971"

Concentration of 35S-propylthiouracil by the thyroid gland and its relationship to anion trapping mechanism.

Abstract: Propylthiouracil is concentrated by the thyroid gland in rats and man. Four 35 S compounds were demonstrated in the rat and human thyroid by thin-layer chromatography: sulphate, intact propylthiouracil, an unknown metabolite X and origin 35 S activity which is protein bound. Unbound 35 S compounds in plasma include propylthiouracil, the glucuronide conjugate of PTU, sulphate, and X. The thyroid concentration rather than the plasma level of propylthiouracil determines the duration of inhibition of organic binding of iodine in the thyroid. The effect of perchlorate and iodide on the thyroid concentrating mechanism for 35 S-propylthiouracil and 125 I-iodide was studied. The level of perchlorate and iodide which almost completely blocked the concentration of 125 I-iodide also partially reduced the concentration of 35 S-propylthiouracil. Iodide but not perchlorate decreased the rate of metabolism of 35 S-propylthiouracil in the thyroid gland.

Functioning primary thyroid carcinoma and metastases producing hyperthyroidism.

Abstract: An unusual instance of hyperthyroidism due to primary and metastatic thyroid carcinoma is presented Radioactive iodine scanning showed predominant uptake in the tumor, confirmed by radioautography, with suppression of function in the remaining normal tissue During propylthiouracil treatment, the thyrotoxic state remitted while function of the previously suppressed normal tissue increased These findings implicated the tumor tissue as the cause of the patient's hyperthyroidism Though extremely rare, such cases emphasize the importance of careful observation of apparently benign hyperfunctioning nodules

Stimulatory and inhibitory action of estradiol on TSH secretion.

Abstract: Subcutaneous administration of low doses of estradiol benzoate (EB: 0.004, 0.016, 0.064, 0.256 txg daily, 9–11 days) to rats ovariectomized for 28–30 days resulted in stimulation or inhibition of pituitary-thyroid function. The relatively low dose of 0.064 /xg elevated pituitary and plasma TSH levels and induced thyroid hyperplasia. A higher dose level (.256 μg) inhibited TSH secretion by the pituitary and caused involution of the thyroid gland. The biphasic action of estradiol of TSH secretion was not attributable to alterations in the thyroxine (T4) binding capacity of the blood proteins. Resin uptake of radiothyroxine from plasma was significantly decreased in rats treated with propylthiouracil (PTU) or in animals subjected to thyroidectomy, ovariectomy and hypothalamic lesioning. The administration of EB to hypothyroid rats failed to influence appreciably T4 resin uptake from plasma. In contrast, a critical dose level of EB (.02 μg daily, 7–8 days) stimulated TSH secretion in thyroidectomized, ovariec...

TSH-Induced Appearance and Stimulation of Amine-Containing Mast Cells in the Mouse Thyroid

Abstract: Intra- and extrathyroidal mast cells in mice were located by their metachromasia and histochemically demonstrable 5-hydroxytryptamine (5-HT) and histamine content, and plasma TSH levels were determined by bioassay. Untreated mice had no detectable plasma TSH ( <0.1 mU/ml), and no or very few intrathyroidal mast cells, whereas numerous mast cells were found in adjacent tissues. During propylthiouracil (PTU) treatment, plasma TSH rose progressively (to 4.0 mU/ml at 4 weeks) and several amine-containing mast cells appeared in the thyroid. Concomitant administration of thyroid hormone prevented these effects, and withdrawal of PTU was followed by decreased plasma TSH levels and a disappearance of the thyroid mast cells. However, the content of amines and metachromatic material in thyroid mast cells seemed inversely related to the plasma TSH level. The extrathyroidal mast cells were never affected by changes in TSH. The findings indicate that, in mice, TSH induces the appearance of 5-HT-and histamine-containin...

Hypophyseal Changes Induced by Thyroid Deficiency and Thyroxine Administration as Revealed by Immunochemical Staining1

Abstract: The influence of thyroid deficiency and thyroxine administration on pituitary cell types was studied in the rat with the peroxidaselabeled antibody technique. Observations were made on TSH, growth hormone, prolactin, corticotropic and presumptive LH cells with special emphasis being placed on the nature of the thyroidectomy cell. The observations were compatible with the hypothesis that the thyroidectomy cell arises from the TSH cell, although derivation from other cell types was not ruled out. Thyroidectomy and castration cells appeared to be distinctive cell entities. As a result of thyroparathyroidectomy plus 131I-irradiation or treatment with propylthiouracil: most TSH cells lost their stainability except for the Golgi area and a few cytoplasmic granules; growth hormone cells could no longer be detected; prolactin and presumptive LH cells were reduced in size; and corticotropic cells seemed unaffected. TSH cells could no longer be identified following administration of thyroxine while growth hormone, ...

Neonatal Hyperthyroidism in an Infant Born of an Euthyroid Mother

Abstract: An infant with neonatal hyperthyroidism was born to an euthyroid mother previously treated for hyperthyroidism with sodium iodide I 131. Measurable levels of long-acting thyroid stimulator (LATS) were found in mother and infant. A review of previous cases of neonatal hyperthyroidism in which LATS determinations have been performed indicates the importance of LATS in the pathogenesis of this condition. Infants born of mothers with hyperthyroidism or with a history of treated hyperthyroidism should be evaluated in the neonatal period for hyperthyroidism, particularly if measurable levels of LATS have been found in the mother's serum late in pregnancy. Early treatment of neonatal thyrotoxicosis with propylthiouracil is recommended for severely affected cases.

Disseminated Intravascular Coagulation Complicating Propylthiouracil Therapy A Case Description of a 16-Year-Old Girl

Abstract: A 16-year-old girl with thyrotoxicosis, treated successfully for two years with propylthiouracil, developed a purpuric rash, prolonged pro- thrombin time, increased split fibrin products, elevated antinuclear anti body titer and glomerular changes The symptoms abated after ther apy with heparin and prednisone, although the ANA titer remained elevated This is presented as the first reported instance of dissem inated intravascular clotting resulting from propylthiouracil therapy

The identification of the thyrotropic cells in the adenohypophysis of the cichlid fish Cichlasoma biocellatum and the role of these cells and of the thyroid in osmoregulation

Abstract: In order to identify the thyrotropic cells in the pituitary gland of Cichlasoma biocellatum, adult animals were treated with thyroxine. Periodic acid Schiff (PAS)- and aldehyde fuchsin (AF)-positive, and Alcian blue (AB)-negative basophils in the meso-adenohypophysis as well as the thyroid were strongly inactivated by such treatment. Since other cell types in the adenohypophysis were not affected, it is concluded that the PAS-positive and AB-negative basophils in the meso-adenohypophysis are the thyrotrops. In normal animals the thyrotrops and the thyroid are very active. Propylthiouracil did not cause a further activation of TSH cells. Keeping the animals in 25% sea-water caused a strong inactivation of the prolactin cells, the thyrotrops and the thyroid. In deionized water the prolactin cells were stimulated, but the thyroid was less active than in controls. Injections of ovine prolactin did not enhance the activity of the thyroid in salt water animals. It is suggested that in Cichlasoma biocellatum prolactin does not have a direct stimulatory effect on the thyroid.

Simultaneous Effects of Thyroid and Adrenal Inhibitors on Maternal-Fetal Endocrine Interrelations in the Rat

Abstract: Functional alterations in the pituitary-thyroid and adrenocortical systems of mother and newborn were studied after treatment of pregnant rats (last 7–10 days of gestation) with chemical agents known to influence thyroid and adrenal gland function. Amphenone treatment (25–30 rag, sc, twice daily, 10 days) resulted in adrenal and thyroid gland hypertrophy and augmentation of 131I uptake by the latter. With shorter treatment, radioiodine uptakes by the enlarged thyroids were decreased and corticosteroid levels in plasma and adrenal were depressed. Effects on the fetal pituitarythyroid system were marked. Newborn from Amphenone-treated mothers showed enlarged thyroids (3-fold) with sharply decreased 131I uptake. Fetal goitrogenesis was associated with pituitary enlargement but adrenal hypertrophy in newborn was only of moderate degree and was not accompanied by significant change in adrenocorticosteroid content. Plasma and pituitary TSH levels in goitrous newborn were increased 200–300%. Conjoint administrat...

Changes of the radioactive iodine uptake and in the iodoamino acids pattern of thyroid in rats in the course of advancement of iodine deficiency.

Abstract: Hourly changes of 131I uptake and the changes in several indices of thyroid at different time intervals after beginning of an iodine deficient diet with or without propylthiouracil were determined. An amino acid mixture was used as the protein source in the present experiments. The magnitude of iodine uptake and the ratio of monoiodotyrosine to diiodotyrosine increased according to the length of time on low iodine diet. The earlier appearance and more enlargement of peak of the ratio of monoiodotyrosine to diiodotyrosine in rats treated with small dose of propylthiouracil than in those untreated suggested that propylthiouracil might also bring about the lack of iodine by inhibiting the iodination at substrate level.

Paradoxical stimulation of thyroid function by cortisone in the rat.

Abstract: We have studied the effect of cortisone on 131I metabolism of highly stimulated rat thyroids. Rats were fed a low-iodine diet (LID) containing 0.15% propylthiouracil (PTU) for 7 days. The PTU diet was withdrawn on day S and LID alone fed for another 4 days. Half of the animals received 5 mg cortisone daily from day 6 to the day of autopsy. The 4-hr thyroid 131I uptake was consistently higher in the cortisone-treated rats than in the controls after PTU withdrawal. Similar differences between cortisone and control groups were seen in acutely nephrectomized rats and in those hypophysectomized and maintained with TSH. Higher T3*/T4* and MIT*/DIT* ratios were found in the digested thyroids of the intact cortisonetreated rats than in the controls. The T/S (TcO4–) was significantly higher in cortisonetreated animals than in controls. A single injection of cortisone did not affect the 4-hr thyroid 131I uptake in PTU-withdrawal rats, but decreased the 12 and 24-hr 131I accumulation. The increase in thyroid 131I me...