Propylthiouracil

About: Propylthiouracil is a research topic. Over the lifetime, 2181 publications have been published within this topic receiving 46996 citations. The topic is also known as: Thyreostat® & 2,3-dihydro-6-propyl-2-thioxo-4(1H)-pyrimidinone.

Renin-angiotensin system in hypothyroid rats: effects of potassium iodide and triiodo-L-thyronine.

Abstract: Kinetic studies of the renin-angiotensin system (RAS) were carried out by measuring plasma renin activity (PRA), plasma renin concentration (PRC) and plasma renin substrate (PRS). Changes in this system were studied during hypothyroidism, after administration of propylthiouracil (PTU), and in thyroidectomized rats. A significant decrease in PRA and PRC was observed in those animals previously treated with PTU. However, a significant increase in PRC, and a decrease in PRS, were found in T animals, but no changes in PRA were observed. In these animals, after daily administration of potassium iodide for 1 week (T + KI), no changes in RAS were observed in comparison with T rats. Nevertheless, administration of daily doses of triiodo-L-thyronine (T + T3) induced a significant increase in PRA, leaving PRC unaltered. In this case the changes in PRA were related to the increase in PRS after T3 treatment. These results suggest that two different mechanisms were involved in renin release, one activated in T rats and the other in pharmacological hypothyroidism.

Thyroid storm in an 11-year-old boy managed by propranolol.

Abstract: An 11-year-old boy with an 18-month history of incompletely treated thyrotoxicosis was hospitalized because of progressive weakness. During his first hospital day he suddenly decompensated, with signs of acute thyroid storm. He responded dramatically to intravenously and then orally administered propranolol which controlled his hyperthyroid symptomatology until propylthiouracil could take effect. This is the first reported description of the use of propranolol in the treatment of thyroid storm in childhood thyrotoxicosis.

Changes in hepatic insulin-like growth factor-binding proteins -1, -2 and -3 mRNA levels in rats with altered thyroid status

Abstract: Changes in thyroid status have a major effect on the GH/insulin-like growth factor (IGF) axis. The majority of IGF in the circulation is bound to specific IGF-binding proteins (IGFBPs) of which six have been cloned and sequenced. We have studied changes in hepatic gene expression of IGFBP-1, -2 and -3, in male Wistar rats rendered hyperthyroid (thyroxine, 200 micrograms/kg per day) or hypothyroid (propylthiouracil, 0.1% daily). Littermates of the same age were used as controls (n = 6 in each group). Thyroxine was measured by radioimmunoassay, and hepatic IGFBP-1, -2 and -3 mRNA levels by Northern blot analysis using specific rat cDNA probes with a 28S ribosomal probe as a loading control. Mean +/- S.E.M. thyroxine levels were 247.0 +/- 44.5 (hyperthyroid group), < 9.0 (hypothyroid group) and 76.0 +/- 4.5 nmol/l (control group). IGFBP-1 and -2 mRNA levels in the hypothyroid animals compared with the controls were significantly increased, but similar levels of expression were found in thyrotoxic and control rats. IGFBP-3 mRNA levels in hypothyroid animals were decreased, and increased in thyrotoxic animals. Thus, in the adult rat, hypothyroidism is associated with increased hepatic IGFBP-1 and -2 gene expression, but decreased IGFBP-3 gene expression, while in thyrotoxicosis there are normal IGFBP-1 and -2 mRNA levels but increased IGFBP-3 gene expression. These results suggest that there is specific and different transcriptional regulation for IGFBP-1, -2 and -3 in hypo- and hyperthyroid rats.

Mechanism of thioamide antithyroid drug associated hypoprothrombinemia.

Abstract: The thioamide class of antithyroid drugs has been associated with the development of hypoprothrombinemia. Two drugs in this class, propylthiouracil and methimazole, resemble the methyltetrazole-thiol leaving group of certain cephalosporin antibiotics. Both were found in vitro to inhibit the vitamin K dependent step in clotting factor synthesis, the gamma-carboxylation of glutamic acid with 50 per cent inhibitory concentrations of 2 mM for propylthiouracil and 0.1 mM for methimazole. Methimazole was also found to inhibit vitamin K epoxide reductase, an enzyme related to the carboxylation reaction, with a 50 per cent inhibitory concentration of 25 uM. In vivo methimazole, administered twice at a dose of 500 mg/kg to rats on a vitamin K deficient diet produced hypoprothrombinemia. These results suggest that the mechanism of hypoprothrombinemia associated with thioamide antithyroid drugs may be similar to the mechanism of hypoprothrombinemia associated with cephalosporins which contain the methyltetrazole-thiol leaving group.

Evaluation of goitrogenic and antithyroidal effect of the fern Adiantum capillus-veneris

Abstract: Adiantum capillus-veneris L., Pteridaceae, is a fern reputed to have numerous applications in traditional medicine in the treatment of leprosy, animal bites, thyroid dysfunction and musculoskeletal disorder. The proposed study was aimed to investigate the potency of the fern Adiantum capillus-veneris on the thyroid dysfunction - hypothyroidism in terms of determining thyroid gland weight, thyroid peroxidase activity, estimation of iodine in urine, concentrations of total thyroxine (T4), triiodothyronine (T3) and thyroid stimulating hormone (TSH) in serum. The weight of thyroid gland was decreased, while thyroid peroxidase activity, serum T4 (p < 0.01) and serum T3 levels (p < 0.01) were increased in animals treated with the ethanol plant extract (500 mg/kg); but serum TSH level decreased significantly (p < 0.01) when compared with hypothyroid control animals. The SOD, Catalase and glutathione antioxidant enzyme levels and lipid peroxidation were measured. The results of lipid peroxidation and antioxidant enzyme assay indicated that the level of malondialdehyde was significantly lowered and the levels of antioxidant enzymes were significantly increased when treated with ethanol extract of Adiantum capillus (500 mg/kg). Polyphenolic compounds viz., quercetin and gallic acid were determined by HPTLC analysis. With the outlined results, Adiantum capillus could be used for the regulation of hypothyroidism.