Publications by authors named "Gondou A"

We previously demonstrated that iodothyronine 5'-deiodination (5'D) activity is present and increased by triiodothyronine (T3) and angiotensin II (Ang II) in cultured rat cardiac myocytes. To further elucidate the stimulatory mechanism of Ang II, we investigated the effect of intracellular Ca2+ and protein kinase C on myocardial 5'D activity. Moreover, to elucidate the molecular mechanism of the stimulatory effect of T3 and Ang II, we detected the mRNA levels by means of a reverse-transcriptase polymerase chain reaction (RT-PCR).

View Article and Find Full Text PDF

We investigated the effects of streptozotocin (STZ)-induced diabetes on thyroid hormone levels, type 1 deiodinase (D1) activity and messenger RNA (mRNA) levels in inherited D1 deficient C3H mice in a comparative manner with control C57 mice. The apparent maximum velocity (Vmax) D1 values in C3H mice were 3% (liver) and 26% (kidney) of those in C57 mice. In C3H mice, similar serum T3, slightly higher T4, and 2.

View Article and Find Full Text PDF
Article Synopsis
  • The research explores how triiodothyronine (T3) is produced from thyroxine (T4) in the brain and the role of the enzyme type 2 deiodinase (D2) in this process.
  • The study focuses on the effects of nicotine and the blocker mecamylamine on D2 activity in rat mixed glial cells, highlighting the importance of glial cells in thyroid hormone regulation.
  • Results show that nicotine significantly boosts D2 activity in a dose-dependent manner, suggesting that nicotine influences brain function through nicotinic acetylcholine receptors by affecting thyroid hormone metabolism.
View Article and Find Full Text PDF

To evaluate the age- and sex-related changes in Type 1 iodothyronine deiodinase gene expression in the liver and kidneys, we measured 5'-deiodinating activity and deiodinase mRNA in developing rats. The activity in the liver increased after birth, and that in neonates was approximately half that in adults. In contrast, the activity in neonatal kidneys remained very low.

View Article and Find Full Text PDF

To evaluate the regulatory mechanism of human Type 1 iodothyronine deiodinase (D1) gene expression, we measured the D1 mRNA levels in peripheral blood mononuclear cells (PBMC) in normal control subjects and in patients with Graves' disease. We used competitive reverse transcriptase-polymerase chain reaction with the deleted complimentary RNA of D1 as the standard for quantification. The D1 mRNA levels in PBMC were increased significantly in patients with Graves' disease compared with that in normal controls.

View Article and Find Full Text PDF

We investigated the effects of cyclic guanosine 3',5'-monophosphate (cGMP) on type 2 iodothyronine deiodinase (D2) in cultured rat glial cells. Rat glial cells were cultured in Dulbecco's modified Eagle's medium supplemented with 15% fetal bovine serum. When cells were cultured in the presence of 8-bromo cGMP (8-Br cGMP), an analogue of cGMP, D2 activity was increased in a time- and concentration-dependent manner.

View Article and Find Full Text PDF

A nine-year old boy developed reduced growth velocity at the age of seven. The peak plasma growth hormone (GH) response to 3,4-dihydroxyphenylalanine, GH-releasing factor and insulin was 10.2, 8.

View Article and Find Full Text PDF

To evaluate the relationship between eye changes and autoantibody to the thyrotropin receptor in patients with Graves' disease, we evaluated the eye changes using magnetic resonance imaging and the results were correlated with thyroid-stimulating antibody, thyrotropin binding inhibitor immunoglobulin and thyroid growth activity. Subjects were 15 patients with Graves' disease who had Graves' ophthalmopathy, including exophthalmos and other signs and symptoms, and nine patients without ophthalmopathy; all were maintained in a euthyroid state by antithyroid drugs. The thyrotropin-binding inhibitor immunoglobulin was measured by a kit, and thyroid-stimulating antibody and thyroid growth activity were evaluated by cyclic adenosine 3',5'-monophosphate production and [3H]thymidine incorporation, respectively, by cultured functional rat thyroid lined cells.

View Article and Find Full Text PDF

We investigated the regulation of type I iodothyronine 5'-deiodinase (5'-D) gene expression by TSH and T3 in FRTL-5 rat thyroid cells. Northern blot analysis revealed that these cells express a 5'-D messenger RNA (mRNA) species of 2.1 kilobases.

View Article and Find Full Text PDF

N-Bromoacetyl-[125I]T4(BrAc[125I]T4) was used as affinity label to identify type I 5'-deiodinase (5'-D) in human thyroid glands. Affinity labeled proteins were analyzed by autoradiography after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Human thyroid microsomes labeled with BrAc[125I]T4 showed the most prominent radiolabeled band of protein at a mol wt of approximately 27,000 (p27).

View Article and Find Full Text PDF