Type 1 iodothyronine deiodinase in heart --effects of triiodothyronine and angiotensin II on its activity and mRNA in cultured rat myocytes.

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).

Effect of streptozotocin-induced diabetes mellitus on type 1 deiodinase (D1) in inherited D1-deficient mice.

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.

Effect of nicotine on type 2 deiodinase activity in cultured rat glial cells.

Intracellular generation of triiodothyronine (T3) from thyroxine (T4) by type 2 deiodinase (D2) in the mammalian brain, plays a key role in thyroid hormone action. The presence of D2 in rat astrocytes suggests the importance of glial cells in the regulation of intracellular T3 levels in the rat central nervous system (CNS). To analyze further the factors that regulate D2 activity in the CNS, we investigated the effects of nicotine and of mecamylamine, which inhibits the binding of nicotine with nicotinic acetylcholine receptors, on D2 activity in cultured mixed glial cells of the rat brain.

Age- and sex-related changes in type-1 iodothyronine deiodinase messenger ribonucleic acid in rat liver and kidney.

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.

Quantitative measurements for type 1 deiodinase messenger ribonucleic acid in human peripheral blood mononuclear cells: mechanism of the preferential increase of T3 in hyperthyroid Graves' disease.

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.