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17.07.2008 | 10:47 AM

Deiodinase-mediated thyroid hormone inactivation minimizes thyroid hormone signaling in the early development of fetal skeleton.

Thyroid hormone (TH) plays a key role on post-natal bone development and metabolism, while its relevance during fetal bone development is uncertain. To study this, pregnant mice were made hypothyroid and fetuses harvested at embryonic days (E) 12.5, 14.5, 16.5 and 18.5. Despite a marked reduction in fetal tissue concentration of both T4 and T3, […]

17.06.2008 | 11:01 AM

The Thyroid Hormone Inactivating Deiodinase Functions as Homodimer.

To explore the effect of refeeding on recovery of TRH gene expression in the hypothalamic paraventricular nucleus (PVN) and its correlation with the feeding-related neuropep- tides in the arcuate nucleus (ARC), c-fos immunoreactivity (IR) in the PVN and ARC 2 h after refeeding and hypothalamic TRH, neuropeptide Y (NPY) and agouti-related protein (AGRP) mRNA levels […]

08.05.2008 | 11:32 AM

Expression Patterns of WSB-1 and USP-33 Underlie Cell-Specific Posttranslational Control of Type 2 Deiodinase in the Rat Brain.

The type 2 deiodinase (D2) activates thyroid hormone and constitutes an important source of 3,5,3 ,-triiodothyronine in the brain. D2 is inactivated via WSB-1 mediated ubiquitina- tion but can be rescued from proteasomal degradation by USP-33 mediated deubiquitination. Using an in silico analysis of published array data, we found a significant positive cor- relation between […]

08.05.2008 | 11:25 AM

Thyroid Function Disturbance and Type 3 Iodothyronine Deiodinase Induction after Myocardial Infarction in Rats—A Time Course Study.

In humans, there is a significant decrease in serum T3 and increase in rT3 at different time points after myocardial in- farction, whereas serum TSH and T4 remain unaltered. We report here a time course study of pituitary-thyroid function and thyroid hormone metabolism in rats subjected to myo- cardial infarction by left coronary ligation (INF). […]

08.05.2008 | 11:11 AM

Feeding and Metabolism in Mice Lacking Pituitary Adenylate Cyclase-Activating Polypeptide.

Disruption of the pituitary adenylate cyclase-activating polypeptide (PACAP) gene in mice has demonstrated a role for this highly conserved neuropeptide in the regulation of me- tabolism and temperature control. Localization of PACAP neurons within hypothalamic nuclei that regulate appetite suggest PACAP may affect feeding and thus energy balance. We used PACAP-null mice to address this […]

17.03.2008 | 11:17 AM

Hypoxia-inducible factor induces local thyroid hormone inactivation during hypoxic-ischemic disease in rats.

Thyroid hormone is a critical determinant of cellular metabolism and differentiation. Precise tissue-specific regulation of the active ligand 3,5,3′-triiodothyronine (T3) is achieved by the sequential removal of iodine groups from the thyroid hormone molecule, with type 3 deiodinase (D3) comprising the major inactivating pathway that terminates the action of T3 and prevents activation of the […]

04.09.2007 | 11:33 AM

Sonic hedgehog-induced type 3 deiodinase blocks thyroid hormone action enhancing proliferation of normal and malignant keratinocytes.

The Sonic hedgehog (Shh) pathway plays a critical role in hair follicle physiology and is constitutively active in basal cell carcino- mas (BCCs), the most common human malignancy. Type 3 iodo- thyronine deiodinase (D3), the thyroid hormone-inactivating en- zyme, is frequently expressed in proliferating and neoplastic cells, but its role in this context is unknown. […]

27.06.2007 | 10:54 AM

Effects of Rexinoids on Thyrotrope Function and the Hypothalamic-Pituitary-Thyroid Axis.

Retinoid X receptor (RXR)-selective retinoids (rexinoids) can cause central hypothyroidism in humans, and this effect has been confirmed in rodent models. In this report, we charac- terized the effect of rexinoids on the hypothalamic-pituitary- thyroid axis in mice and TSH regulation in a thyrotrope-de- rived cell line. The synthetic rexinoid (LG 268) suppressed TSH and […]

27.06.2007 | 10:21 AM

Atypical Expression of Type 2 Iodothyronine Deiodinase in Thyrotrophs Explains the Thyroxine-Mediated Pituitary Thyrotropin Feedback Mechanism.

Type 2 iodothyronine deiodinase (D2) activates T4 by deiodi- nation to T3, a process being the source of most T3 present in the brain. In the mediobasal hypothalamus, expression of the dio2 gene is potently activated by administration of bacterial lipopolysaccharide (LPS), which in turn mediates the modi- fications in thyroid homeostasis typically observed in […]

17.06.2007 | 11:45 AM

Type 2 iodothyronine deiodinase is highly expressed in germ cells of adult rat testis.

The testis has been classically described as a thyroid hormone unresponsive tissue, but recent studies indicate that these hormones might play an important role in developing testes. We have previously demonstrated that type 2 iodothyronine deiodinase (D2), a thyroid hormone-activating enzyme, is expressed in adult rodent testis and that its activity is induced by hypothyroidism. […]