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24.10.2002 | 11:23 AM
Agouti-Related Protein (AGRP) Has a Central Inhibitory Action on the Hypothalamic-Pituitary-Thyroid (HPT) Axis; Comparisons between the Effect of AGRP and Neuropeptide Y on Energy Homeostasis and the HPT Axis.
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Because – MSH has a potent stimulatory action on hypo- physiotropic TRH synthesizing neurons in the hypothalamic paraventricular nucleus (PVN), preventing the effects of fast- ing on the gene expression of the TRH prohormone (proTRH), we hypothesized that agouti-related protein (AGRP), a mela- nocortin receptor antagonist, may exert a central inhibitory action on these neurons. […]

24.09.2002 | 11:31 AM
Ubc6p and Ubc7p Are Required for Normal and Substrate-Induced Endoplasmic Reticulum- Associated Degradation of the Human Selenoprotein Type 2 Iodothyronine Monodeiodinase.
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The type 2 monodeiodinase (D2) is an endoplasmic reticulum-resident membrane selenoprotein re- sponsible for catalyzing the first step in thyroid hormone action, T4 deiodination to T3. Its short half-life is due to ubiquitination and proteolysis by proteasomes, a mechanism that is accelerated by D2 interaction with T4. To identify proteins involved in D2 ubiquitination, a […]

02.08.2002 | 11:36 AM
AR Signaling Required for Diet-Induced Thermogenesis and Obesity Resistance.
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Excessive caloric intake is thought to be sensed by the brain, which then activates thermogenesis as a means of preventing obesity. The sympathetic nervoussystem, through – adrenergicreceptor( AR)actionontargettissues, is likely the efferent arm of this homeostatic mechanism. To test this hypoth- esis, we created mice that lack the three known ARs ( -less mice). -less […]

29.07.2002 | 11:00 AM
Impact of Gene Cloning, Disruption and Over-Expression of Iodothyronine Deiodinases on Thyroid Hormone Homeostasis.
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Thyroxine (T4) is the main product of thyroid secretion, a pro-hormone that must be activated by deiodination to T3 in order to initiate thyroid hormone action. This deiodination reaction occurs in the phenolic-ring (outer-ring deiodination, ORD) of the T4 molecule and is catalyzed by two selenocysteine-containing deiodinases, i.e. D1 and D2. As a counter point […]

24.06.2002 | 11:42 AM
Severe and Mild Neonatal Hypothyroidism Mediate Opposite Effects on Leydig Cells of Rats.
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The effects of neonatal hypothyroidism on the number of Leydig cells were studied in neonatal Wistar rats. Moderate or severe hypothyroidism were induced during neonatal life by giving different amounts of methi- mazole (MMI; 0.05% or 0.1%) in the drinking water of pregnant and lactating dams. Rats were sacrificed on day 21 of postnatal life. […]

30.11.2001 | 9:12 AM
The type 2 iodothyronine deiodinase is essential for adaptive thermogenesis in brown adipose tissue.
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Type 2 iodothyronine deiodinase (D2) is a selenoenzyme, the product of the recently cloned cAMP- dependent Dio2 gene, which increases 10- to 50-fold during cold stress only in brown adipose tissue (BAT). Here we report that despite a normal plasma 3,5,3′-triiodothyronine (T3) concentration, cold- exposed mice with targeted disruption of the Dio2 gene (Dio2–/–) become […]

10.08.2001 | 9:20 AM
The Human Type 2 Iodothyronine Deiodinase Is a Selenoprotein Highly Expressed in a Mesothelioma Cell Line.
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Types 1 and 3 iodothyronine deiodinases are known to be selenocysteine-containing enzymes. Although a putative human type 2 iodothyronine deiodinase (D2) gene (hDio2) encoding a similar selenoprotein has been identified, basal D2 activity is not selenium (Se)-dependent nor has D2 been labeled with 75Se. A human mesothelioma cell line (MSTO- 211H) has recently been shown […]

30.07.2001 | 9:39 AM
Thyroid hormone–sympathetic interaction and adaptive thermogenesis are thyroid hormone receptor isoform–specific.
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In newborns and small mammals, cold-induced adaptive (or nonshivering) thermogenesis is pro- duced primarily in brown adipose tissue (BAT). Heat production is stimulated by the sympathetic nervous system, but it has an absolute requirement for thyroid hormone. We used the thyroid hor- mone receptor-β–selective (TR-β–selective) ligand, GC-1, to determine by a pharmacological approach whether adaptive […]

30.07.2001 | 9:32 AM
Thyroid hormone stimulation of osteocalcin gene expression in ROS 17/2·8 cells is mediated by transcriptional and post-transcriptional mechanisms.
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We investigated the mechanism of thyroid hormone regulation of osteocalcin (OC) gene expression in osteoblast-like cells (ROS 17/2·8). Treatment with tri- iodothyronine (T3) (10 8 M) increased OC mRNA levels by 3-fold after 24 h and reached a maximum, 5·4-fold, after 48 h. The mRNA levels of other bone- specific genes, alkaline phosphatase and osteopontin, […]