Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
2005-8-31
pubmed:abstractText
Iodothyronine deiodinases (D1, D2, and D3) comprise a family of selenoproteins that are involved in the conversion of thyroxine (T(4)) to active triiodothyronine (T(3)), and also the inactivation of both thyroid hormones. The deiodinase enzymes are of critical importance for the normal development and function of the central nervous system. D1 is absent from the human brain, suggesting that D2 and D3 are the two main enzymes involved in the maintenance of thyroid hormone homeostasis in the central nervous system, D2 as the primary T(3)-producing enzyme, and D3 as the primary inactivating enzyme. While the coordinated action of D2 and D3 maintain constant T(3) levels in the cortex independently from the circulating thyroid hormone levels, the role of deiodinases in the hypothalamus may be more complex, as suggested by the regulation of D2 activity in the hypothalamus by infection, fasting and changes in photoperiod. Tanycytes, the primary source of D2 activity in the hypothalamus, integrate hormonal and probably neuronal signals, and under specific conditions, may influence neuroendocrine functions by altering local T(3) tissue concentrations. This function may be of particular importance in the regulation of the hypothalamic-pituitary-thyroid axis during fasting and infection, and in the regulation of appetite and reproductive function. Transient expression of D3 in the preoptic region during a critical time of development suggests a special role for this deiodinase in sexual differentiation of the brain.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
1050-7256
pubmed:author
pubmed:issnType
Print
pubmed:volume
15
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
883-97
pubmed:meshHeading
pubmed-meshheading:16131331-Animals, pubmed-meshheading:16131331-Appetite, pubmed-meshheading:16131331-Brain, pubmed-meshheading:16131331-Cachexia, pubmed-meshheading:16131331-Fasting, pubmed-meshheading:16131331-Gene Expression Regulation, Developmental, pubmed-meshheading:16131331-Humans, pubmed-meshheading:16131331-Hypothalamus, pubmed-meshheading:16131331-Hypothyroidism, pubmed-meshheading:16131331-Infection, pubmed-meshheading:16131331-Iodide Peroxidase, pubmed-meshheading:16131331-Light, pubmed-meshheading:16131331-Models, Biological, pubmed-meshheading:16131331-Neurons, pubmed-meshheading:16131331-Neurosecretory Systems, pubmed-meshheading:16131331-RNA, Messenger, pubmed-meshheading:16131331-Rats, pubmed-meshheading:16131331-Sex Differentiation, pubmed-meshheading:16131331-Thyroid Diseases, pubmed-meshheading:16131331-Thyroid Hormones, pubmed-meshheading:16131331-Tissue Distribution, pubmed-meshheading:16131331-Triiodothyronine
pubmed:year
2005
pubmed:articleTitle
Role of thyroid hormone deiodination in the hypothalamus.
pubmed:affiliation
Tupper Research Institute and Department of Medicine, Tufts-New England Medical Center, and Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111, USA. rlechan@tufts-nemc.org
pubmed:publicationType
Journal Article, Review