Linked Life Data

8143897

Source:http://linkedlifedata.com/resource/pubmed/id/8143897

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1-2
pubmed:dateCreated
1994-5-5
pubmed:abstractText
Thyroid hormone (TH) metabolism is altered in cases of unconjugated hyperbilirubinemia. These effects might involve inhibition of TH uptake by their target cells. Astrocytes, which are in close contact with the membranes of brain capillaries, might be the first brain cells to come into contact with bilirubin. Cultured rat brain astrocytes were used as a model to study the effects of bilirubin and bilirubin analogues on TH uptake. The initial uptake of [125I]T3 and [125I]T4 was inhibited by unconjugated bilirubin, biliverdin, ditaurobilirubin and bilirubin glucuronides. The inhibition of T3 uptake by the bilirubin analogues was competitive. The Ki values were: unconjugated bilirubin (31 microM), biliverdin (48 microM), ditaurobilirubin (2.5 microM) and bilirubin glucuronides (1.2 microM). This last value is similar to the Km of T3 transport (0.4 microM), indicating that bilirubin glucuronides have a high affinity for the TH transport system. By contrast, the uptakes of [3H]tryptophan and ]3H]glutamine were not inhibited. These results suggest that the astrocyte plasma membrane bears specific bilirubin-interaction sites that are closely related to the TH transport system. However, uptake of [14C]bilirubin by cultured astrocytes was a non-saturable process. Binding of bilirubin to the astrocyte plasma membrane may inhibit the TH uptake and impair their metabolism and their action on the intracellular targets.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0303-7207
pubmed:author
pubmed:issnType
Print
pubmed:volume
97
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
145-51
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
Competitive inhibition of thyroid hormone uptake into cultured rat brain astrocytes by bilirubin and bilirubin conjugates.
pubmed:affiliation
Unité de Recherche sur la Glande Thyroïde et la Regulation Hormonale (Unité 96), Institut National de la Santé et de la Recherche Médicale, Le Kremlin-Bicêtre, France.
pubmed:publicationType
Journal Article, Comparative Study