Linked Life Data

8429259

Source:http://linkedlifedata.com/resource/pubmed/id/8429259

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1993-3-5
pubmed:abstractText
The genes coding for apolipoproteins A-I, C-III, and A-IV are closely linked to one another in the rat genome. Thyroid hormone stimulates apoA-I expression in rat liver by an unusual mechanism that enhances the maturation of mRNA. This hormone also increases apoA-IV mRNA abundance by a mechanism not yet studied, and its role in the expression of apoC-III has not been defined but may be of relevance to the metabolism of triglyceride-rich lipoproteins. We therefore measured the transcriptional activity of the apoA-IV and apoC-III genes and the abundance of their nuclear RNA and total cellular mRNA in livers of control rats and rats made hyper- and hypothyroid. After a single receptor-saturating dose of triiodothyronine (3 mg/100 g body weight), apoA-IV gene transcription increased at 20 min and reached a maximum of 260% of control at 6 h. Increases of transcription were reflected in increases of nuclear and total apoA-IV mRNA levels. ApoC-III gene transcription was temporarily increased to 160% at 2 h without changes in the abundance of its nuclear or total mRNA over 24 h. Lower hormone doses (20-500 micrograms/100 g body weight) stimulated apoA-IV mRNA transcription as well, but tended to reduce transcription from the apoC-III gene. Upon chronic administration of thyroid hormone, apoA-IV transcription decreased to 55% and nuclear apoA-IV RNA levels to 87% of control. However, total cellular apoA-IV mRNA levels increased to 279% of control, implying stabilization of mRNA in the cytoplasm. ApoC-III transcription decreased to 28% of control, but abundance of nuclear and total cellular apoC-III mRNA was reduced to a lesser extent. In hypothyroid rats, apoA-IV gene expression was decreased fourfold at the transcriptional level. In contrast, apoC-III gene transcription increased to 178% of control, but the abundance of nuclear and total cellular apoC-III mRNA did not differ from control rats. Thus, thyroid hormone affects the abundance of apoA-IV mRNA by changing its synthesis and its rate of degradation and enhances the efficiency of apoC-III mRNA maturation, thereby blunting the net effect of altered mRNA synthesis on mRNA abundance.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0022-2275
pubmed:author
pubmed:issnType
Print
pubmed:volume
34
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
249-59
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:8429259-Animals, pubmed-meshheading:8429259-Apolipoprotein C-III, pubmed-meshheading:8429259-Apolipoproteins A, pubmed-meshheading:8429259-Apolipoproteins C, pubmed-meshheading:8429259-Base Sequence, pubmed-meshheading:8429259-Blotting, Northern, pubmed-meshheading:8429259-Gene Expression, pubmed-meshheading:8429259-Hyperthyroidism, pubmed-meshheading:8429259-Hypothyroidism, pubmed-meshheading:8429259-Kinetics, pubmed-meshheading:8429259-Liver, pubmed-meshheading:8429259-Male, pubmed-meshheading:8429259-Molecular Sequence Data, pubmed-meshheading:8429259-Propylthiouracil, pubmed-meshheading:8429259-RNA, Messenger, pubmed-meshheading:8429259-Rats, pubmed-meshheading:8429259-Rats, Sprague-Dawley, pubmed-meshheading:8429259-Transcription, Genetic, pubmed-meshheading:8429259-Triiodothyronine
pubmed:year
1993
pubmed:articleTitle
Role of thyroid hormone in the expression of apolipoprotein A-IV and C-III genes in rat liver.
pubmed:affiliation
Department of Medicine, Baylor College of Medicine, Houston, TX 77030.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't