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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1990-6-1
pubmed:abstractText
We previously found an age-dependent impairment of induction of lipogenic enzymes in rat liver [Iritani et al. (1981) Biochim. Biophys. Acta 665, 636-639]. Further, we have found that after refeeding a fat-free diet to fasted rats, increases in transcriptional rate, mRNA concentration and enzyme induction of hepatic malic enzyme and glucose-6-phosphate dehydrogenase were always lower in 18-month-old rats than in 1.5-month-old rats. In the young rats, the transcriptional rates reached the maximum level in 4 h and the mRNA reached maximum levels in 16 h. The peaks tended to delay in the older rats. The half-lives of the mRNAs were not significantly longer in the old than in the young animals. The incorporation of [3H]leucine into the enzyme proteins was also decreased roughly in proportion to the enzyme induction. The mRNA concentrations in the liver polysomes were roughly proportional to the total mRNA. Thus, no effects of ageing on mRNA stability or on the translational activity of the enzymes could be found. It is suggested that the age-dependent decreases of malic enzyme and glucose-6-phosphate dehydrogenase induction can be mainly ascribed to the transcriptional steps. Moreover, the transcriptional rate, mRNA concentration and induction of malic enzyme were increased by triiodothyronine treatment at a similar rate in both the young and old rats, but the absolute increments were lower in the old animals. The triiodothyronine response to malic enzyme induction also appeared to be primarily decreased at the transcription level.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0014-2956
pubmed:author
pubmed:issnType
Print
pubmed:day
30
pubmed:volume
188
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
517-22
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Effects of ageing on transcriptional and post-transcriptional regulation of malic enzyme and glucose-6-phosphate dehydrogenase in rat liver.
pubmed:affiliation
Tezukayama Gakuin College, Osaka, Japan.
pubmed:publicationType
Journal Article