Linked Life Data

2306123

Source:http://linkedlifedata.com/resource/pubmed/id/2306123

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1990-3-20
pubmed:abstractText
The aging process is generally associated with marked decreases in the activities of numerous enzymes as well as lower levels of sex hormones such as testosterone. We therefore examined testosterone metabolism in liver microsomes from individual 3- and 24-month-old male rats. Although the old rats exhibited lower 16 alpha-, 6 beta-, and 2 alpha-hydroxylase activities than the young rats, the old rats had a higher 7 alpha-hydroxylase activity. Immunoquantitation of P450a, a known 7 alpha-hydroxylase, showed that the level of this protein was elevated in the old rats, and was correlated with 7 alpha-hydroxylase activity. The mRNA for P450a was measured with a cDNA probe and its level was fivefold higher in the old rats, whereas levels of mRNA coding for a 6 beta-hydroxylase P450 were markedly decreased. The increased expression of cytochrome P450a demonstrates that the observed common decrease in cytochrome P450-catalyzed activities with senescence is not a universal phenomenon. Thus, constitutive expression of specific cytochrome P450 genes is repressed or activated in senescent rats.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0003-9861
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
277
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
42-6
pubmed:dateRevised
2003-11-14
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Developmental regulation of hepatic testosterone hydroxylases: simultaneous activation and repression of constitutively expressed cytochromes P450 in senescent rats.
pubmed:affiliation
Laboratory of Molecular Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892.
pubmed:publicationType
Journal Article