Linked Life Data

15026084

Source:http://linkedlifedata.com/resource/pubmed/id/15026084

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2004-3-17
pubmed:abstractText
In aged rats, trophic hormone-stimulated testosterone secretion by isolated Leydig cells is greatly reduced. The current studies were initiated to establish a functional link between excess oxidative stress and the age-related decline in steroidogenesis. Highly purified Leydig cell preparations obtained from 5-month (young mature) and 24-month (old) Sprague-Dawley rats were employed to measure and compare levels of lipid peroxidation, non-enzymatic (alpha-tocopherol, ascorbic acid, and reduced/oxidized glutathione) and enzymatic (Cu, Zn-superoxide dismutase, Cu, Zn-SOD; Mn-superoxide dismutase, Mn-SOD; glutathione peroxidase-1, GPX-1, and catalase, CAT) anti-oxidants. The extent of lipid peroxidation (oxidative damage) in isolated membrane fractions was quantified by measuring the content of thiobarbituric acid-reactive substances (TBARS) under basal conditions, or in the presence of non-enzymatic or enzymatic pro-oxidants. Membrane preparations isolated from Leydig cells from old rats exhibited two- to three-fold enhancement of basal TBARS formation. However, aging had no significant effect on TBARS formation in response to either non-enzymatic or enzymatic pro-oxidants. Among the non-enzymatic anti-oxidants, the levels of reduced glutathione were drastically reduced during aging, while levels of alpha-tocopherol and ascorbic acid remained unchanged. Both steady-state mRNA levels and catalytic activities of Cu, Zn-SOD, Mn-SOD, and GPX-1 were also significantly lower in Leydig cells from 24-month-old rats as compared with 5-month-old control rats. In contrast, neither mRNA levels nor enzyme activity of catalase was sensitive to aging. From these data we conclude that aging is accompanied by reduced expression of key enzymatic and non-enzymatic anti-oxidants in Leydig cells leading to excessive oxidative stress and enhanced oxidative damage (lipid peroxidation). It is postulated that such excessive oxidative insult may contribute to the observed age-related decline in testosterone secretion by testicular Leydig cells.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0960-0760
pubmed:author
pubmed:issnType
Print
pubmed:volume
88
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
61-7
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:15026084-Aging, pubmed-meshheading:15026084-Animals, pubmed-meshheading:15026084-Antioxidants, pubmed-meshheading:15026084-Ascorbic Acid, pubmed-meshheading:15026084-Catalase, pubmed-meshheading:15026084-Glutathione, pubmed-meshheading:15026084-Glutathione Peroxidase, pubmed-meshheading:15026084-Leydig Cells, pubmed-meshheading:15026084-Lipid Peroxidation, pubmed-meshheading:15026084-Male, pubmed-meshheading:15026084-Oxidative Stress, pubmed-meshheading:15026084-RNA, Messenger, pubmed-meshheading:15026084-Rats, pubmed-meshheading:15026084-Rats, Sprague-Dawley, pubmed-meshheading:15026084-Superoxide Dismutase, pubmed-meshheading:15026084-Testis, pubmed-meshheading:15026084-Testosterone, pubmed-meshheading:15026084-Thiobarbituric Acid Reactive Substances, pubmed-meshheading:15026084-alpha-Tocopherol
pubmed:year
2004
pubmed:articleTitle
Aging alters the functional expression of enzymatic and non-enzymatic anti-oxidant defense systems in testicular rat Leydig cells.
pubmed:affiliation
Geriatric Research, Education and Clinical Center (GRECC-182 B), Department of Veterans Affairs Palo Alto Health Care System, and Department of Medicine, Stanford University School of Medicine, CA, USA.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.