Linked Life Data

3359978

Source:http://linkedlifedata.com/resource/pubmed/id/3359978

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1988-6-1
pubmed:abstractText
Glucocorticoids induce thymocyte cell death via mechanisms that occur in concert with internucleosomal DNA cleavage. To further study this process at the single cell level, glucocorticoid effects on rat thymocyte DNA were analyzed using fluorescence-activated flow cytometry. Thymocytes were isolated from adrenalectomized rats, treated in vitro with steroid hormones, stained with 0.1 mM acridine orange, and analyzed by flow cytometry. After 5 h of treatment with 10(-7) M dexamethasone a population of thymocytes with reduced acridine orange binding was observed. Thymocyte viability after glucocorticoid treatment was greater than 95%, indicating that the observed changes in dye binding occurred before cell death. Induction of this subpopulation of thymocytes was both time and steroid concentration dependent, being detectable within 2 h of in vitro steroid treatment. This response to glucocorticoids was blocked by the glucocorticoid receptor antagonist RU 486, indicating a steroid receptor-mediated process. Furthermore, both actinomycin D and cycloheximide blocked the appearance of this glucocorticoid effect, thus demonstrating a dependence upon RNA and protein biosynthesis, respectively. Incubation of thymocytes with inhibitors of DNA repair (aminobenzamide or methylnicotinamide) also diminished acridine orange binding to thymocytes. The effects of these DNA repair inhibitors and glucocorticoids were additive, suggesting independent mechanisms of action. Dexamethasone treatment (10(-7) M) of cells that fail to die in response to glucocorticoids (HeLa S3) had no effect on dye binding. These findings are consistent with the concept that glucocorticoids induce a lysis gene product that alters the thymocyte genome and thus leads to cell death.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0013-7227
pubmed:author
pubmed:issnType
Print
pubmed:volume
122
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2158-64
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
Analysis of glucocorticoid actions on rat thymocyte deoxyribonucleic acid by fluorescence-activated flow cytometry.
pubmed:affiliation
Department of Physiology, University of North Carolina, Chapel Hill 27514.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.