Linked Life Data

17068133

Source:http://linkedlifedata.com/resource/pubmed/id/17068133

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2007-1-17
pubmed:abstractText
Previous studies suggested that increased Leydig cell cyclooxygenase (COX)2 expression may be involved in the reduced testosterone production that characterizes aged Leydig cells. Our objective herein was to further elucidate the relationships among LH stimulation, Leydig cell COX2 and COX1 expression, aging, and testosterone production. Incubation of Leydig cells from young or aged rats with LH or dibutyryl cAMP resulted in increases in both intracellular COX2 protein expression and testosterone production. COX1 expression did not respond to LH or dibutyryl cAMP. Incubation of adult cells with a protein kinase A inhibitor suppressed the stimulatory effects of LH on COX2 and testosterone production. Short-term incubation of Leydig cells with TGF-alpha or IL-1beta also increased COX2 protein levels; IGF-I had no effect. In vivo, LH also was found to stimulate both COX2 and testosterone, but not COX1. As reported previously, COX2 expression was greater in old than in young cells, and old Leydig cells responded to inhibition of COX2 in vitro with increased testosterone production. However, the effects of the COX2 inhibitors were not restricted to old cells; young Leydig cells also responded to COX2 inhibition with increased testosterone production. This and the observation that the incubation of young or old cells with LH resulted in increased COX2 and testosterone production in both cases suggests that the relationship between COX2 and testosterone production is not unique to aged Leydig cells. Moreover, the close correlation between increases in COX2 and testosterone in LH-stimulated young and aged Leydig cells is difficult to reconcile with the contention that the increased expression of COX2 in aged cells is responsible for age-related suppression of Leydig cell testosterone production.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0013-7227
pubmed:author
pubmed:issnType
Print
pubmed:volume
148
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
735-42
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Cyclooxygenases in rat Leydig cells: effects of luteinizing hormone and aging.
pubmed:affiliation
Department of Biochemistry and Molecular Biology, Division of Reproductive Biology, Johns Hopkins University Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, Maryland 21205, USA. hchen@jhsph.edu
pubmed:publicationType
Journal Article