Cyclooxygenases in rat Leydig cells: Effects of luteinizing hormone and aging

Haolin Chen, Lindi Luo, June Liu, Barry R Zirkin

Research output: Contribution to journalArticle

Abstract

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-α or IL-1β 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.

Original languageEnglish (US)
Pages (from-to)735-742
Number of pages8
JournalEndocrinology
Volume148
Issue number2
DOIs
StatePublished - Feb 2007

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Leydig Cells
Prostaglandin-Endoperoxide Synthases
Luteinizing Hormone
Testosterone
Gonadotrophs
Cyclooxygenase 2 Inhibitors
Cyclooxygenase 2
Protein Kinase Inhibitors
Cyclic AMP-Dependent Protein Kinases
Insulin-Like Growth Factor I
Interleukin-1
Proteins

ASJC Scopus subject areas

  • Endocrinology
  • Endocrinology, Diabetes and Metabolism

Cite this

Cyclooxygenases in rat Leydig cells : Effects of luteinizing hormone and aging. / Chen, Haolin; Luo, Lindi; Liu, June; Zirkin, Barry R.

In: Endocrinology, Vol. 148, No. 2, 02.2007, p. 735-742.

Research output: Contribution to journalArticle

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