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- Martinelle, N, et al.
(författare)
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Extracellular signal-regulated kinases are involved in the acute activation of steroidogenesis in immature rat Leydig cells by human chorionic gonadotropin
- 2004
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Ingår i: Endocrinology. - : The Endocrine Society. - 0013-7227 .- 1945-7170. ; 145:10, s. 4629-4634
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Tidskriftsartikel (refereegranskat)abstract
- We studied the involvement of the ERK cascade in human chorionic gonadotropin (hCG)-induced steroidogenesis by primary cultures of immature rat Leydig cells. Our findings indicate that protein kinase A and protein kinase C function as upstream kinases in connection with transduction of the signal from the gonadotropin receptor to the ERK cascade. These MAPKs enhance the stimulatory effects of hCG on the de novo synthesis of the steroidogenic acute regulatory protein and the activity of protein phosphatase 2A, which are associated with increased androgen production by the Leydig cell. Specific inhibition of ERK1/2 by Uo126 suppressed all of these cellular responses to hCG. In contrast, steroidogenesis from 22OHC (a cell-permeable form of cholesterol) is not inhibited by Uo126, suggesting that cholesterol delivery to mitochondria is being affected by this compound. We propose that the ERK cascade is an important part of the signal transduction pathway involved in the rapid hormonal responses of Leydig cells to trophic hormones. In hCG-activated Leydig cells, these MAPKs may play a role in controlling the biosynthesis of the steroidogenic acute regulatory protein as well as regulating protein phosphatase 2A activity, thereby governing cholesterol transport across the mitochondrial membrane.
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- Svechnikov, K, et al.
(författare)
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Interleukin-1alpha stimulates steroidogenic acute regulatory protein expression via p38 MAP kinase in immature rat Leydig cells
- 2003
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Ingår i: Journal of molecular endocrinology. - : Bioscientifica. - 0952-5041 .- 1479-6813. ; 30:1, s. 59-67
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated the involvement of the steroidogenic acute regulatory (StAR) protein in interleukin-1alpha (IL-1alpha)-induced steroidogenesis in immature (40-day-old) and adult Leydig cells in vitro. Further, IL-1alpha-mediated signaling pathway(s) controlling StAR expression in immature Leydig cells were also studied. IL-1alpha stimulated both androgen production and StAR protein expression in a dose- and time-dependent manner in immature but not adult Leydig cells. These effects of IL-1alpha were prevented by pretreatment of the cells with the specific inhibitors of the p38 MAP kinase, SB203580 and PD169316, suggesting that this kinase is an important part of IL-1alpha signaling in the immature Leydig cell. The present results suggest that IL-1alpha, which is constitutively produced by the rat testis from postnatal day 25, is an important paracrine regulator of postnatal Leydig cell maturation. Regulation of StAR protein expression is one of the possible mechanisms by which IL-1alpha contributes to the differentiation of immature Leydig cells into adult cells.
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