scholarly journals Interleukin-1alpha stimulates steroidogenic acute regulatory protein expression via p38 MAP kinase in immature rat Leydig cells

2003 ◽  
Vol 30 (1) ◽  
pp. 59-67 ◽  
Author(s):  
K Svechnikov ◽  
DM Stocco ◽  
O Soder
Keyword(s):  
Protein Expression ◽  
Map Kinase ◽  
Leydig Cell ◽  
Leydig Cells ◽  
Regulatory Protein ◽  
P38 Map Kinase ◽  
Dependent Manner ◽  
Star Protein ◽  
Adult Leydig Cells ◽  
Steroidogenic Acute Regulatory

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.

scholarly journals Diametric Effects of Bacterial Endotoxin Lipopolysaccharide on Adrenal and Leydig Cell Steroidogenic Acute Regulatory Protein

Endocrinology ◽  
2000 ◽  
Vol 141 (11) ◽  
pp. 4000-4012 ◽  
Author(s):  
Karen Held Hales ◽  
Thorsten Diemer ◽  
Salil Ginde ◽  
Birinder K. Shankar ◽  
Maretha Roberts ◽  
...  
Keyword(s):  
Messenger Rna ◽  
Leydig Cells ◽  
Regulatory Protein ◽  
Serum Testosterone ◽  
Northern Analysis ◽  
Dependent Manner ◽  
Star Protein ◽  
Adrenal Steroidogenesis ◽  
Serum Lh ◽  
Steroidogenic Acute Regulatory

Abstract Immune activation results in the activation of adrenal steroidogenesis and inhibition of gonadal steroidogenesis. Previous studies indicated that these effects were caused primarily by activation and suppression of the secretion of ACTH and LH, respectively. However, other evidence indicated a direct effect of the immune system on the gonads. In this study, serum testosterone, quantitated by RIA after lipopolysaccharide injection, showed a significant decrease within 2 h. Parallel measurement of serum LH showed no change. There were no differences in LH receptor or cAMP produced in Leydig cells between vehicle- and lipopolysaccharide-injected mice. The 30-kDa form of the steroidogenic acute regulatory (StAR) protein was quantitated, by Western blot, in Leydig cells and was found to decrease in a time-dependent manner. No change in StAR protein messenger RNA (mRNA) was detected by Northern analysis during this time, nor were any changes found in the levels of mRNA for the steroidogenic enzymes P450scc, 3β-hydroxysteroid dehydrogenaseΔ 4-Δ5-isomerase, or P450c17. In the adrenal, StAR protein was increased, as was StAR protein mRNA. No changes were observed in the levels of mRNA for P450scc, 3β-hydroxysteroid dehydrogenaseΔ 4-Δ5-isomerase, or P450c21. Thus, although the mechanisms of regulation differ, changes in the levels of StAR protein are a sensitive indicator of the steroidogenic capacity of these two tissues.

scholarly journals Inhibition of Cyclooxygenase-2 Activity Enhances Steroidogenesis and Steroidogenic Acute Regulatory Gene Expression in MA-10 Mouse Leydig Cells

Endocrinology ◽  
2003 ◽  
Vol 144 (8) ◽  
pp. 3368-3375 ◽  
Author(s):  
XingJia Wang ◽  
Matthew T. Dyson ◽  
Youngah Jo ◽  
Douglas M. Stocco
Keyword(s):  
Gene Expression ◽  
Protein Expression ◽  
Leydig Cells ◽  
Promoter Activity ◽  
Regulatory Gene ◽  
Steroid Production ◽  
Star Protein ◽  
Cox Inhibitor ◽  
Steroidogenic Acute Regulatory ◽  
Star Gene

Abstract To study the mechanism for the regulatory effect of arachidonic acid (AA) on steroidogenesis, the role of cyclooxygenase (COX) in steroid production and steroidogenic acute regulatory (StAR) gene expression was investigated. Although stimulation with 0.05 mm dibutyryl cAMP (Bt2cAMP) did not increase StAR protein or progesterone in MA-10 mouse Leydig cells, the addition of 1 μm of the COX inhibitor indomethacin increased StAR protein expression and progesterone production by 5.7-fold and 34.3-fold, respectively. In the presence of indomethacin, the level of Bt2cAMP required for maximal steroidogenesis was reduced from 1.0 mm to 0.25 mm. Similar results were obtained in studies on StAR promoter activity and in Northern blot analyses of StAR mRNA expression, suggesting that inhibition of COX activity enhanced StAR gene transcription. COX2 (an inducible isoform of COX) was constitutively detected in MA-10 cells. Although SC560, a selective COX1 inhibitor, did not affect steroidogenesis, the COX2 inhibitor NS398 significantly enhanced Bt2cAMP-stimulated StAR protein expression and steroid production. Overexpression of the COX2 gene in COS-1 cells significantly inhibited StAR promoter activity. The results of the present study suggest that inhibition of COX2 activity increases the sensitivity of steroidogenesis to cAMP stimulation in MA-10 Leydig cells.

scholarly journals Cyclic AMP-induced expression of steroidogenic acute regulatory protein is dependent upon phosphoprotein phosphatase activities

2000 ◽  
Vol 24 (2) ◽  
pp. 233-239 ◽  
Author(s):  
PM Jones ◽  
SB Sayed ◽  
SJ Persaud ◽  
CJ Burns ◽  
S Gyles ◽  
...  
Keyword(s):  
Cyclic Amp ◽  
Protein Expression ◽  
Regulatory Protein ◽  
Steroid Production ◽  
Phosphoprotein Phosphatase ◽  
Star Protein ◽  
Site Of Action ◽  
Dependent Protein ◽  
Steroidogenic Acute Regulatory

In addition to the well-documented role of protein kinases in the regulation of steroid production, phosphoprotein phosphatase (PP) activity is required for steroidogenesis. In the present study, we have used the mouse Y1 adrenocortical cell line to identify the site of action of PPs on steroid production by measuring the effects of PP inhibition on the expression of the steroidogenic acute regulatory (StAR) protein and on steroid production. Forskolin-induced activation of cyclic AMP-dependent protein kinase (PKA) enhanced steroidogenesis and this was accompanied by an increased expression of StAR protein. Both steroidogenesis and StAR protein expression were inhibited by two structurally dissimilar inhibitors of PP1 and PP2A activities, okadaic acid and calyculin A. These results suggest that inhibition of PP1 and PP2A inhibits steroid production by preventing the expression of the StAR protein, implicating PP1/2A dephosphorylation reactions as important regulators of stimulus-dependent StAR protein expression, and thus of steroidogenesis.

scholarly journals Interleukin-1 inhibits Leydig cell steroidogenesis without affecting steroidogenic acute regulatory protein messenger ribonucleic acid or protein levels

1998 ◽  
Vol 156 (3) ◽  
pp. 461-467 ◽  
Author(s):  
T Lin ◽  
D Wang ◽  
DM Stocco
Keyword(s):  
Mrna Expression ◽  
Leydig Cell ◽  
Leydig Cells ◽  
Interleukin 1 ◽  
Mrna Level ◽  
Primary Cultures ◽  
Regulatory Protein ◽  
Steroidogenic Acute Regulatory Protein ◽  
Protein Levels ◽  
Steroidogenic Acute Regulatory

The rate-limiting step of steroidogenesis is the transport of the substrate cholesterol from the outer to the inner mitochondrial membrane which involves a cycloheximide-sensitive newly synthesized protein. A protein believed to carry out this function was recently cloned from MA-10 mouse Leydig tumor cells and named the steroidogenic acute regulatory protein (StAR). In the present study, we evaluated the expression and regulation of StAR in primary cultures of rat Leydig cells. StAR mRNA was expressed in Leydig cells as two major transcripts of 3.8 and 1.7 kb and one minor transcript of 1.2 kb. Induction of StAR mRNA transcripts could be detected as early as 30 min after the addition of human choriogonadotropin (hCG) with peak levels attained between 2 and 4 h. hCG in concentrations of 0.1-10 ng/ml caused a dose-dependent increase in StAR mRNA expression. hCG administered at a dose of 10 ng/ml increased the 3.8 kb StAR mRNA level about 14-fold and the 1.7 kb StAR mRNA level about 13.6-fold. hCG-stimulated StAR mRNA was associated with increased StAR protein levels as determined by immunoblot analysis (a 4.5-fold increase). Murine interleukin-1 alpha (mIL-1 alpha) at a concentration of 100 ng/ml inhibited hCG-induced cytochrome P450 side-chain cleavage (P450 scc) mRNA expression and testosterone formation almost completely. Interestingly, mIL-1 alpha had no effect on hCG-induced StAR mRNA or protein levels. Furthermore, mIL-1 alpha (10 ng/ml) decreased conversion of (22R)-hydroxycholesterol to testosterone while the conversion of pregnenolone, 17-hydroxypregnenolone, dehydroepiandrosterone and androstenedione to testosterone were not affected. These results indicate that the major inhibitory effect of IL-1 on Leydig cell function occurs at the level of P450 scc.

scholarly journals Chrysin, a natural flavonoid enhances steroidogenesis and steroidogenic acute regulatory protein gene expression in mouse Leydig cells

2008 ◽  
Vol 197 (2) ◽  
pp. 315-323 ◽  
Author(s):  
Kuladip Jana ◽  
Xiangling Yin ◽  
Randolph B Schiffer ◽  
Jau-Jiin Chen ◽  
Akhilesh K Pandey ◽  
...  
Keyword(s):  
Gene Expression ◽  
Leydig Cells ◽  
Steroid Hormone ◽  
Mrna Level ◽  
Regulatory Protein ◽  
Threshold Level ◽  
Star Protein ◽  
Chain Cleavage ◽  
Steroidogenic Acute Regulatory ◽  
Star Gene

During the aging process of males, testosterone biosynthesis declines in testicular Leydig cells resulting in decreases in various physiological functions. To explore the possibility of delaying the decline using food supplements, we have studied steroidogenic effects of a natural flavonoid, chrysin, in mouse Leydig cells. Chrysin dramatically increased cyclic AMP (cAMP)-induced steroidogenesis in MA-10 mouse Leydig tumor cells. This result was confirmed using Leydig cells isolated from mouse testes. The steroidogenic effect of chrysin is not associated with an increase in expression of the P450 side-chain cleavage enzyme, required for the conversion of cholesterol to pregnenolone. In addition, when 22(R)hydroxylcholesterol was used as a substrate, chrysin induced a non-significant increase in steroid hormone, suggesting that the majority of the observed increase in steroidogenesis was due to the increased supply of substrate cholesterol. These observations were corroborated by showing that chrysin induced a marked increase in the expression of steroidogenic acute regulatory (StAR) protein, the factor that controls mitochondrial cholesterol transfer. Also, chrysin significantly increased StAR promoter activity and StAR mRNA level. Further studies indicated that this compound depressed expression of DAX-1, a repressor in StAR gene transcription. In the absence of cAMP, chrysin did not increase steroidogenesis. However, when a sub-threshold level of cAMP was used, StAR protein and steroid hormone were increased by chrysin to the levels seen with maximal stimulation of cAMP. These results suggest that while chrysin itself is unable to induce StAR gene expression and steroidogenesis, it appears to function by increasing the sensitivity of Leydig cells to cAMP stimulation.

scholarly journals MAPK Phosphatase-1 (MKP-1) Expression Is Up-Regulated by hCG/cAMP and Modulates Steroidogenesis in MA-10 Leydig Cells

Endocrinology ◽  
2011 ◽  
Vol 152 (7) ◽  
pp. 2665-2677 ◽  
Author(s):  
Laura Brion ◽  
Paula M. Maloberti ◽  
Natalia V. Gomez ◽  
Cecilia Poderoso ◽  
Alejandra B. Gorostizaga ◽  
...  
Keyword(s):  
Hormonal Regulation ◽  
Leydig Cells ◽  
Map Kinases ◽  
Regulatory Gene ◽  
Regulatory Protein ◽  
Protein Accumulation ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Mapk Phosphatase ◽  
Steroidogenic Acute Regulatory

MAP kinases (MAPKs), such as ERK1/2, exert profound effects on a variety of physiological processes. In steroidogenic cells, ERK1/2 are involved in the expression and activation of steroidogenic acute regulatory protein, which plays a central role in the regulation of steroidogenesis. In MA-10 Leydig cells, LH and chorionic gonadotropin (CG) trigger transient ERK1/2 activation via protein kinase A, although the events that lead to ERK1/2 inactivation are not fully described. Here, we describe the hormonal regulation of MAPK phosphatase-1 (MKP-1), an enzyme that inactivates MAPKs, in MA-10 cells. In our experiments, human CG (hCG)/cAMP stimulation rapidly and transiently increased MKP-1 mRNA levels by a transcriptional action. This effect was accompanied by an increase in protein levels in both nuclear and mitochondrial compartments. In cells transiently expressing flag-MKP-1 protein, hCG/cAMP promoted the accumulation of the recombinant protein in a time-dependent manner (10-fold at 1 h). Moreover, hCG/cAMP triggered ERK1/2-dependent MKP-1 phosphorylation. The blockade of cAMP-induced MAPK kinase/ERK activation abated MKP-1 phosphorylation but only partially reduced flag-MKP-1 protein accumulation. Together, these results suggest that hCG regulates MKP-1 at transcriptional and posttranslational level, protein phosphorylation being one of the mechanisms involved in this regulation. Our study also demonstrates that MKP-1 overexpression reduces the effects of cAMP on ERK1/2 phosphorylation, steroidogenic acute regulatory gene promoter activity, mRNA levels, and steroidogenesis, whereas MKP-1 down-regulation by small interfering RNA produces opposite effects. In summary, our data demonstrate that hCG regulates MKP-1 expression at multiple stages as a negative feedback regulatory mechanism to modulate the hormonal action on ERK1/2 activity and steroidogenesis.

scholarly journals Cyclin-Dependent Kinase 5 Regulates Steroidogenic Acute Regulatory Protein and Androgen Production in Mouse Leydig Cells

Endocrinology ◽  
2008 ◽  
Vol 150 (1) ◽  
pp. 396-403 ◽  
Author(s):  
Ho Lin ◽  
Mei-Chih Chen ◽  
Chien-Te Ku
Keyword(s):  
Leydig Cells ◽  
Kinase Activity ◽  
Regulatory Protein ◽  
Protein A ◽  
Male Reproduction ◽  
Serine Phosphorylation ◽  
Cyclin Dependent Kinase ◽  
Star Protein ◽  
Steroidogenic Acute Regulatory ◽  
Cyclin Dependent Kinase 5

The roles of cyclin-dependent kinase 5 (Cdk5) in central nervous system and neurodegenerative diseases have been intensely investigated in recent decades. Because protein expressions of Cdk5 and its regulator, p35, have been identified in Leydig cells, it is informative to further explore the novel function of Cdk5/p35 in male reproduction. Here we show that Cdk5/p35 protein expression and kinase activity in mouse Leydig cells are regulated by human chorionic gonadotrophin (hCG) in both dose- and time-dependent manners. Blocking of Cdk5 by molecular inhibitors or small interfering RNA resulted in reduction of testosterone production by Leydig cells. cAMP, a second messenger in LH signaling, was identified as a factor in hCG-dependent regulation of Cdk5/p35. Importantly, Cdk5 protein and kinase activity could support accumulation of steroidogenic acute regulatory (StAR) protein, a crucial component of steroidogenesis. We additionally addressed the protein interaction between Cdk5/p35 and StAR. The Cdk5-dependent serine phosphorylation of StAR indicated a possible mechanism by which Cdk5 induced accumulation of StAR protein. In conclusion, Cdk5 modulates hCG-induced androgen production in mouse Leydig cells, possibly through regulation of StAR protein levels. These results indicate that Cdk5 may play an important role in male reproductive endocrinology and is a potential therapeutic target in androgen-related diseases. The physiological function of cyclin-dependent kinase 5 (Cdk5) in mouse Leydig cells is to regulate androgen production through stabilizing the steroiodogenic acute regulatory (StAR) protein.

Trimethyltin (TMT) Reduces Testosterone Production in Adult Leydig Cells in Rats

2019 ◽  
Vol 38 (6) ◽  
pp. 493-500 ◽  
Author(s):  
Derong Ma ◽  
Nengqin Luo ◽  
Guoqiang Xue
Keyword(s):  
Leydig Cell ◽  
Leydig Cells ◽  
Follicle Stimulating Hormone ◽  
Regulatory Protein ◽  
Cell Number ◽  
Severe Toxicity ◽  
Testosterone Production ◽  
Gene And Protein Expression ◽  
Adult Leydig Cells ◽  
Stimulating Hormone

Trimethyltin (TMT) is widely used as a plastic heat stabilizer and can cause severe toxicity. Here, the effects of TMT on testosterone production by adult Leydig cells and the related mechanisms of action were investigated. Eighteen adult male Sprague Dawley rats (56 days old) were randomly divided into 3 groups and given intraperitoneal injection of TMT for 21 consecutive days at the doses of 0 (vehicle control), 5, or 10 mg/kg/d. After treatment, trunk blood was collected for hormonal analysis. In addition, related gene and protein expression in testes was detected. At 10 mg/kg, TMT significantly reduced serum testosterone levels but increased serum luteinizing and follicle-stimulating hormone levels. The messenger RNA and protein levels of luteinizing hormone/chorionic gonadotropin receptor, steroidogenic acute regulatory protein, cytochrome P450 17-hydroxylase/17,20-lyase, follicle-stimulating hormone receptor, and SRY box 9 were significantly lower in the TMT-treated testes than in controls. Immunohistochemical study showed that TMT decreased adult Leydig cell number. In conclusion, these findings indicate that TMT reduced adult Leydig cell testosterone production in vivo by directly downregulating the expression of steroidogenic enzymes and decreasing adult Leydig cell number in the testis.

Sign in / Sign up

Export Citation Format

Share Document