scholarly journals Protein Kinase A-Dependent Cooperation between GATA and CCAAT/Enhancer-Binding Protein Transcription Factors Regulates Steroidogenic Acute Regulatory Protein Promoter Activity

Endocrinology ◽  
2002 ◽  
Vol 143 (10) ◽  
pp. 3935-3945 ◽  
Author(s):  
Jacques J. Tremblay ◽  
Frédéric Hamel ◽  
Robert S. Viger
Keyword(s):  
Transcription Factors ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Promoter Activity ◽  
Regulatory Protein ◽  
Steroidogenic Acute Regulatory Protein ◽  
Enhancer Binding Protein ◽  
Steroidogenic Acute Regulatory ◽  
Protein Transcription ◽  
Kinase A

scholarly journals Luteinizing Hormone-Induced Extracellular-Signal Regulated Kinase Activation Differently Modulates Progesterone and Androstenedione Production in Bovine Theca Cells

Endocrinology ◽  
2005 ◽  
Vol 146 (7) ◽  
pp. 2903-2910 ◽  
Author(s):  
Kimihisa Tajima ◽  
Kumiko Yoshii ◽  
Shin Fukuda ◽  
Makoto Orisaka ◽  
Kaoru Miyamoto ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Regulatory Protein ◽  
Steroidogenic Acute Regulatory Protein ◽  
Mrna Levels ◽  
Theca Cells ◽  
Progesterone Production ◽  
Erk Phosphorylation ◽  
Steroidogenic Acute Regulatory ◽  
Kinase A

Abstract It has been reported that gonadotropins promoted phosphorylation of ERK/MAPK in granulosa cells. However, little is known about the effects of gonadotropin on ERK activity in theca cells. This study explores how LH/forskolin controls ERK phosphorylation in cultured bovine theca cells. Effects of ERK on steroidogenesis were also investigated. Phosphorylation of ERK in bovine theca cells was augmented by LH and forskolin in 5 min; it decreased thereafter below basal levels in 20 min. Nevertheless, phosphorylation of the ERK kinase, MEK, was unaffected. Addition of H89 (a protein kinase A inhibitor) significantly reduced the effect of LH/forskolin on ERK phosphorylation. A potent MEK inhibitor PD98059 eliminated ERK phosphorylation and augmented progesterone production concomitantly with the elevation of intracellular steroidogenic acute regulatory protein mRNA in LH/forskolin-stimulated theca cells. In contrast to progesterone production, androgen production was diminished significantly by inhibition of ERK with decreased intracellular P450c17 mRNA levels. Taking these results together, we conclude that LH/cAMP leads to phosphorylation of ERK in a biphasic manner through MEK-independent pathway in bovine theca cells. Protein kinase A-induced phosphatase could possibly contribute to the phosphorylation process. Furthermore, modulation of ERK phosphorylation involves control of thecal steroidogenesis via modulation of the expression of steroidogenic acute regulatory protein and P450c17.

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