Stimulatory effect of progesterone on the expression of steroidogenic acute regulatory protein in MA-10 Leydig cells
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Stimulatory effect of progesterone on the expression of steroidogenic acute regulatory protein in MA-10 Leydig cells. / Schwarzenbach, Heidi; Manna, Pulak R; Stocco, Douglas M; Chakrabarti, Gopa; Mukhopadhyay, Amal K.
In: BIOL REPROD, Vol. 68, No. 3, 01.03.2003, p. 1054-63.Research output: SCORING: Contribution to journal › SCORING: Journal article › Research › peer-review
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T1 - Stimulatory effect of progesterone on the expression of steroidogenic acute regulatory protein in MA-10 Leydig cells
AU - Schwarzenbach, Heidi
AU - Manna, Pulak R
AU - Stocco, Douglas M
AU - Chakrabarti, Gopa
AU - Mukhopadhyay, Amal K
PY - 2003/3/1
Y1 - 2003/3/1
N2 - The steroidogenic acute regulatory protein (StAR), by virtue of its ability to facilitate the intramitochondrial transport of cholesterol, plays an important role in regulating steroid hormone biosynthesis in steroidogenic cells. In agreement with published data, both StAR expression and progesterone production in MA-10 mouse Leydig tumor cells could be stimulated with hCG and 8Br-cAMP. Addition of aminoglutethimide, an inhibitor of cholesterol side chain cleavage (P450(scc)) enzyme, not only resulted in a drastic inhibition of progesterone production but also in an attenuation of StAR expression in response to either hCG or 8-Br-cAMP. Therefore, we addressed the question of whether progesterone, the end product of the steroidogenic cascade in these cells, could be in a position to regulate the StAR gene expression. In MA-10 cells, we report here that progesterone in microgram amounts can induce StAR gene expression in a time- and dose-dependent manner. StAR expression in response to a maximally effective concentration of progesterone of 10 microg/ml was highest at 6 h and started decreasing thereafter. The effect of progesterone on StAR protein and StAR mRNA induction was mimicked by its synthetic analog, progestin R5020, but not by other steroids, including dexamethasone, estradiol, testosterone, and dihydrotestosterone. Dexamethasone, in contrast, was able to inhibit StAR expression in MA-10 cells. Surprisingly, RU486, a potent antagonist of progesterone and glucocorticoid action, had a stimulatory effect on StAR mRNA levels. Reverse transcription-polymerase chain reaction analysis demonstrated the absence of the classical form of progesterone receptor in MA-10 cells. Thus, for the first time, a direct stimulatory effect of a steroid on StAR gene expression has been demonstrated. Furthermore, these results provide a new insight, indicating that progesterone mediates the activation of StAR expression exerted presumably through a novel, nonclassical progesterone receptor in mouse Leydig cells.
AB - The steroidogenic acute regulatory protein (StAR), by virtue of its ability to facilitate the intramitochondrial transport of cholesterol, plays an important role in regulating steroid hormone biosynthesis in steroidogenic cells. In agreement with published data, both StAR expression and progesterone production in MA-10 mouse Leydig tumor cells could be stimulated with hCG and 8Br-cAMP. Addition of aminoglutethimide, an inhibitor of cholesterol side chain cleavage (P450(scc)) enzyme, not only resulted in a drastic inhibition of progesterone production but also in an attenuation of StAR expression in response to either hCG or 8-Br-cAMP. Therefore, we addressed the question of whether progesterone, the end product of the steroidogenic cascade in these cells, could be in a position to regulate the StAR gene expression. In MA-10 cells, we report here that progesterone in microgram amounts can induce StAR gene expression in a time- and dose-dependent manner. StAR expression in response to a maximally effective concentration of progesterone of 10 microg/ml was highest at 6 h and started decreasing thereafter. The effect of progesterone on StAR protein and StAR mRNA induction was mimicked by its synthetic analog, progestin R5020, but not by other steroids, including dexamethasone, estradiol, testosterone, and dihydrotestosterone. Dexamethasone, in contrast, was able to inhibit StAR expression in MA-10 cells. Surprisingly, RU486, a potent antagonist of progesterone and glucocorticoid action, had a stimulatory effect on StAR mRNA levels. Reverse transcription-polymerase chain reaction analysis demonstrated the absence of the classical form of progesterone receptor in MA-10 cells. Thus, for the first time, a direct stimulatory effect of a steroid on StAR gene expression has been demonstrated. Furthermore, these results provide a new insight, indicating that progesterone mediates the activation of StAR expression exerted presumably through a novel, nonclassical progesterone receptor in mouse Leydig cells.
KW - 8-Bromo Cyclic Adenosine Monophosphate
KW - Aminoglutethimide
KW - Animals
KW - Blotting, Northern
KW - Dexamethasone
KW - Enzyme Inhibitors
KW - Female
KW - Gene Expression Regulation
KW - Glucocorticoids
KW - Leydig Cell Tumor
KW - Mice
KW - Mifepristone
KW - Phosphoproteins
KW - Progesterone
KW - Progesterone Congeners
KW - Promegestone
KW - RNA, Messenger
KW - Receptors, Glucocorticoid
KW - Receptors, Progesterone
KW - Reverse Transcriptase Polymerase Chain Reaction
KW - Tumor Cells, Cultured
M3 - SCORING: Journal article
C2 - 12604660
VL - 68
SP - 1054
EP - 1063
JO - BIOL REPROD
JF - BIOL REPROD
SN - 0006-3363
IS - 3
ER -