TY - JOUR
T1 - Müllerian inhibiting substance blocks the protein kinase A-induced expression of cytochrome P450 17α-hydroxylase/C17-20 lyase mRNA in a mouse Leydig cell line independent of cAMP responsive element binding protein phosphorylation
AU - Matt Laurich, V.
AU - Trbovich, Alexander M.
AU - O'Neill, Francis H.
AU - Houk, Christopher P.
AU - Sluss, Patrick M.
AU - Payne, Anita H.
AU - Donahoe, Patricia K.
AU - Teixeira, Jose
PY - 2002/9
Y1 - 2002/9
N2 - Müllerian inhibiting substance (MIS) is produced by fetal Sertoli cells and causes regression of the Müllerian duct in male fetuses shortly after commitment of the bipotential embryonic gonad to testes differentiation. MIS is also produced by the Sertoli cells and granulosa cells of the adult gonads where it plays an important role in regulating steroidogenesis. We have previously shown that MIS can dramatically reduce testosterone synthesis in Leydig cells by inhibiting the expression of cytochrome P450 17α-hydroxylase/C17-20 lyase (Cyp17) mRNA in vitro and in vivo. To characterize the signal transduction pathway used by MIS to control expression of endogenous Cyp17 in a mouse Leydig cell line, we demonstrate that MIS inhibits both LH- and cAMP-induced expression of Cyp17 at concentrations as low as 3.5 nM and for as long as 18 h. The induction of steroidogenic acute regulatory protein (STAR) mRNA by cAMP, however, was slightly increased by addition of MIS. Protein kinase A (PKA) inhibition with H-89 blocked Cyp17 mRNA induction, suggesting that MIS interferes with the PKA signal transduction pathway. Inhibition of Cyp17 induction was not seen with added U0126, and wortmannin inhibited the induction incompletely. In addition, phosphorylation of the cAMP responsive element binding protein (CREB) was not detected following 50 μM cAMP exposure, a concentration sufficient for Cyp17 mRNA induction. Moreover, CREB phosphorylation, which was observed with addition of 500 μM cAMP, was not inhibited by coincubation with MIS. Taken together, these results suggest that cAMP induces expression of Cyp17 by a PKA-mediated mechanism and that this induction, which is inhibited by MIS signal transduction, does not require CREB activity, and is distinct from that used to induce steroidogenic acute regulatory protein expression.
AB - Müllerian inhibiting substance (MIS) is produced by fetal Sertoli cells and causes regression of the Müllerian duct in male fetuses shortly after commitment of the bipotential embryonic gonad to testes differentiation. MIS is also produced by the Sertoli cells and granulosa cells of the adult gonads where it plays an important role in regulating steroidogenesis. We have previously shown that MIS can dramatically reduce testosterone synthesis in Leydig cells by inhibiting the expression of cytochrome P450 17α-hydroxylase/C17-20 lyase (Cyp17) mRNA in vitro and in vivo. To characterize the signal transduction pathway used by MIS to control expression of endogenous Cyp17 in a mouse Leydig cell line, we demonstrate that MIS inhibits both LH- and cAMP-induced expression of Cyp17 at concentrations as low as 3.5 nM and for as long as 18 h. The induction of steroidogenic acute regulatory protein (STAR) mRNA by cAMP, however, was slightly increased by addition of MIS. Protein kinase A (PKA) inhibition with H-89 blocked Cyp17 mRNA induction, suggesting that MIS interferes with the PKA signal transduction pathway. Inhibition of Cyp17 induction was not seen with added U0126, and wortmannin inhibited the induction incompletely. In addition, phosphorylation of the cAMP responsive element binding protein (CREB) was not detected following 50 μM cAMP exposure, a concentration sufficient for Cyp17 mRNA induction. Moreover, CREB phosphorylation, which was observed with addition of 500 μM cAMP, was not inhibited by coincubation with MIS. Taken together, these results suggest that cAMP induces expression of Cyp17 by a PKA-mediated mechanism and that this induction, which is inhibited by MIS signal transduction, does not require CREB activity, and is distinct from that used to induce steroidogenic acute regulatory protein expression.
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U2 - 10.1210/en.2001-211352
DO - 10.1210/en.2001-211352
M3 - Article
C2 - 12193547
AN - SCOPUS:0036720569
SN - 0013-7227
VL - 143
SP - 3351
EP - 3360
JO - Endocrinology
JF - Endocrinology
IS - 9
ER -