Follicle-stimulating hormone-induced aromatase in immature rat Sertoli cells requires an active phosphatidylinositol 3-kinase pathway and is inhibited via the mitogen-activated protein kinase signaling pathway.
Postnatal development and function of testicular Sertoli cells are regulated primarily by FSH. During this early period of development, estrogens play a role in proliferation of somatic cells, which contributes significantly to testicular development. Growth factors like epidermal growth factor (EGF) are produced in the testis and play a role in regulation of estradiol production and male fertility. Although these divergent factors modulate gonadal function, little is known about their mechanism of action in Sertoli cells. The present study investigates the intracellular events that take place down-stream of FSH and EGF receptors in Sertoli cells isolated from immature (10-d-old) rats, and examines which intracellular signals may be involved in their effects on aromatase activity and estradiol production in immature rat Sertoli cells. Primary cultures of rat Sertoli cells were treated with FSH in combination with EGF and signaling pathway-specific inhibitors. Levels of estradiol production, aromatase mRNA (Cyp19a1), and aromatase protein (CYP19A1) were determined. Western blot analysis was performed to determine the effects of FSH and EGF on levels of activated (phosphorylated) AKT1 and p42 ERK2 and p44 ERK1, also named MAPK1 and MAPK3, respectively. The stimulatory actions of FSH on aromatase mRNA, aromatase protein, and estradiol production were blocked by inhibition of the phosphatidylinositol 3-kinase/AKT1 signaling pathway. In contrast, inhibition of ERK signaling augmented the stimulatory effects of FSH on estradiol production, aromatase mRNA, and protein levels. Furthermore, EGF inhibited the expression of aromatase mRNA and protein in response to FSH, and these inhibitory effects of EGF were critically dependent on the activation of the ERK signaling pathway. We conclude that an active phosphatidylinositol 3-kinase /AKT signaling pathway is required for the stimulatory actions of FSH, whereas an active ERK/MAPK pathway inhibits estradiol production and aromatase expression in immature Sertoli cells.
McDonald
Claudia A
CA
Olson Center for Women's Health, Department of Obstetrics and Gynecology, 983255 Nebraska Medical Center, University of Nebraska Medical Center, Omaha, Nebraska 68198-3255, USA.
Millena
Ana C
AC
Reddy
Sheila
S
Finlay
Sheila
S
Vizcarra
Jorge
J
Khan
Shafiq A
SA
Davis
John S
JS
D000818:Animals; D001141:Aromatase / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D002867:Chromones / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000378:metabolism / Q000494:pharmacology; D004958:Estradiol / Q000378:metabolism; D005419:Flavonoids / Q000494:pharmacology; D005640:Follicle Stimulating Hormone / Q000378:metabolism* / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D048369:MAP Kinase Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D020935:MAP Kinase Signaling System; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000378:metabolism; D009025:Morpholines / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000187:drug effects / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D012708:Sertoli Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D015398:Signal Transduction
D001141:Aromatase; D002867:Chromones; D004791:Enzyme Inhibitors; D004815:Epidermal Growth Factor; D004958:Estradiol; D005419:Flavonoids; D005640:Follicle Stimulating Hormone; D048369:MAP Kinase Kinase 1; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D009025:Morpholines; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one