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    Testosterone acts at the cell surface to induce granulosa/theca cell death via an apoptotic pathway in Atlantic croaker (Micropogonias undulatus)

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    Date
    2011-12
    Author
    Zhang, Chenan
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    Abstract
    The teleost ovarian follicle undergoes extensive remodeling and regression during the reproductive cycle—a process involving apoptosis and cell death. However, the hormonal regulation of these processes remains unclear. In the current study the role of testosterone in regulating regression of Atlantic croaker (Micropogonias undulatus) ovarian follicles was investigated in co-cultured granulosa/theca (G/T) cells. Testosterone (T) treatment enhanced serum starvation-induced cell death and apoptosis of G/T cells during the mature stage of oocyte maturation. This effect was mimicked by a cell-impermeable T conjugate, T-bovine serum albumin, indicating that this androgen action is initiated at the cell surface. Mibolerone, a nuclear androgen receptor agonist, was ineffective in promoting apoptosis and cell death, which suggests that T actions are independent from the nuclear receptor. Together, the data suggests that T-induction of apoptosis and cell death are through a novel membrane androgen receptor in the croaker ovary. T treatment also increased expression of a pro-apoptotic member of the Bcl-2 gene family, Bax, and two Bax upstream regulators, JNK and p53. These results suggest that T induces cell death of G/T cells in croaker through the apoptotic pathway involving JNK, p53 and Bax. An opposite response of cell death protection by T was also observed in G/T cells cultured from late-stage ovaries. This response was accompanied by a rapid increased ERK-1/-2 phosphorylation not seen in Mibolerone treatment. By examining the role of T in croaker follicle cell death and elucidating the corresponding basic mechanisms of androgen action, we are learning more about the regulatory components involved in the breakdown and remodeling stages of the teleost reproductive cycle.
    Department
    Marine Science
    Description
    text
    Subject
    Androgen
    Apoptosis
    Cell death
    Membrane androgen receptor
    Ovary
    Teleost
    Testosterone
    Bax
    URI
    http://hdl.handle.net/2152/ETD-UT-2011-12-4903
    http://hdl.handle.net/2152/23902
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    • facebook
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    • CONTACT US
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    • Emergency Information
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    © The University of Texas at Austin