Expression Of Steroidogenic Enzymes And Synthesis Of Sex Steroid Hormones From DHEA In Skeletal Muscle Of Rats

ASU Author/Contributor (non-ASU co-authors, if there are any, appear on document)
Dr.. Chishimba Nathan Mowa, Associate Professor (Creator)
Appalachian State University (ASU )
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Abstract: The functional importance of sex steroid hormones (testosterone and estrogens), derived from extragonadal tissues, has recently gained signi?cant appreciation. Circulating dehydroepiandrosterone (DHEA) is peripherally taken up and converted to testosterone by 3-hydrox-ysteroid dehydrogenase (HSD) and 17-HSD, and testosterone in turn is irreversibly converted to estrogens by aromatase cytochrome P-450 (P450arom). Although sex steroid hormones have been implicated in skeletal muscle regulation and adaptation, it is unclear whether skel-etal muscles have a local steroidogenic enzymatic machinery capable of metabolizing circulating DHEA. Thus, here, we investigate whether the three key steroidogenic enzymes (3-HSD, 17-HSD, and P450arom) are present in the skeletal muscle and are capable of generating sex steroid hormones. Consistent with our hypothesis, the present study demonstrates mRNA and protein expression of these enzymes in the skeletal muscle cells of rats both in vivo and in culture (in vitro). Importantly, we also show an intracellular formation of testosterone and estradiol from DHEA or testosterone in cultured muscle cells in a dose-dependent manner. These ?ndings are novel and important in that they provide the ?rst evidence showing that skeletal muscles are capable of locally synthesizing sex steroid hor-mones from circulating DHEA or testosterone.

Additional Information

Katsuji Aizawa, Motoyuki Iemitsu, Seiji Maeda, Subrina Jesmin, Takeshi Otsuki, Chishimba N. Mowa, Takashi Miyauchi and Noboru Mesaki (2007) "Expression Of Steroidogenic Enzymes And Synthesis Of Sex Steroid Hormones From DHEA In Skeletal Muscle Of Rats." American Journal of Physiology, Endocrinology and Metabolism #292 Version of Record Available [DOI:10.1152/ajpendo.00367.2006]
Language: English
Date: 2007
androgen, estrogen, dehydroepiandrosterone, 3-hydroxysteroid de-hydrogenase, 17-hydroxysteroid dehydrogenase, aromatase cyto-chrome P-450

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