HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 292/2/E577    most recent 00367.2006v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Aizawa, K. Articles by Mesaki, N. Search for Related Content PubMed PubMed Citation Articles by Aizawa, K. Articles by Mesaki, N.

Expression of steroidogenic enzymes and synthesis of sex steroid hormones from DHEA in skeletal muscle of rats

¹Graduate School of Comprehensive Human Sciences and ²Center for Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba, Ibaraki, Japan; and ³Department of Biology, Appalachian State University, Boone, North Carolina

Submitted 22 July 2006 ; accepted in final form 26 September 2006

The functional importance of sex steroid hormones (testosterone and estrogens), derived from extragonadal tissues, has recently gained significant appreciation. Circulating dehydroepiandrosterone (DHEA) is peripherally taken up and converted to testosterone by 3-hydroxysteroid 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 skeletal 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 findings are novel and important in that they provide the first evidence showing that skeletal muscles are capable of locally synthesizing sex steroid hormones from circulating DHEA or testosterone.

androgen; estrogen; dehydroepiandrosterone; 3-hydroxysteroid dehydrogenase; 17-hydroxysteroid dehydrogenase; aromatase cytochrome P-450

This article has been cited by other articles:

				K. Sato, M. Iemitsu, K. Aizawa, and R. Ajisaka Testosterone and DHEA activate the glucose metabolism-related signaling pathway in skeletal muscle Am J Physiol Endocrinol Metab, May 1, 2008; 294(5): E961 - E968. [Abstract] [Full Text] [PDF]

				K. Aizawa, M. Iemitsu, T. Otsuki, S. Maeda, T. Miyauchi, and N. Mesaki Sex differences in steroidogenesis in skeletal muscle following a single bout of exercise in rats J Appl Physiol, January 1, 2008; 104(1): 67 - 74. [Abstract] [Full Text] [PDF]

				S. Takeuchi, N. Mukai, T. Tateishi, and S. Miyakawa Production of sex steroid hormones from DHEA in articular chondrocyte of rats Am J Physiol Endocrinol Metab, July 1, 2007; 293(1): E410 - E415. [Abstract] [Full Text] [PDF]