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This Article Full Text Full Text (PDF) All Versions of this Article: 90/1/87    most recent expphysiol.2004.028373v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal 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 Google Scholar Google Scholar Articles by Piccone, C. M. Articles by McCormick, K. M. Search for Related Content PubMed PubMed Citation Articles by Piccone, C. M. Articles by McCormick, K. M. Related Collections Muscle

¹ Department of Exercise and Nutrition Sciences, University at Buffalo, State University of New York, Buffalo, NY 14214, USA Departments of ² Pharmacy Practice and Pharmaceutical Sciences, University at Buffalo, State University of New York, Amherst, NY 14260, USA

This study examined the effect of oestrogen deprivation and replacement on plantaris muscle size and myosin heavy chain (MHC) isoform composition in rats during a period of physiological growth. Seven-week-old female Sprague–Dawley rats were assigned to one of the three treatment groups: (1) control animals (Sham); (2) ovariectomized animals without oestrogen replacement (OVX/CO); and (3) ovariectomized animals with 17ß-oestradiol replacement (OVX/E₂). OVX/CO and OVX/E₂ animals were pair-fed with Sham animals to rule out the potentially confounding effects of differences in food intake and weight gain. Rats were killed 4 weeks after surgery and the plantaris muscle was removed for analysis. Ovariectomy had no effect on muscle fibre size, but reduced the relative amount of type IIx MHC. This was reversed with oestrogen replacement, suggesting that the reduction in type IIx MHC expression was an oestrogen-mediated effect. Oestrogen replacement reduced type IIb MHC expression and fast muscle fibre size. Changes in fast fibre size and type IIb MHC expression were not seen with ovariectomy, indicating that these changes were not simply due to the presence of oestrogen in the ovariectomized, oestrogen-replaced animals. These results suggest that another ovarian hormone may counteract the effect of oestrogen on fast fibre size and type IIb MHC expression in intact animals.

(Received 28 June 2004; accepted after revision 21 September 2004; first published online 4 October 2004)
Corresponding author K. M. McCormick: Department of Exercise and Nutrition Sciences, University at Buffalo, State University at New York, Buffalo, NY 14214, USA. Email: kmccorm{at}buffalo.edu

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				A. L. Moran, S. A. Nelson, R. M. Landisch, G. L. Warren, and D. A. Lowe Estradiol replacement reverses ovariectomy-induced muscle contractile and myosin dysfunction in mature female mice J Appl Physiol, April 1, 2007; 102(4): 1387 - 1393. [Abstract] [Full Text] [PDF]