This Article Full Text (PDF) References 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 PubMed Alert me to new issues of the journal Add to Saved Citations Download to citation manager Request Permissions Request Reprints Add to My Marked Citations Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Citing Articles via Scopus Google Scholar Articles by Schneider, B. St. P. Articles by Tiidus, P. M. Search for Related Content PubMed PubMed Citation Articles by Schneider, B. St. P. Articles by Tiidus, P. M. Pubmed/NCBI databases Compound via MeSH Substance via MeSH Hazardous Substances DB ESTRADIOL PROGESTERONE Social Bookmarking                         What's this?

The Effects of Estradiol and Progesterone on Plantarflexor Muscle Fatigue in Ovariectomized Mice

University of Wisconsin-Madison School of Nursing, bsschneider{at}wisc.edu

Jason P. Fine, PhD

University of Wisconsin-Madison, Department of Biostatistics

Timothy Nadolski, BS

University of Wisconsin-Madison School of Nursing

Peter M. Tiidus, PhD

Wilfrid Laurier University, Department of Kinesiology and Physical Education, Waterloo, Ontario, Canada

The aim of this study was to examine specific and interactional effects of estradiol and progesterone on the time-to-fatigue of eccentrically contracted plantarflexor muscles and on the percent of plantarflexor isometric torque remaining immediately after an eccentric contraction (EC) protocol. Ovariectomized 6- to 8-week-old C57BL/6 mice were implanted with 21-day 0.05 mg-placebo, 0.05 mg-17-ß estradiol (OE), 15 mg-progesterone (OP), or estradiol and progesterone pellets (OEP). On the 16th day of hormone treatment, the isometric torque of the left plantarflexor muscles was measured. The left plantarflexor muscles then underwent 1 set of 150 ECs followed by 2 immediate post-EC isometric torque measurements. A group of ovarian-intact female mice of a similar age underwent the same isometric torque measurements and EC protocol. Plantarflexor muscle fatigue during ECs took 30%-41% longer to occur in the OP group (n = 9) than it did in the intact (n =8, P = 0.02), OC (n = 11, P = 0.003), and OEP (n =9, P = 0.007) groups. Peak active isometric torque had decreased immediately after ECs at 2 time points (M1 and M2). The OP group exhibited the greatest percent of isometric torque remaining immediately after ECs (M1, P = 0.03; M2, P = 0.04). These findings suggest that progesterone reduces muscle fatigue in response to ECs and that this progesterone effect is blunted when estradiol also is present. Therefore, ovarian hormone status may need to be considered when evaluating a response to physical activities, especially those activities involving ECs.

Key Words: eccentric exercise • isometric torque • skeletal muscle • time-to-fatigue

Biological Research For Nursing, Vol. 5, No. 4, 265-275 (2004)
DOI: 10.1177/1099800403262258


CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				S. M. Greising, K. A. Baltgalvis, D. A. Lowe, and G. L. Warren Hormone Therapy and Skeletal Muscle Strength: A Meta-Analysis J Gerontol A Biol Sci Med Sci, October 1, 2009; 64A(10): 1071 - 1081. [Abstract] [Full Text] [PDF]

				P M Tiidus Can oestrogen influence skeletal muscle damage, inflammation, and repair? Br. J. Sports Med., May 1, 2005; 39(5): 251 - 253. [Full Text] [PDF]