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- Title
Ethinyl oestradiol administration in women suppresses synthesis of collagen in tendon in response to exercise.
- Authors
Hansen, Mette; Koskinen, Satu O.; Petersen, Susanne G.; Doessing, Simon; Frystyk, Jan; Flyvbjerg, Allan; Westh, Eva; Magnusson, S. Peter; Kjaer, Michael; Langberg, Henning
- Abstract
Women are at greater risk than men of sustaining certain kinds of injury and diseases of collagen-rich tissues. To determine whether a high level of oestradiol has an acute influence on collagen synthesis in tendons at rest and in response to exercise, one-legged kicking exercise was performed for 60 min at 67% of maximum power by healthy, young oral contraceptive (OC) users when circulating synthetic (ethinyl) oestradiol was high ( n= 11, HE-OC) and compared to similar women who had never used OCs when circulating endogenous oestrogen was low ( n= 12, LE-NOC). Interstitial fluid was collected 24 h post-exercise through microdialysis catheters placed anterior to the patellar tendon in both legs and subsequently analysed for the amino-terminal propeptide of type I collagen (PINP), a marker of tendon collagen synthesis. To determine the long-term effect of OC usage, patellar tendon cross-sectional area (CSA) was measured by magnetic resonance imaging (MRI). A lower exercise-induced increase in tendon collagen synthesis was observed in HE-OC than in LE-NOC (ΔPINP (mean ±s.e.m.) 1.5 ± 5.3 versus 24.2 ± 9.4 ng ml−1, P < 0.05). Furthermore, serum and the interstitial peritendinous tissue concentrations of insulin-like growth factor I (IGF-I) and IGF-binding proteins showed a reduced bioavailability in HE-OC compared with results in LE-NOC. No difference in patellar tendon CSA was observed between groups. In conclusion, the selective increase in tendon collagen synthesis in LE-NOC but not HE-OC 24 h post-exercise is consistent with the hypothesis that oestradiol inhibits exercise-induced collagen synthesis in human tendon. The mechanism behind this is either a direct effect of oestradiol, or an indirect effect via a reduction in levels of free IGF-I. However, the data did not indicate any long-term effect on tendon size associated with chronic OC use.
- Publication
Journal of Physiology, 2008, Vol 586, Issue 12, p3005
- ISSN
0022-3751
- Publication type
Article
- DOI
10.1113/jphysiol.2007.147348