Delay in post-ovariectomy estrogen-replacement negates estrogen-induced augmentation of post-exercise muscle satellite cell proliferation

Abstract

Aim: This study examined the effects of a delay in post-ovariectomy replacement of 17β-estradiol (estrogen) on the post-exercise proliferation of muscle satellite cells. Methods: Nine-week old, ovariectomized female Sprague-Dawley rats (n=64) were divided into eight groups based on: estrogen status (0.25 mg estrogen pellet or sham), exercise status (90 min run @ 17 m/min, -13.5° or unexercised) and estrogen replacement (“proximal”; estrogen replacement within two- weeks or “delayed”; estrogen replacement at eleven-weeks following ovariectomy). Results: Significant increases in satellite cells were found in the soleus and white gastrocnemius muscle (immunofluorescent co-localization of nuclei with Pax7) 72 hrs following eccentric exercise (p