title: The role of estrogen receptor-α in estrogen-mediated regulation of basal and exercise-induced Hsp70 and Hsp27 expression in rat soleus.
abstract: We examined the influence of estrogen receptor-alpha (ERα) activation on estrogen-mediated regulation of heat shock proteins 70 (Hsp70) and 27 (Hsp27) in soleus. Ovariectomized rats received estrogen (EST), an ERα agonist (propyl pyrazole triol, PPT), both (EST+PPT), or a sham, and they served as either unexercised controls or were subjected to exercise by having to run downhill (17 m/min, -13.5° grade) for 90 min. At 72 h postexercise, soleus muscles were removed and either immunohistochemically stained for Hsp70 and myosin heavy chain or homogenized for Western blotting for Hsp70 and Hsp27. Elevated (p < 0.05) basal Hsp70 in both type I and II fibres in the unexercised EST, PPT, and EST+PPT groups relative to unexercised sham animals was noted. Compared with Hsp70 levels in the unexercised animals, that in exercised animals was elevated (p < 0.05) in both sham and PPT groups but not in EST and EST+PPT groups. Western blot determined that Hsp27 levels were not significantly different between groups. Hence, the ability of estrogen to augment resting type I and type II muscle fibre Hsp70 content is primarily mediated via muscle ERα. However, the blunted Hsp70 response following damaging exercise in estrogen-supplemented animals does not appear to be fully accounted for by ERα-mediated effects.
authors.forename: Eric
authors.initials: E
authors.lastname: Bombardier
authors.forename: Chris
authors.initials: C
authors.lastname: Vigna
authors.forename: Darin
authors.initials: D
authors.lastname: Bloemberg
authors.forename: Joe
authors.initials: J
authors.lastname: Quadrilatero
authors.forename: Peter M
authors.initials: PM
authors.lastname: Tiidus
authors.forename: A Russell
authors.initials: AR
authors.lastname: Tupling
mesh_terms: D000818:Animals; D015153:Blotting, Western; D047628:Estrogen Receptor alpha / Q000187:drug effects* / Q000378:metabolism; D015914:Estrogen Replacement Therapy; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D005455:Fluorescent Antibody Technique; D055551:HSP27 Heat-Shock Proteins / Q000378:metabolism*; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D009119:Muscle Contraction; D018656:Muscle Fibers, Fast-Twitch / Q000187:drug effects / Q000378:metabolism; D018657:Muscle Fibers, Slow-Twitch / Q000187:drug effects / Q000378:metabolism; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism; D010052:Ovariectomy; D010636:Phenols; D005082:Physical Exertion; D011720:Pyrazoles / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012420:Running; D013997:Time Factors
chemical_list: D047628:Estrogen Receptor alpha; D004967:Estrogens; D055551:HSP27 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; C486114:Hspb1 protein, rat; D010636:Phenols; D011720:Pyrazoles; C486184:4,4',4''-(4-propyl-((1)H)-pyrazole-1,3,5-triyl) tris-phenol