title: No effect of short-term 17beta-estradiol supplementation in healthy men on systemic inflammatory responses to exercise.
abstract: Sex-based differences in inflammatory responses to exercise may be mediated by estrogen through increased muscle membrane stability and/or inhibited cytokine production. In this study, in vivo effects of estrogen on systemic inflammation-related responses to exercise were assessed in healthy men. In a double-blind, placebo-controlled, crossover design, 11 men cycled for 90 min at 65% Vo2 max after 8 days of 17beta-estradiol supplementation (ES; 2 mg/day) or placebo (PL; glucose polymer). After a 2-wk washout, exercise was repeated after 8 days on the alternate treatment. Blood was collected pre- and postexercise to determine IL-6, soluble intercellular adhesion molecule-1 (sICAM-1), neutrophil counts, and cortisol. Preexercise serum was assayed for sex hormones. ES increased estradiol (133+/-71 to 840+/-633 pmol/l, P=0.005) and reduced testosterone (19.9+/-3.7 to 16.1+/-3.9 nmol/l, P=0.007). Exercise increased cortisol (P=0.02), IL-6 (P<0.001) and neutrophil counts (P<0.001) with no influence on sICAM-1 (P=0.34) and no effect of ES on these changes. Postexercise IL-6 and neutrophil counts were correlated (r=0.58, P=0.005); postexercise IL-6 and cortisol (r=0.18, P=0.43) and postexercise cortisol and neutrophil counts (r=0.06, P=0.78) were not. Postexercise sICAM-1 was not correlated with the above variables (P>or=0.79). In conclusion, 8 days of ES in healthy men did not influence systemic inflammation-related responses to acute exercise. Future studies should investigate 17beta-estradiol effects on IL-6 production and neutrophil infiltration within skeletal muscle during and after exercise.
authors.affiliation: Children's Exercise and Nutrition Center, Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada L8N 3Z5.
authors.forename: Brian W
authors.initials: BW
authors.lastname: Timmons
authors.forename: Mazen J
authors.initials: MJ
authors.lastname: Hamadeh
authors.forename: Mark A
authors.initials: MA
authors.lastname: Tarnopolsky
mesh_terms: D000328:Adult; D004958:Estradiol / Q000494:pharmacology*; D015444:Exercise; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D007249:Inflammation / Q000276:immunology / Q000378:metabolism*; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism*; D015850:Interleukin-6 / Q000378:metabolism*; D007958:Leukocyte Count; D008297:Male; D009504:Neutrophils / Q000187:drug effects; D011374:Progesterone / Q000097:blood; D013739:Testosterone / Q000097:blood
chemical_list: D015850:Interleukin-6; D018799:Intercellular Adhesion Molecule-1; D013739:Testosterone; D011374:Progesterone; D004958:Estradiol; D006854:Hydrocortisone