title: Salivary estradiol, interleukin-6 production, and the relationship to substrate metabolism during exercise in females.
abstract: Estradiol (E(2)) has been documented to have anti-inflammatory effects on the immune system. Interleukin-6 (IL-6), is classified as a "myokine", and has known metabolic consequences. Thus, the purpose of this study was to determine the effects of menstrual phase and exercise on the interaction of E(2) and IL-6, and the role of IL-6 in substrate metabolism. Ten female subjects completed three separate testing sessions: baseline evaluation, and 1 h of treadmill exercise at 65% of peak [Formula: see text] during both the midfollicular (MF) and midluteal (ML) menstrual phases. Saliva was collected prior to, during, and post-exercise for determination of E(2) and IL-6. Expired gases and an additional saliva sample were collected 30 min post-exercise. No significant differences were observed in any of the measured variables across menstrual phase. Exercise resulted in an acute rise in estradiol and IL-6; however, E(2) was not related to IL-6 at baseline or in response to exercise. IL-6 remained elevated at the end of exercise and was found to be related to energy expenditure from fat, and to total energy expenditure at 60 min, and 30 min post-exercise. No relationships were found between the anti-inflammatory estrogen E(2) and the cytokine IL-6. However, relationships were found between IL-6 and indices of substrate metabolism. Based on the data from the current research, IL-6 likely plays a metabolic role in healthy individuals during exercise when released from the muscle as a result of reduced energy availability, acting as a "myokine", in comparison to inflammation-induced IL-6 release.
authors.affiliation: Department of Exercise and Sport Science, University of Utah, 250 S. 1850 E. Rm 241 HPER N, Salt Lake City, UT 84112, USA. stephen.ives@utah.edu
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Ives
authors.forename: Mark
authors.initials: M
authors.lastname: Blegen
authors.forename: Mary A
authors.initials: MA
authors.lastname: Coughlin
authors.forename: Jan
authors.initials: J
authors.lastname: Redmond
authors.forename: Tracey
authors.initials: T
authors.lastname: Matthews
authors.forename: Vincent
authors.initials: V
authors.lastname: Paolone
mesh_terms: D000328:Adult; D016207:Cytokines / Q000097:blood; D004734:Energy Metabolism / Q000502:physiology*; D004958:Estradiol / Q000032:analysis / Q000097:blood / Q000378:metabolism*; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006728:Hormones / Q000097:blood; D006801:Humans; D015850:Interleukin-6 / Q000032:analysis / Q000097:blood / Q000378:metabolism*; D008597:Menstrual Cycle / Q000378:metabolism / Q000502:physiology; D012463:Saliva / Q000737:chemistry / Q000378:metabolism*; D012737:Sex Factors; D013997:Time Factors; D055815:Young Adult
chemical_list: D016207:Cytokines; D006728:Hormones; D015850:Interleukin-6; D004958:Estradiol