title: Effects of estrogen replacement and lower androgen status on skeletal muscle collagen and myofibrillar protein synthesis in postmenopausal women.
abstract: Our aim was to determine synthesis rate of myofibrillar and collagen proteins in 20 postmenopausal women, who were either nonusers (Controls) or users of estrogen replacement therapy (ERT) after hysterectomy/oophorectomy. Myofibrillar and muscle collagen protein fractional synthesis rate (FSR) were determined in a nonexercised leg and 24 hours after exercise in the contralateral leg. A significant interaction between treatment and mechanical loading was observed in myofibrillar protein FSR. At rest, myofibrillar protein FSR was found to be lower in ERT users than in Controls. Exercise enhanced myofibrillar protein FSR only in ERT users. Similarly, muscle collagen FSR tended to be lower in ERT users compared with Controls. In ERT participants, the androgen profile was reduced, whereas estradiol and sex hormone-binding globulin were higher. In conclusion, at rest, myofibrillar protein FSR was lower in hysterectomized/oophorectomized women using ERT compared with healthy postmenopausal women. Nevertheless, resistance exercise in combination with ERT seems to have a counteracting effect on myofibrillar FSR in hysterectomized/oophorectomized women.
authors.affiliation: Institute of Sports Medicine, Department of Orthopaedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health Sciences, University of Copenhagen, Denmark. kontakt@mettehansen.nu
authors.forename: Mette
authors.initials: M
authors.lastname: Hansen
authors.forename: Dorthe
authors.initials: D
authors.lastname: Skovgaard
authors.forename: Søren
authors.initials: S
authors.lastname: Reitelseder
authors.forename: Lars
authors.initials: L
authors.lastname: Holm
authors.forename: Henning
authors.initials: H
authors.lastname: Langbjerg
authors.forename: Michael
authors.initials: M
authors.lastname: Kjaer
mesh_terms: D000368:Aged; D000728:Androgens / Q000097:blood*; D016022:Case-Control Studies; D003094:Collagen / Q000096:biosynthesis; D003430:Cross-Sectional Studies; D004958:Estradiol / Q000097:blood; D015914:Estrogen Replacement Therapy; D015444:Exercise / Q000502:physiology; D005260:Female; D006801:Humans; D007044:Hysterectomy; D008875:Middle Aged; D009124:Muscle Proteins / Q000096:biosynthesis; D018482:Muscle, Skeletal / Q000378:metabolism*; D010052:Ovariectomy; D017698:Postmenopause / Q000378:metabolism*; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism
chemical_list: D000728:Androgens; D009124:Muscle Proteins; D012738:Sex Hormone-Binding Globulin; D004958:Estradiol; D003094:Collagen