Intramuscular sex steroid hormones are associated with skeletal muscle strength and power in women with different hormonal status
International audience; Estrogen (E2)-responsive peripheral tissues, such as skeletal muscle, may suffer from hormone deficiency after menopause potentially contributing to the aging of muscle. However, recently E2 was shown to be synthesized by muscle and its systemic and intramuscular hormone levels are unequal. The objective of the study was to examine the association between intramuscular steroid hormones and muscle characteristics in premenopausal women (n = 8) and in postmenopausal monozygotic twin sister pairs (n = 16 co-twins from eight pairs) discordant for the use of E2-based hormone replacement. Isometric skeletal muscle strength was assessed by measuring knee extension strength.…
Cannabinoid receptor 1 and acute resistance exercise – In vivo and in vitro studies in human skeletal muscle
Abstract Aim This study aimed to determine whether Cannabinoid receptor 1 (CB1) is involved in mammalian target of rapamycin (mTOR) signaling and skeletal muscle protein synthesis. Methods This study used human vastus lateralis skeletal muscle biopsies obtained before and after a resistance exercise (RE) bout in young men (n = 18). The signaling mechanisms were studied in vitro in human myotubes. Protein expression was determined by Western blot and confocal microscopy, and gene expression by quantitative PCR. Protein synthesis was measured in vitro using puromycin-based SuNSET technique. Results In human skeletal muscle, an anabolic stimulus in the form of RE down-regulated CB1 expression.…