title: Dose-dependent effects of genistein and daidzein on protein metabolism in porcine myotube cultures.
abstract: This study was conducted to investigate whether the isoflavones genistein and daidzein, which are components of soy-based diets, and the estrogen 17beta-estradiol affect differentiation and protein metabolism of porcine skeletal muscle cells in vitro. Serum-free porcine myotube cultures expressing the estrogen receptors ERalpha and ERbeta were treated with various concentrations of genistein, daidzein, or 17beta-estradiol for 26 h. The degree of differentiation by creatine phosphokinase activity was not altered by treatment. At 100 micromol/L both genistein and daidzein caused decreases in protein amount due to cell loss. In addition, 100 micromol/L genistein reduced protein synthesis rate of the surviving cells (P < 0.05) measured as [3H]-phenylalanine incorporation. Interestingly, genistein (0.1 micromol/L), daidzein (10, 100 micromol/L), and 17beta-estradiol (0.1, 1 nmol/L) slightly reduced protein degradation (P < 0.05). The results suggest that both genistein and daidzein affect protein metabolism in a dose-dependent manner and that estrogenic actions may play a role in decreasing protein degradation in porcine skeletal muscle.
authors.affiliation: Research Unit Muscle Biology and Growth and Research Unit Genetics and Biometry, Research Institute for the Biology of Farm Animals, Dummerstorf, Germany. rehfeldt@fbn.dummerstorf.de
authors.forename: Charlotte
authors.initials: C
authors.lastname: Rehfeldt
authors.forename: Claudia
authors.initials: C
authors.lastname: Kalbe
authors.forename: Gerd
authors.initials: G
authors.lastname: Nürnberg
authors.forename: Marcus
authors.initials: M
authors.lastname: Mau
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000008:administration & dosage; D019833:Genistein / Q000008:administration & dosage*; D007529:Isoflavones / Q000008:administration & dosage*; D018485:Muscle Fibers, Skeletal / Q000187:drug effects* / Q000378:metabolism; D009124:Muscle Proteins / Q000187:drug effects / Q000378:metabolism*; D013552:Swine
chemical_list: D007529:Isoflavones; D009124:Muscle Proteins; D004958:Estradiol; C004742:daidzein; D019833:Genistein