Abstract:

【Objective】 To determine whether flaxseed lignans could affect the growth of skeletal muscle in male animals and its possible mechanisms. 【Method】 The effect of the flaxseed lignans on skeletal muscle in male rats were determined in vivo. Daidzein (5 mg?kg-1) and flaxseed lignans (50 mg?kg-1) were added into the basal diets, respectively, and the concentrations of the serum lignans and daidzein were measured by HPLC, serum growth hormone and testosterone (T) levels were analyzed by RIA, and the expression of estrogen receptor β (ERβ) in the soleus muscle and hypothalamus were determined by RT-PCR. 【Result】 Flaxseed lignans and daidzein significantly improved the feed efficiency and increased the total weight gain of the femoral muscle in male rats. The rate of RNA to DNA in muscles and serum T levels were remarkably increased, while the urea nitrogen concentrations were significantly decreased by daidzein and flaxseed lignan and/or its metabolites. Meanwhile the expression of estrogen receptorβ (ERβ) in soleus muscle and hypothalamus were both upgraded by the two phytoestrogens. 【Conclusion】 Flaxseed lignan promoted the growth of male rats, and it may regulate serum T levels through binding to ER β in hypothalamus. In turn, it depressed the catabolism of protein and promoted the hypertrophy of skeletal muscle cells.

Key words: phytoestrogens, flaxseed lignans, daidzein, mammalian lignans, skeletal muscle growth