Tu-chung (Eucommia ulmoides) Leaf Extract Does Not Enhance Whole-Body Protein Synthesis in the Chicken Embryo Cultured In Vitro

Tu-chung (Eucommia ulmoides, Oliver) is a Chinese medical herb which has been used for the sake of health for a few thousand years. In animal experiments, it was reported that Tu-chung leaf extract increased relative weight of both liver and small intestine in the rat (MA et al., 1987), and body weight of mice (YoxoGosHi et al., 1991). In laying hens, SHIOYA et al., (1990) reported that administration of Tu-chung leaf improved egg production rates in the late production phase. These findings lead one to speculate that Tu-chung leaf extract contains physiologically active substances that may regulate protein metabolism of animals. One of the important processes in protein metabolism which might be stimulated by Tu-chung leaf extract would be protein synthesis, because Y0K0G0SHI et al. (1991) found an increase in muscle protein synthesis in senescent mice. The present study was conducted, therefore, to investigate whether supplementing with Tu-chung leaf extract would enhance whole-body protein synthesis in chicken embryos by using a whole-embryo culture system which was found to be useful for screening physiologically active substances in chickens (MURAMATSU et al., 1993b,c; KITA et al., 1993).