Abstract: OBJECTIVE: To evaluate the estrogenic efficacy of Renshen(Radix Ginseng)(GS) on reproductive target tissues in immature mice.METHODS: One hundred and ten female immature Kunming(KM) mice, 21-day-old, were randomly assigned to eleven groups, 10 for each; one served as control group treated with 0.154 mg/kg estradiol valerate(EV,n = 10), the rest were treated respectively with GS intragastrically at a daily dose of 0.5,1.0, 1.5, 3.0, 6.0, 12.0, 18.0, 24.0 and 30.0 g/kg(n =10 in per group) for 7 days. The estrous cycle, uterine weight, hormone levels in circulation and histomorphology changes of uterus and vagina were scrupulously examined. The estrogen receptor(ER)α and ERβ expressions in the uterus and vagina were detected by immunohistochemistry and western blotting.RESULTS: Treatment with GS at the dose of 12.0,18.0 and 24.0 g/kg resulted significant estrogenic activity in the mice, as indicated by advanced and prolonged estrous stage and increased uterine weight(all P < 0.05). GS treatment substantially promoted development of reproductive tissue by thickening the uterine endometrium and increasing vaginal epithelial layers. In addition, treatment with GS induced significant up-regulation of ERαand ERβ expressions in reproductive tissues, and ERα up-regulation was stronger than that of ERβ.GS could raise levels of circulating estrogen, simultaneously decrease levels of luteinizing hormone and follicle-stimulating hormone(all P < 0.001)compared with the control group.CONCLUSION: Our findings suggest that GS had estrogenic effect on reproductive tissues in immature mice by stimulating biosynthesis of estrogen in circulation and up-regulating ERs.

Key words: Panax, Uterus, Vagina, Receptors,estro-gen, Follicle stimulating hormone, Luteinizing hor-mone