Abstract: OBJECTIVE: To investigate the hormone-like activities of Kuntai capsule(KTC) in the uteri of ovariectomized rats and immature rabbits.METHODS: Following bilateral ovariectomy, rats were randomly divided into six groups including sham group, control group, estradiol valerate group, KTC 0.24, 0.6, and 1.5 g/kg groups. The rats were treated with 0.5% CMC-Na, estradiol valerate and KTC(0.24, 0.6, and 1.5 g/kg), respectively for 28 consecutive days. Then the estrous cycle, uterine changes and pathological changes were examined.Serum levels of estradiol(E2), and progesterone(P4)were measured by enzyme-linked immunosorbent assay(ELISA). Protein levels of estradiol receptor(ER), progesterone receptor(PR), vascular endothelial growth factor(VEGF), proliferating cell nuclear antigen(PCNA) and nuclear-associated antigen-67(Ki-67) in uterine tissues were detected by western blot. Immature rabbits were estrogen-primed prior to intragastric administration with KTC for 6 d consecutively. Then, the uteri underwent hematoxylin-eosin staining to observe endometrial transformation.RESULTS: Compared with the control group, 0.6and 1.5 g/kg KTC markedly decreased the uterine organ coefficient and endometrial thickness(P < 0.05). There were no significant variations in the serum level of E2 in the KTC groups compared with the control group. ERβ, but not ERα, was markedly upregulated after KTC administration(P < 0.05). Furthermore, 1.5 g/kg KTC significantly decreased the protein level of PRA(P < 0.05). VEGF was highly expressed after treatment with 0.24 and 0.6 g/kg KTC,and Ki-67 was markedly reduced in ovariectomized rats treated with 1.5 g/kg KTC. No difference was found in the expression of PCNA. KTC 0.24 and0.6 g/kg promoted endometrial transformation in immature rabbit uteri.CONCLUSION: KTC does not demonstrate obvious estrogen-like effect on uteri after ovariectomy, but it does exhibit weak progestogen-like effect, by which mechanism of action is yet to be further investigated.

Key words: Kuntai capsule, Ovariectomiy, Endometritis, Receptors,progesterone, Receptors,estradiol, Vascular endothelial growth factors, Allen-Doisy bioassay, McPhail score