Effect of mifepristone on morphology of adenohypophysial gonadotropic cells in rat with endometriosis

Objective: To observe the effect of mifepristone on the appearance and structure of adenohypophysial follicle-stimulating hormone-secreting cells (FSH cell) and luteinizing hormone-secreting cells (LH cell) in rat with endometriosis.Methods: Wistar female rats with regular estrus cycle and 80~90 days of age were used to establish the models of endometriosis. The different dosages of mifepristone (10 mg·kg~(-1)·d~(-1), 25 mg·kg~(-1)·d~(-1), 50 mg. kg~(-1)·d~(-1)) were given by pouring into stomach (ig.) of rats in the experiment group. The tap water was given in control group. The rats in ovariectomized group only had their bilateral ovaries (removed) without administration of mifepristone. The density and morphology of FSH cell and LH cell in (hypophysis) were studied by immunohistochemistry 4 and 8 weeks later.Results: As compared with the control group, the density of positively stained cells in the hypophysis of experiment group was lower with longer administration of mifepristone (P0.05) and the mean diameter of positive cells reduced with increase in dosage and administration days (P0.05). The density and mean diameter of positive cells in the hypophysis were significantly increased with extension of the time in ovariectomized group.Conclusion: It is possible that mifepristone influences the secretion of ovarian hormones by down-regulating the secretory function of gonadotrophic cells in adenohypophysis of rats with endometriosis and (results) in atrophy of ectopic endometrium. This finding is probably one of the mechanisms of mifepristone for endometriosis.