Objective To investigate the effects of nordihydroguaiaretic acid (NDGA) on the ovary in rats. Methods Forty female SD
rats in normal estrous cycles were randomly divided into PBS group and NDGA group, subcutaneously injected of PBS solution and 3% NDGA at the dose of 30 mg/kg respectively every other day for 16 d. The serum concentrations of follicle stimulating hormone (FSH), luteinizing hormone (LH), estrogen (E 2) and progesterone (P) were measured by chemiluminoimmunoassay before and after administration and the mating was confirmed by the occurrence of vaginal plugs and the morphological changes of uterus and ovaries were examined by immunohistochemistry after administration. Results None of the NDGA-treated rats were able to successfully mate as the absence of vaginal plugs were detected. The endometrium could maturate in all of the NDGA-treated rats, but there had a decrease not only in the number of
endometrial glands, but also the proliferation rate of the glandular epithelial cells, the endometrial stroma cells, the vessels and the microvacular density (P<0.01). The number and area ratio of both mature corpus luteums and follicles were lower than those of control group, but the number of the atretic follicles had increased (P<0.01). The serum concentration of E 2 had decreased significantly (P<0.01) and P had increased in estrus and decreased in metaestrus and FSH had increased in estrus and metaestrus (P<0.05), but that of LH had no statistical difference. Conclusion The long-term treatment of NDGA may make the ovarian functional disturbance in the rats.