关键词: 雌性东方田鼠, EP-1, 不育控制

Abstract: Our laboratory study evaluated the effects of a contraceptive compound EP - 1 (levonorgestrel - quinestrol) on fertility in female Microtus fortis calamorum, as measured by changes in hormone levels, reproductive organs, litter size, pregnancy rate and reproduction interval. Some dosages of EP -1 significantly affected uterus coefficient, follicle - stimulating hormone (FSH)levels, ovary coefficient and ovarian tissue morphology, but didn’t obviously affect uterus length or estradiol levels. A dose of 60 mg/kg EP - 1 significantly increased FSH levels and ovary coefficients, however doses of 10 mg/kg or 30 mg/kg EP -1 had no obvious effect on either measurement. Litter size and pregnancy rate were significantly reduced at different dosages of EP -1. The effective sterilization periods following dosage with 10 mg/kg, 30 mg/kg or 60 mg/kg of EP -1 were approximately 16, 38 and 52 days respectively．The time taken for measurements to return to pre-dosing conditions was related to the dose of EP -1. Our results indicate further potential of EP -1 in reducing fertility for the control of Microtus fortis populations in field conditions.

Key words: EP -1 (Levonorgestrel - quinestrol), Female Microtus fortis, Fertility control