达那唑诱导的雌性性早熟大鼠GnRH及其受体mRNA的表达

Expressions of GnRH and GnRH receptor mRNA in female rats with danazol-induced precocious puberty

目的 观察达那唑对雌性大鼠下丘脑 垂体 靶腺轴及下丘脑GnRHmRNA和垂体GnRH受体mRNA表达的影响。方法 5天龄雌性大鼠皮下一次注射 3 0 0 μg达那唑以诱导真性性早熟。从 2 5日龄起观察和记录阴门开启鼠龄和从阴门开启日起进行阴道涂片以确定第一个动情周期。检查阴道涂片和体重及垂体、肾上腺、子宫、卵巢器官重量 ,观察雌激素依赖的阴道脱落细胞的周期性变化和主要器官的发育情况。RT PCR法观察雌性大鼠下丘脑GnRHmRNA和垂体GnRH受体mRNA的表达。结果 5日龄雌性大鼠给予皮下注射达那唑 ,可诱导大鼠阴门提前开启和建立性周期的时间提前 ,子宫和卵巢的重量明显增加 ,下丘脑GnRHmRNA和垂体GnRH受体mRNA的表达升高。结论 达那唑对雌性大鼠下丘脑 垂体 卵巢轴有多层次的作用 ,可诱导雌性大鼠下丘脑 垂体

Objective To ob se rve the effects of danazol on hypothalamus-pituitary-gonad axises and expressi ons of hypothalamic GnRH and pituitary GnRH receptor mRNA in female rats. Methods Female rats at 5 days of age were given a sin gle subcutaneous injection of 300 μg danazol to induce true precocious puberty. Animals were divided into 3 groups: normal control, model group and vehicle gro up. The day of vaginal opening from 25 days of age was monitored, and the establ ishment of first estrus cycle from the day of vaginal opening was investigated b y examination of vaginal smears. The weights of body, pituitary, adrenal, uterus and ovary were measured to identify the developmental status of main organs. Th e expressions of hypothalamic GnRH and pituitary GnRH receptor mRNA were assayed by semi-quantitative RT-PCR. Results Female rats treated with danazol significantly (P<0.01, respective ly) advanced the day of vaginal opening 〔(34.0±1.0)days vs (26.0±2.2)days〕 and first estrus 〔(41.3±2.4)days vs (32 .4±0.8)days〕. The ovary and uterus organ coefficients were higher in model gro up than those in normal control. GnRH and GnRH receptor mRNA were significantly increased in the female precocious puberty rats induced by danazol. Conclusion Danazol advances the onset of hypothalamus-pitu itary-ovary axis function, this precocious rat could represent a model for stud ying the mechanism of puberty.