Effect of Chinese herbal medicine for nourishing yin and purging fire on mRNA expressions of gonadotropin-releasing hormone and its receptor in precocious puberty model rats / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To probe the mechanism of Chinese herbal medicine (CHM) for nourishing Yin and purging Fire on the expressions of gonadotropin-release hormone (GnRH) and its mRNA expression in hypothalamus and GnRH receptor mRNA in pituitary in danazol induced precocious puberty model rats.</p><p><b>METHODS</b>Rats were divided into the normal group, the model group, the blank control group and the CHM group. Rats, except that in the normal group, were subcutaneously administered danazol 300 micrograms at 5 days of age individually and CHM was fed to rats in the CHM group from 15 days of age, in the meantime, normal saline was fed to rats in the blank control group. Expression of GnRH in hypothalamus was observed by immunohistochemical method and expressions of GnRH mRNA in hypothalamus and GnRH receptor mRNA in pituitary were determined by RT-PCR.</p><p><b>RESULTS</b>Compared with rats in the normal groups, the vaginal opening and the onset of first estrus were ahead of time, the number of GnRH immunoreactive positive cells decreased and the expressions of GnRH mRNA in hypothalamus and GnRH receptor mRNA in pituitary up-regulated in the model rats and blank control rats. Compared with the model and the blank control groups, in CHM group, all the above-mentioned abnormally changed parameters improved significantly after treatment.</p><p><b>CONCLUSION</b>CHM for nourishing Yin and purging Fire may inhibit the abnormal hyperfunction of hypothalamus-pituitary-ovary axis in precocious puberty rat induced by danazol via reducing the synthesis and release of GnRH, and lowering the responsibility of pituitary cells to GnRH. This may be the primary mechanism of CHM in effectively treating the true precocious puberty.</p>

Expressions of GnRH and GnRH receptor mRNA in female rats with danazol-induced precocious puberty / 中华内分泌代谢杂志

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 ?g 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