电场刺激对离体去卵巢大鼠垂体前叶FSH分泌的兴奋作用

Excitatory Effects of Electrical Field Stimulation on FSH Secretion in the Anterior Pituitary of Ovariectomized Rats in vitro

目的:探讨垂体前叶神经纤维对FSH分泌的神经调节。方法:经阴道涂片筛选出动情间期大鼠40只,切除双侧卵巢术后7d处死,取垂体前叶,用Krebs液或含河豚毒素(tetrodotoxin,TTX)的Krebs液离体灌流,同时施加频率为10Hz或2Hz、时间为10min或2min的电场刺激。从刺激开始前10min起,每10min收集灌流液1次,连续收集130min。放免法检测各时段收集液中FSH浓度。结果:在Krebs液灌流条件下,10Hz、连续10min的电场刺激后10min内,垂体灌流液中的FSH浓度(14.4±0.8mIU/ml)较基础水平(8.4±1.4mIU/ml)有显著增高(P<0.05)。而改用含TTX的Krebs液灌流后,同条件的电场刺激后10min内FSH浓度为8.2±0.6mIU/ml,提示其分泌被显著抑制(P<0.05)。其余各参数的电场刺激对FSH分泌均无明显影响。结论:电场刺激对离体去卵巢大鼠垂体前叶FSH分泌有兴奋作用,提示垂体前叶内的神经纤维可能对FSH的分泌存在直接的调节作用。

Objective： To investigate verify the neural regulation of nerve fibers in anterior pituitary on the secretion of follicle-stimulating hormone （FSH）. Methods： Forty diestrus rats determined by vaginal smear examination were ovariectomized and sacrificed 7 d after surgery. The pituitary was removed and superfused with Krebs solution （Krebs-Ringer-bicabonate-BSA buffer, KRBGA） with or without tetrodotoxin （TTX）. EFS was performed at 10 Hz or 2 Hz for 10 min or 2 min, respectively, and the perfusate was continuously collected every 10 min for 130 min and measured for FSH by radioimmunoassay, Results： With the anterior pituitary superfused with KRBGA, EFS at 10 Hz for 10 min significantly increased FSH secretion （14.4 ± 0.8 mIU/ml） 10 min after ending of stimulation, incomparison with the basal secretion level （8.4 ± 1.4 mIU/ml） （P〈0.05）. However, the excitatory effect of EFS on FSH secretion was abolished if the TTX was added into the perfusate, FSH concentrations decreased to 8.2 ± 0.6 mIU/ml in 10 min after ending of stimulation. Other variables of EFS parameters had no effect on FSH secretion. Conclusion： EFS has an excitatory effect on FSH secretion in the anterior pituitary of ovarectomized rat in vitro. The result indicates that nerve fibers in the anterior pituitary might play a direct modulatory role for FSH secretion.