左旋18甲基炔诺酮增加大鼠血清瘦素及下丘脑瘦素受体表达

口服避孕药因具有高效、安全的特点而在临床广泛应用,但随之带来的副作用日益引起学者的重视,如体重增加、月经异常等,关于其引起体重增加的有关研究少见报道。瘦素(leptin)是近年来发现的衡量体脂水平的重要指标,又是连接能量和生殖的桥梁。因此,本研究选用左旋18-甲基炔诺酮(     

左旋18-甲基炔诺酮对大鼠雌激素水平及下丘脑雌激素受体阳性细胞的影响

目的:观察左旋18-甲基炔诺酮(LNG)对大鼠雌激素(E)水平及下丘脑内雌激素受体(ER)阳性细胞的影响。方法:正常雌性SD大鼠分为给药对照组、给药组、停药对照组、停药组,应用免疫组织化学方法显示下丘脑ER阳性细胞并检测血清E浓度。结果:给药组较给药对照组E浓度下降,弓状核(Arc)、下丘脑腹内侧核(VMH)内ER阳性细胞的数量减少、光密度下降。停药后基本恢复正常。结论:长期LNG作用导致给药大鼠血清E水平下降;长期LNG作用引起大鼠下丘脑ER数量减少、活性减低,推测ER可能参与影响促性腺激素释放激素的分泌;停药后ER的形态学变化恢复正常,所以LNG的作用基本上是可逆的。     

LNG对大鼠下丘脑内NPY神经元的影响

左旋18-甲基炔诺酮(Levonorgestrel LNG)是第二代全合成孕激素类口服避孕药,反馈性调节下丘脑—垂体轴是其作用机制之一。在下丘脑-垂体-性腺轴中,多种神经递质参与了下丘脑促性腺激素释放激素(gonadotrop in-releasing hor-mone,GnRH)的分泌调节,其中神经多肽Y(neuropeptide Y     

脑室注射L-谷氨酸对成年大鼠下丘脑GnRH含量的影响

目的 :观察脑室注射L -谷氨酸 (L -Glu)对成年雄性Wistar大鼠下丘脑促性腺激素释放激素(GnRH)含量的影响。方法 :摘取下丘脑组织 ,匀浆化 ,用RIA法检测匀浆上清液中GnRH的含量。结果 :脑室分别注射 0 0 1176、0 1176、1 176 0 μg/ 2 0 μl-1 -1L -Glu后 40分钟 ,下丘脑GnRH含量依次为 1 5 9± 0 41、0 88± 0 34、0 70± 0 42ng/ 10mg湿重 ,均显著低于盐水对照组 (P <0 .0 1) ;脑室注射 0 1176 μg/ 2 0 μl-1·-1L -Glu后 2 0、40、12 0分钟 ,下丘脑GnRH含量依次为 0 99± 0 37、0 88± 0 34、1 2 6± 0 39ng/ 10mg湿重 ,亦均显著低于盐水对照组 (P <0 .0 1)。脑室注射L -Glu对下丘脑GnRH含量的降低作用呈现剂量与时间依从关系。而脑室注射3H -Glu 2 μCi/ 2 0 μl-1·-1后 40分钟发现 ,大脑、小脑、垂体、下丘脑内侧基底部 (MBH)和视前区 (POA) 5个不同部位脑组织中以MBH对3H -Glu的摄取量最大 (10 6 9 82± 490 33cpm/ 10mg湿重 )。结论 :L -Glu可能参与了大鼠下丘脑GnRH神经元功能活动的调节。     

哺乳期雌性大鼠下丘脑内促性腺激素释放激素神经元的免疫组织化学研究

采用免疫组织化学方法研究了产后授乳和中断授乳的雌性大鼠下丘脑内促性腺激素释放激素(GnRH)阳性神经元和神经纤维的密度和染色反应的变化.在哺乳的第3天,将半数母鼠的仔鼠去除,中断授乳后1～4天下丘脑内侧隔核、视前内侧区和Broca斜角带内的GnRH阳性神经元胞体的反应强度明显高于继续授乳组.在正中隆起和终板血管器的GnRH阳性纤维和终末的密度和染色强度也比授乳组明显增加.结果表明:中断授乳的母鼠下丘脑内GnRH分泌神经元激素的合成和释放功能均明施增强,而哺乳对下丘脑内GnRH神经元的合成和释放激素的功能有显著的抑制作用.     

GnRH拮抗剂在体外受精-胚胎移植中的应用

目的探讨促性腺激素释放激素（GnRH）拮抗剂方案在体外受精-胚胎移植（IVF—ET）促超排卵中的应用效果。方法回顾性比较分析本中心2006年8月～2007年8月接受ⅣF—ET助孕治疗的患者中采用GnRH拮抗剂方案的54例患者和采用GnRH激动剂长方案的135例患者，观察其临床效果。结果两组Gn用量、HCG日内膜厚度、受精率、卵裂率之间比较无显著性差异；两组患者Gn使用天数、HCG日E2值、获卵数、冷冻率、种植率、妊娠率、OHSS发生率之间比较有显著性差异。结论GnRH拮抗剂联合促性腺激素促超排卵方案缩短用药时间，减少费用，并可显著降低OHSS的发生率，但冷冻率、妊娠率较GnRH激动剂长方案偏低。     

GnRH拮抗剂与GnRH激动剂短方案IVF-ET结局的比较

目的比较GnRH antagonist与GnR Hagonist短方案的IVF-ET结局。方法2006年8月至2007年8月GnR Hantagonist治疗组54人和GnR Hagonist短方案对照组132人,记录促性腺激素的用量及其用药天数、hCG日子宫内膜厚度和激素水平、获卵数、受精率、卵裂率、优胚率、妊娠率和OHSS发生率等指标。结果两组促性腺激素的用量及其用药天数、获卵数、受精率、卵裂率、着床率和妊娠率相比较均无显著差异（P〉0.05）。GnR Hantagonist组在hCG日激素水平低,与对照组比较其差异有统计学意义。结论行GnR Hantagonist方案IVF-ET助孕治疗与传统的GnR Hagonist短方案比较,其hCG日雌激素水平下降可能是OHSS发生率显著下降的主要因素;但卵泡的发育、卵母细胞的受精率、卵裂率及妊娠率和着床率均不受影响。GnR Hantagonist的使用为IVF-ET助孕药物提供了一种新的选择。     

GnRH类似物对大鼠回肠组织胰高血糖素释放的影响

目的 :研究促性腺激素释放激素 (GnRH)类似物 (阿拉瑞林 )对大鼠回肠L细胞释放胰高血糖素的影响。方法 :应用放射免疫分析法对体内和体外大鼠回肠进行观察。结果 :大鼠回肠灌注GnRH类似物后 ,血中及肠液中胰高血糖素的含量较对照组明显升高 ;体外孵育大鼠回肠组织后 ,在一定浓度范围内 ,孵育液中胰高血糖素含量随GnRH类似物浓度升高而升高 ;当浓度高于一定范围时 ,则随浓度升高而降低。GnRH类似物浓度为 1 .0× 1 0 - 4mol/L时孵育液中胰高血糖素含量是升高的。结论 :GnRH可能对大鼠回肠L细胞分泌胰高血糖素呈现双向调节作用。但是GnRH类似物为 1 .0× 1 0 - 4mol/L ,不论是体内还是体外 ,都可能对肠道分泌胰高血糖素表现促进作用     

GnRH 相关肽在啮齿类前脑及下丘脑分布的免疫组织化学研究

人和大鼠的促性腺激素释放激素原(ProGnRH),由 GnRH 和 GnRH 相关肽(GAP)组成。本文应用3种分别抗人和大鼠 GAP N-末端、中段和 C-末端的抗血清和 ABC 免疫酶法,对大鼠、小鼠和豚鼠脑 GAP 神经元进行了观察。3种动物的 GAP 神经元分布相似,GAP 神经元胞体主要存在于隔-视前区,以终板血管器附近的斜角带最为集中。视上核附近亦有较多的 GAP神经元。GAP 纤维广泛存在于前脑和下丘脑,终止于终板血管器和正中隆起。3种 GAP 抗血清中,以抗 N-末端者染出的免疫反应阳性成分多,染色深。GAP 神经元与相邻切片上所染的 GnRH神经元的胞体、纤维和终末的形态和分布相同。本文的观察和其他有关的研究提示,哺乳类具有相同的 ProGnRH,其加工产物 GAP(或其裂解片段)与 GnRH 共同分泌到垂体门脉,调节垂体前叶的激素分泌。     

卵泡刺激素在大鼠胰腺中的定位及其与促性腺激素释放激素受体共存关系

目的：研究卵泡刺激素在大鼠胰腺中的分布及其与促性腺激素释放激素受体的共存关系。方法：采用免疫组织化学法和邻片双标记方法。结果：大鼠胰腺外分泌部腺泡内的部分腺细胞和胰岛中的部分内分泌细胞呈现FSH免疫阳性反应,阳性产物分布于胞质,胞核阴性。卵泡刺激素与促性腺激素释放激素受体在大鼠胰岛细胞中有重叠分布。结论：大鼠胰腺外分泌部的腺泡细胞和胰岛的细胞能表达卵泡刺激素。卵泡刺激素和促性腺激素释放激素受体共存于大鼠胰岛细胞中。表达卵泡刺激素的胰岛细胞可能受促性腺激素释放激素调节。     

Effect of gonadotropin-releasing hormone analogue on thermal nociception in mice

Intraperitoneal treatment with an analogue of gonadotropin-releasing hormone in doses of 0.004–450 μg/kg produced an analgesic effect on male mice in the hot plate test. Castration significantly elevated the nociceptive thresholds. In castrated mice the effects of the test peptide were less pronounced and had an algesic nature. Our results indicate that these effects depend on functional activity of the hypothalamic-pituitary-gonadal axis. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 141, No. 2, pp. 153–156, February, 2006     

Evidence that prostate gonadotropin-releasing hormone receptors mediate an anti-tumourigenic response to analogue therapy in hormone refractory prostate cancer

Gonadotropin-releasing hormone analogue (GnRHa) therapy is an established method of androgen withdrawal in the treatment of prostate cancer. The present study investigated if the expression of prostate GnRH receptors (GnRHRs) might influence the response to GnRHa. GnRHR protein expression was first studied in a panel of prostate cancer cell lines. In androgen-dependent cells, GnRHR expression was unchanged following acute or chronic androgen withdrawal. In these cells, GnRHa significantly inhibited androgen-induced cell proliferation (p = 0.01). In contrast, GnRHa was unable to further suppress basal levels of cell proliferation induced by androgen withdrawal. In androgen-independent prostate cancer cells, variable levels of GnRHR expression were observed. In these cells, GnRHa treatment blocked cell proliferation (p = 0.001) and invasion (up to 70%) induced by fibroblast growth factor stimulation. Crucially, this effect was only evident in cells that expressed high levels of the GnRHR. GnRHa treatment also significantly inhibited the ability of these cells to recover from a cytotoxic insult (50% inhibition). The clinical significance of prostate GnRHR was tested by immunohistochemistry in a preliminary cohort of patients treated with GnRHa or surgical castration. There was no association between GnRHR expression and pathological grade, clinical stage, time to PSA nadir (p = 0.82) (n = 35) or progression to hormone refractory disease (p = 0.22) (n = 21), irrespective of the treatment method. GnRHa therapy in the presence of high GnRHR expression however, was found to be associated with longer disease-specific survival (mean survival 85 months, p = 0.002). In contrast, high GnRHR expression was not associated with survival among surgically castrated patients (mean survival 50 months, p = 0.7). Taken together, these data support the notion of a functional interaction between GnRHa and the GnRHR, which results in an anti-tumourigenic effect on prostate cancer cells. Findings from this report have direct implications for the use of GnRHR as a novel therapeutic target in hormone refractory prostate cancer.     

Sleep deprivation increases somatostatin and growth hormone-releasing hormone messenger RNA in the rat hypothalamus

We studied the effect of sleep deprivation (SD) on the amount of somatostatin (SRIF) and growth hormone-releasing hormone (GHRH) mRNA in rat hypothalamic nuclei. According to earlier studies SRIF possibly facilitates REM sleep and GHRH slow-wave sleep. Adult male rats were sleep deprived by the gentle handling method either for 6 h during the first half of the light phase or for 12 h during the dark phase. Undisturbed rats sacrificed at the same time as the SD rats served as controls. After oligonucleotide in situ hybridization the amount of SRIF and GHRH mRNA was measured in brain sections by image analysis and cell count. SD increased the amount of SRIF mRNA in the arcuate nucleus (ARC). In the periventricular nucleus (PE) there was no effect. The amount of GHRH mRNA increased in the paraventricular nucleus (PA) in the 6 h SD group but no effect was detected in ARC. In the periventromedial hypothalamic area (pVMH) the amount of GHRH mRNA was higher in the control rats sacrificed in the morning (09.00 hours) than in the afternoon (15.00 hours), and SD had no effect. We conclude that SRIF cells in ARC and GHRH cells in PA are modulated by sleep loss, which is in accordance with the possible sleep regulatory function of these neuropeptides.     

Immunocytochemical localization of luteinizing hormone-releasing hormone in neurons in the medial basal hypothalamus of the female rat

Summary Luteinizing hormone-releasing hormone (LHRH)-neurons were localized with a LHRH antiserum (WP-1) in the medial basal hypothalamus (MBH) of the female rat using the sagittal hypothalamic slice preparation in combination with the peroxidase-antiperoxidase immunocytochemical technique of Sternberger (1979). Numerous darklystained perikarya were visualized in the cell-poor zone, lateral arcuate nucleus and the median eminence. The processes of these neurons contributed to the intensely-stained fiber bundle above the tubero-infundibular sulcus. The fibers in this tract run in a rostrocaudal plane in the lateral external zone of the median eminence. Also, numerous fibers course into the internal zone of the median eminence, perpendicular to the rostrocaudal plane. Several LHRH-immunoreactive perikarya also were identified in the periventricular area caudal to the optic chiasm (retrochiasmatic area). The LHRH neurons were small (10 m) bipolar neurons with fibers (dendrites) exiting from either pole which showed very little branching. It appears that the sagittal slice in combination with the appropriate fixation procedure and LHRH antiserum enabled us to demonstrate the presence of LHRH-immunoreactive perikarya in the MBH of the female rat.Supported by Health Research Services Foundation Grant W-22 and NIH Grant NS16419     

Immunocytochemical colocalization of GABA-B receptor subunits in gonadotropin-releasing hormone neurons of the sheep

GABA has been shown to play an important role in the control of gonadotropin-releasing hormone (GnRH) and luteinizing hormone secretion in many mammals. In sheep, seasonal differences in the ability of GABA-B receptor antagonists to alter pulsatile luteinizing hormone secretion have led to the hypothesis that this receptor subtype mediates the increased inhibitory effects of estradiol on GnRH and luteinizing hormone pulse frequency seen during the non-breeding season (anestrus). The aim of the present study was to use multiple-label immunocytochemistry to determine if ovine GnRH neurons contain the GABA-B receptor subunits R1 and/or R2, and to determine whether there are seasonal differences in the colocalization of these subunits in GnRH neurons. A majority of GnRH cells in the preoptic area, anterior hypothalamic area, and medial basal hypothalamus of both breeding season and anestrous ewes contained either GABA-B R1 or R2 subunits; a subset of GnRH neurons in breeding season (42%) and anestrous ewes (60%) contained both subunits. In contrast to colocalization within cell bodies, GnRH fibers in the median eminence did not colocalize GABA-B receptor subunits. Although the percentage of GnRH neurons expressing GABA-B receptor subunits tended to be higher in anestrus than in the breeding season, there were no significant seasonal differences in R1 and R2 subunit colocalization in GnRH cell bodies. Thus, while GABA may act directly on GnRH cell bodies via GABA-B receptors in the sheep, any role that GABA-B receptors may play in seasonal reproductive changes is likely mediated by other neurons afferent to GnRH cells.     

精氨酸加压素阳性神经元在大鼠下丘脑的定位

目的:观察大鼠精氨酸加压素(AVP)及其mRNA阳性神经元在下丘脑的分布和形态特征。方法:以尼氏染色作参照,运用免疫组化和原位杂交观察AVP及其mRNA在下丘脑的表达。结果:下丘脑AVP及其mRNA阳性的神经元由吻侧到尾侧依次出现于视上核,视上核和视交叉上核,视上核、视交叉上核和室旁核,视上核和室旁核及视上核、下丘脑前核和室旁核。AVP及其mRNA阳性神经元仅占据视上核背内侧;在第三脑室室管膜膜内或膜下可见AVP阳性神经元的胞体或突起;在不同核团内AVP阳性神经元的形态存在差异。结论:AVP及其mRNA阳性神经元在下丘脑不同核团内具有特异性分布;AVP阳性触液神经元可能是调节脑脊液和脑组织之间AVP含量的桥梁。     

去卵巢后雌性大鼠下丘脑视前区NOS阳性神经元形态学和突触素表达的变化

目的：为解释围绝经期的精神、神经症状提供实验依据。方法：采用免疫细胞化学方法显示去卵巢雌性大鼠下丘脑视前内侧区(MPA)和视前外侧区(LPA)内NOS阳性神经元,形态学改变以及突触素表达。结果：(1)去卵巢组和对照组大鼠的视前内、外区内可见大量NOS阳性神经元;(2)去卵巢动物的下丘脑内NOS阳性神经元突起长度比对照组的明显变短,分支明显变少;(3)去卵巢组动物下丘脑内突触素表达比对照组的明显减少。结论：大鼠去卵巢后,由于雌激素分泌减少,导致了NOS阳性神经元的突起减少和突触减少,结果NO介导的神经元信号传导失常,这些变化可能是引发围绝经期的精神、神经症状的原因之一。