Effects of neural peptides on the release of pituitary hormones and their fluctuations within the brain in domestic animals.

1.从当地屠宰场采集奶牛下丘脑和脑垂体组织进行灌流，研究神经肽对奶牛脑垂体生长激素(GH)、黄体生成素(LH)和催乳素(PRL)释放的影响。成熟的雌性山羊是一种反刍动物，在一项灌流研究中也使用了类似的方法。实验所用神经肽为血管活性肠肽(VIP)、P物质(SP)、生长激素释放因子(GRF)、缩胆囊素(CCK)、组氨酸异亮氨酸(PHI)、血管紧张素Ⅱ(A II)。除了这些多肽外，还使用了脑垂体后叶组织提取物进行灌流研究。用放射免疫法测定灌流液中GH、LH、PRL的含量。(1)当稀释倍数从10^~(-6)~10^~(-8)~10^~(-8)M时，VIP以剂量依赖的方式释放GH，直接作用于垂体。在停止VIP灌流后不久，GH水平的升高就下降了。…更多的GRF以剂量依赖的方式从垂体释放GH，从10^&lt；-6&gt；M到10@&gt；d1-11@&gt；D1M。用10^~(-6)M~10^~(-8)M VIP稀释到10^~(-8)M VIP时，GRF在停止GRF灌流至少80分钟后仍能持续释放GH；(2)在类似的灌流体系中，山羊脑垂体组织以剂量依赖的方式释放GH，以响应10^~(-6)M~(-9)M VIP的灌流。(3)10^&lt；-8&gt；M CCK抑制去势黄牛脑垂体组织中黄体生成素的释放，而10^&lt；-6&gt；M CCK则促进黄体生成素的释放。(4)催乳素释放因子(PRF)、VIP、SP、CCK、PHI和AⅡ在10~(-7)M剂量水平下不能从奶牛脑垂体释放PRL，但10~(-7)M SP能抑制PRL的释放。当1/2~1/8等量的垂体后叶提取物在下丘脑-垂体组织上灌流时，奶牛的垂体后叶提取物可显著释放催乳素。提示PRF可能存在于奶牛的脑垂体后叶。用推拉导管技术，在猪下丘脑和山羊下丘脑中发现了LHRH的脉动性释放。较少

1. The hypothalamus and pituitary tissues of cows were collected from a local slaughter house and superfused them in order to investigate the effects of neural peptides on the release of pituitary growth hormone (GH), luteinizing hormone (LH) and prolactin (PRL). Mature female goats, a ruminant animal, were also used similarly in a superfusion study. The neural peptides used for the experiments were vasoactive intestinal peptide (VIP), Substance p (SP), growth hormone releasing factor (GRF), cholecystokinin (CCK), peptide histidine isoleusine (PHI), angiotensin II (A II). In addition to these peptides, a posterior pituitary tissue extract was used for the superfusion study. GH, LH and PRL contained in the perifusion efflux were measured by radioimmunoassays. (1) VIP released GH in a dose dependent manner acting directly to the pituitary when dilution rates from 10^<-6>M to 10^<-8>M VIP were used for the perifusion. This rise in GH level declined soon after cessation of VIP perifusion. … More GRF released GH from the pituitary in a dose dependent manner from 10^<-6>M to 10@>D1-11@>D1M GRF. GRF released GH continuously even after the cessation of GRF perifusion for at least 80 min when dilution rates from 10^<-6>M to 10^<-8>M VIP were used for perifusion (2) In the similar perifusion system goat pituitary tissues released GH in a dose dependent manner in response to perifusion of 10^<-6>M to 10^<-9>M VIP. (3) 10^<-8>M CCK inhibited release of LH from perifused pituitary tissues from castrated oxen, while 10^<-6>M CCK stimulated release of LH. (4) Possible candidates for prolactin releasing factor(PRF), VIP, SP, CCK, PHI and A II failed to release PRL from the perifused pituitaries of cows at a dose level of 10^<-7>M, but 10^<-7>M SP inhibited PRL release. Posterior pituitary extracts from cows released pituitary PRL remarkably when 1/2 to 1/8 equivalent posterior pituitary extracts were perifused on the hypothalamus-pituitary tissues. It is suggested that PRF could be contained in the posterior pituitary in cows. Using a push-pull canula technique, a pulsatile release of LHRH was found in the pig hypothalamus and the goat hypothalamus. Less