FOLLICULO-STELLATE CELLS OFTHE RAT ANTERIOR PITUITARY RESPONDED TO ANGIOTENSIN Ⅱ BY INCREASING INTRACELLULAR CONCENTRATION

Objective The main purpose of this study was to investigate whether the folliculo-stellate cells (FSC) respond to angiotensin(Ang) Ⅱ by increasing intracellular free concentration ([]i) ,and where the o-rigin of mobilization is if that has occurred. Methods Pituitary cells in primary culture were prepared from male Wister rats(250g) by a conventional method and cultured in MEM supplemented with 4％ normal rat serum. Af-ter 2 days in culutre,cells were loaded with 1 μmol/L fura-PE3/AM for 1 h and subjected to a ment with Quanti Cell 700 system. Excitation wavelengths of 340 and 380 nm were selected by means of a computer-controlled filterwheel. Results The of FSC in the rat anterior pituitary was elevated by Ang Ⅱ. The eleva-tion of of FSC induced by 0. 1,1.0,10 and 100 nmol/L Ang Ⅱ was (56.33±6.18), (117.07± 36.07), (175.59 ± 40.01 ) and (216.02 ±11.52) nmol/L, respectively. The increase of of FSC induced by 100nmol/L Ang Ⅱ was not influenced by the medium without (0Ca),but significantly suppressed by thapsigargin (TG),an inhibitor of ATPase. The rate of responsive FSC to Ang Ⅱ (100 nmol/L) was 61.84％ which was obviously higher than that of pituitary endocrine cells (43.49％). Conclusion The present experiment demonstrates that the FSC in the rat anterior pituitary responds to Ang Ⅱ by increasing [which raises the possibility that Ang Ⅱ re-leased from either lactotrophs or gonadotrophs affects FSC through paracrine mechanism. The elevation of [induced by Ang Ⅱ presents a dosage-dependent relation, and is possibly because of the release of from an intra-cellular pool (s). Fashions of release are relative to the concentration of Ang Ⅱ. The results indicate that Ang Ⅱ functions as a paracrine factor among pituitary cells including FSC.     

垂体移植对去垂体大鼠的生理功能和靶腺的影响

将体重１５０ｇ～２００ｇ的ＳＤ大鼠随机分成４组，Ⅰ：对照组，Ⅱ：去垂体组，Ⅲ：肌肉移植组，Ⅳ：第Ⅲ脑室移植组。Ⅱ、Ⅲ、Ⅳ组术后３０ｄ的死亡率分别为５０％、１６．７％、３０％，６０ｄ的存活率分别为１１．８％、６６．７％、６０％。结果提示：垂体移植可提高去垂体大鼠的应激性，并延长寿命。在２个半月的时间内，Ⅰ组体重增加１５８．６±５７．２ｇ，Ⅱ组减少３８．５±１１．２ｇ，相反在肌肉和第Ⅲ脑室移植垂体后Ⅲ组体重增加４７．０±３４．３ｇ，Ⅳ组增加５４．８±３６．２ｇ。这说明：植入二部位的垂体可分泌几乎等量的ＧＨ，但其量还远未达到正常水平。Ⅰ组体温波动于３８．１±０．１３℃，而Ⅱ组降低１．８℃，但在移植垂体后，Ⅲ、Ⅳ组的体温均有回升。冷应激试验表明：Ⅰ组的体温均在１．５ｈ内恢复，而Ⅱ组在６ｈ尚未恢复，但Ⅲ、Ⅳ组的体温均在大约２．５ｈ内得以恢复。Ⅲ、Ⅳ组肾上腺、性腺的重量较Ⅱ组明显增加，但仍较Ⅰ组有所减少。在形态上，Ⅱ组的肾上腺、性腺均严重萎缩，但在Ⅲ、Ⅳ组均有一定程度的恢复。由于技术上的原因，在肌肉内未找到移植的垂体，但在第Ⅲ脑室都可看到成活的垂体，其细胞形态正常。ＲＩＡ技术测定表明：Ⅲ组血中的ＴＳＨ接近正常水平。     

不同固定方法对下丘脑和垂体形态学的作用

本文对经主动脉灌注固定和浸泡固定处理的大鼠下丘脑和垂体进行了组织学、细胞化学和超微结构的比较观察。结果表明,灌注固定时,脑及垂体迅速、全面、均匀固定,细胞形态结构正常。而浸泡固定时,固定液之渗入相当缓慢,下丘脑出现许多暗神经元;有的细胞核变形、固缩,少数细胞胞质内空泡形成;细胞内酸性磷酸酶活性增强,酶反应产物融合。这些变化以深部结构更为显著。垂体光镜下形态结构与灌注固定者差别不大,电镜下出现暗细胞,有些细胞内线粒体肿胀,嵴消失,内质网扩张呈泡状,核周隙明显扩大。对上述形态学变化的原因以及方法学的问题进行了讨论。     

一氧化氮对培养的大鼠垂体组织催乳素释放的影响

将大鼠垂体组织培养于 KRB缓冲液中并加入不同浓度的一氧化氮生成抑制剂 L-硝基精氨酸甲酯或一氧化氮供体硝普钠 ,孵育 60 min,收集 KRB。用放射免疫法测定 KRB中催乳素的含量。结果显示 :L-硝基精氨酸甲酯和硝普钠能以剂量依赖性方式刺激和抑制垂体组织释放催乳素 ,提示一氧化氮对催乳素的分泌有抑制作用