自噬在高磷诱导的大鼠血管平滑肌细胞钙化过程中的作用研究

目的:探讨自噬在高磷诱导的大鼠血管平滑肌细胞(VSMC)钙化过程中的作用。方法:采用磷酸盐(3.2 mmol/L Pi,即高磷状态)建立大鼠VSMC钙化模型。实验分为三组:对照组、钙化组(分为3个亚组:3.2 mmol/L Pi 4d组、3.2 mmol/L Pi 6d组、3.2 mmol/L Pi 8d组);钙化+3-甲基腺嘌呤(3-MA)组(3.2mmol/L Pi 8 d+5 mmol/L 3-MA)。分别通过茜素红S染色法和邻甲酚肽络合酮比色法检测各组细胞钙结节形成及钙含量;蛋白免疫印迹法检测各组细胞转录因子蛋白(Runx2)、α-肌动蛋白(α-SMA)和自噬相关蛋白—膜型微管蛋白1轻链3β(LC3Ⅱ)蛋白表达量。透射电子显微镜观察VSMC内自噬小体形成情况。免疫荧光显微镜下观察VSMC中LC3和Runx2定位表达。结果:与对照组相比,3.2 mmol/L Pi 8 d组钙结节、钙含量、Runx2和LC3Ⅱ蛋白表达量及自噬小体均显著增高,α-SMA蛋白表达量降低,差异具有统计学意义(P0.05)。与3.2 mmol/L Pi 8 d组相比,钙化+3-MA组细胞钙含量增多,LC3荧光分布量降低,Runx2阳性细胞数增多,差异具有统计学意义(P0.05)。结论:自噬在磷酸盐诱导的VSMC钙化过程中具有保护作用。     

吡格列酮通过内质网应激致凋亡途径对大鼠血管平滑肌细胞钙化的影响

目的　探讨吡格列酮通过内质网应激致凋亡途径对大鼠血管平滑肌细胞钙化的影响及机制。方法　利用β-甘油磷酸钠联合丙酮酸钠制备钙化血管平滑肌细胞模型,予不同浓度（10、50、100　μmol/L）吡格咧酮干预。用Von　Kossa　染色、茜素红S染色测定钙含量以及碱性磷酸酶（ALP）活性观察细胞钙化程度。采用流式细胞术及Tunel法检测细胞凋亡率,实时荧光定量PCR及Western　Blot检测各组细胞GRP78、Caspase-12和Runx2的mRNA及蛋白表达。结果　钙化组其钙含量、ALP活性较对照组细胞增多（P<0.05）,而不同浓度吡格列酮呈剂量依赖性地减轻钙化大鼠血管平滑肌细胞的钙含量和ALP活性（P<0.05）;钙化组其细胞凋亡率较对照组明显升高,而不同浓度吡格列酮呈剂量依赖性地减轻钙化大鼠血管平滑肌细胞凋亡率（P<0.05）;钙化组GRP78、Caspase-12和Runx2　的mRNA及蛋白表达明显升高,而不同浓度吡格列酮呈剂量依赖性地下调钙化大鼠血管平滑肌细胞GRP78、Caspase-12和Runx2的mRNA及蛋白表达（P<0.05）。结论　吡咯列酮通过内质网应激致凋亡途径作用可减轻β-磷酸甘油诱导的血管平滑肌细胞钙化,其作用可能与GRP78、Caspase-12及Runx2表达下调有关。     

PFKFB3抑制剂减轻高磷诱导的大鼠血管平滑肌细胞钙化

目的 探究果糖-2, 6-二磷酸酶3(6-bisphosphatase 3, PFKFB3）抑制剂3-PO对高磷诱导大鼠血管平滑肌细胞（vascular smooth muscle cell, VSMC）钙化的作用及其潜在机制。 方法 将原代培养的VSMC随机分为:对照(Con)组、高磷诱导（β-GP）组、高磷诱导+ 3-PO（β-GP +3-PO）组、对照+乳酸钠（Con +Lactate）组、对照+乳酸钠+ 3-PO（Con +Lactate+3-PO）组。实验前后用微板法检测细胞内钙和碱性磷酸酶（ALP）含量;茜素红染色检测VSMC钙化程度;CCK 8试剂盒检测细胞活力;蛋白免疫印迹法（Western blot）检测表型转化相关蛋白(RUNX2, BMP-2, SM22a)及糖酵解相关蛋白(PFKFB3, HKⅡ, GLUT1与GLUT4)表达水平,比色法检测乳酸含量及乳酸脱氢酶（LDH）活力。 结果 与Con组比较,β-GP组VSMC钙化程度及成骨蛋白表达显著增加（P<0.01）,细胞活力显著降低（P<0.01）,而给予3-PO可显著逆转β-GP组的VSMC表型转化蛋白的表达变化（P<0.05）,并使细胞活力增加（P<0.01）。进一步的研究证实,β-GP组中PFKFB3表达水平,乳酸含量及LDH活力显著增加（P<0.01）,而在β-GP +3-PO组中显著下调（P<0.01）,其余糖酵解蛋白表达水平未明显改变。另外,乳酸钠也可引起VSMC钙化程度及表型转化蛋白表达的增加（P<0.01）,给予3-PO可逆转乳酸钠引起的VSMC钙化和表型转化（P<0.05）。 结论 PFKFB3抑制剂3-PO可能通过降低PFKFB3表达抑制糖酵解水平,从而抑制了高磷诱导的VSMC的钙化,研究结果为临床治疗血管钙化提供了潜在的药物靶点。     

BMP信号通路在华法林诱导的大鼠血管平滑肌细胞钙化中的作用

目的探讨骨形态发生蛋白(BMP)信号通路在华法林诱导的大鼠血管平滑肌细胞(VSMC)钙化中的作用。方法体外分离培养大鼠胸主动脉VSMC,将其随机分为正常对照组、高磷组、华法林(10μmol/L)干预组及华法林(10μmol/L)+维生素K(10μmol/L)干预组。对细胞进行钙含量和碱性磷酸酶(ALP)活性检测,茜素红染色检测钙结节,Western blot检测细胞中Runx2蛋白的表达变化,RT-PCR检测细胞中骨形态发生蛋白2(BMP-2)、Smad1及Runx2的表达变化。结果茜素红染色结果显示,与正常对照组和高磷组相比,华法林干预组钙化结节明显增多;钙含量测定结果与茜素红染色结果基本一致。与正常对照组和高磷组相比,华法林干预组ALP活性明显增加(P0.05),Runx2 mRNA和蛋白表达水平及BMP-2、Smad1 mRNA表达明显增高(P0.05);与华法林干预组相比,华法林+维生素K干预组细胞钙含量、ALP活性及BMP-2、Smad1、Runx2的表达均明显降低(P0.05)。结论BMP信号通路参与了华法林促进的大鼠VSMC钙化,其可能的作用机制是介导了VSMC的表型转化。     

酸性环境对高磷诱导的大鼠血管平滑肌细胞钙化的影响及机制研究

目的探讨酸性环境对高磷诱导的大鼠血管平滑肌细胞(VSMCs)钙化的影响及可能机制。方法体外分离培养大鼠VSMCs,采用免疫细胞化学方法鉴定。将VSMCs按随机数字表法分为正常对照组、高磷+p H7.4、高磷+p H7.1和高磷+p H6.8(在高磷培养基的基础上调整p H值为6.8、7.1和7.4三个亚组)。刺激4 d后,采用RT-PCR检测L型钙通道(LTCC)α_(1C)、β_2和β_3亚基,Runt相关转录因子2(Runx2)及Smad1基因的表达;应用钙离子探针Fluo-3/AM检测VSMCs胞外钙离子内流的效应变化。刺激14 d后,对各组细胞进行钙化染色、钙含量和碱性磷酸酶(ALP)活性测定。结果与正常对照组比较,高磷+p H7.4组钙含量、ALP活性、Runx2和Smad1mRNA的表达明显增高(88.26±6.43比22.39±3.19、94.33±3.08比20.39±1.18、0.37±0.02比0.01±0.00、0.65±0.05比0.07±0.01,均为P<0.05);与高磷+p H7.4组比较,高磷+p H7.1组和高磷+p H6.8组的钙含量、ALP活性、Runx2和Smad1mRNA的表达均降低(69.95±1.72和50.74±3.29、51.11±2.05和34.62±1.13、0.25±0.02和0.09±0.01、0.44±0.04和0.23±0.01,均为P<0.05)。与正常对照组比较,高磷+p H7.4组的LTCCβ_3亚基mRNA表达水平增加(0.80±0.01比0.34±0.13,P<0.01),高磷+p H7.1组和高磷+p H6.8组的LTCCβ_3亚基mRNA表达水平均下降(0.64±0.11和0.43±0.01,均为P<0.01)。各组之间LTCCα_(1C)和β_2亚基mRNA的表达差异无统计学意义(P=0.08和0.74)。与正常对照组比较,高磷+p H7.4组的VSMCs胞内钙离子浓度增加(438.33±7.50比149.54±20.89,P<0.05);高磷+p H7.1组和高磷+p H6.8组的VSMCs胞内钙离子浓度均降低(329.66±16.64和234.00±17.43,均为P<0.01)。结论酸性环境可以抑制高磷诱导的大鼠VSMCs钙化,其可能是通过抑制LTCCβ_3亚基表达,降低VSMCs钙离子内流,阻滞VSMCs发生表型转化来实现的。     

间歇性碱刺激对高磷诱导的大鼠血管环钙化的影响及可能机制

目的探讨间歇性碱刺激对高磷诱导的大鼠胸主动脉血管环钙化的影响及可能机制。方法体外分离大鼠胸主动脉血管环,将其随机分为正常对照组、高磷组(含10 mmol/Lβ-甘油磷酸的培养基)和间歇性碱刺激组(在高磷培养基的基础上调整pH值为7.7)。干预14天后,采用免疫组织化学方法检测L型钙通道(LTCC)β3亚基、Runt相关转录因子2(Runx2)和平滑肌蛋白22α(SM22α)的表达情况;采用硝酸银染色法和钙含量测定法检测血管环钙化程度。结果与正常对照组相比,高磷组的钙含量、Runx2和LTCCβ3亚基表达水平均增加(P0.001);与高磷组相比,间歇性碱刺激组的钙含量、Runx2和LTCCβ3亚基表达水平均有显著增加(P0.001)。同时,高磷组棕黑色钙化结节较正常对照组增多,间歇性碱刺激组棕黑色钙化结节较高磷组增多。与正常对照组相比,高磷组的SM22α表达水平下降(P0.001);与高磷组相比,间歇性碱刺激组的SM22α表达水平显著下降(P0.001)。相关性分析显示,LTCCβ3亚基与Runx2蛋白表达呈正相关(r=0.740,P=0.002),与SM22α蛋白表达呈负相关(r=-0.670,P=0.006)。结论间歇性碱刺激可以促进高磷诱导的大鼠胸主动脉血管环钙化,其可能通过上调LTCCβ3亚基表达,促进血管平滑肌细胞向成骨/成软骨表型转化,进而促进血管环钙化的发生。     

基于Klotho/FGF23轴探讨益气活血通络方对高磷诱导血管平滑肌细胞钙化的影响

目的:基于Klotho/成纤维细胞生长因子23(FGF23)轴探讨益气活血通络方对高磷诱导血管平滑肌细胞钙化的影响。方法:制备益气活血通络方含药大鼠血清,并提取和培养原代大鼠胸主动脉血管平滑肌细胞(VSMCs)。采用β-甘油磷酸(β-GP)诱导大鼠VSMCs钙化模型,加入不同浓度的益气活血通络方含药大鼠血清进行干预,实验设置8组：对照组、模型组、益气活血通络方低剂量组(模型+10%含药血清)、益气活血通络方高剂量组(模型+20%含药血清)、益气活血通络方+sh-Klotho组(模型+20%含药血清+sh-Klotho)、益气活血通络方+阴性对照质粒(sh-NC)组(模型+20%含药血清+sh-NC)、益气活血通络方+成纤维细胞生长因子23基因过表达腺病毒(Ad-FGF23)组(模型+20%含药血清+Ad-FGF23)、益气活血通络方+重组腺病毒空载体(AdLaz)组(模型+20%含药血清+AdLaz)。显微镜下观察VSMCs的形态学变化并采用α-平滑肌肌动蛋白(α-SMA)免疫荧光染色鉴定大鼠VSMCs;细胞计数(CCK-8)法检测细胞增殖情况;茜素红S染色观察钙结节的形成情况;按照钙...     

雌激素通过磷脂酰肌醇3-激酶/蛋白激酶B信号转导途径对钙诱导的大鼠血管平滑肌细胞钙化的影响

目的研究雌激素对血管平滑肌细胞钙化的影响及机制。方法体外培养大鼠胸大动脉平滑肌细胞(A7r5),按CaCl2溶液不同时间和浓度梯度进行钙化模型建立。细胞随机分为正常对照组、钙化组、雌激素干预(钙化+雌激素)组、雌激素溶剂对照(钙化+Eth)组、磷脂酰肌醇3-激酶(phosphatidylinositol3-kinase,PI3K)/蛋白激酶B(protein kinase B,Akt)信号转导通路拮抗剂干预(钙化+LY294002)组。对不同处理组细胞采用茜素红染色检测钙化结节,酶联免疫吸附试验(ELISA)法检测细胞钙离子浓度及碱性磷酸酶(alkaline phosphatase,ALP)活性;实时聚合酶链反应(RT-PCR)检测Runx2的m RNA浓度,Western blot检测Runx2及磷酸化(phosphate,p)-Akt的表达水平。结果与正常对照组相比,钙化组A7r5细胞的茜素红染色钙化结节、钙离子浓度、ALP活性、Runx2的mRNA浓度和Runx2、P-Akt蛋白浓度明显升高,差异有统计学意义(P0.01)。与钙化组A7r5细胞相比,雌激素干预后明显抑制A7r5细胞钙化(P0.01),并降低Runx2、P-Akt蛋白浓度,差异有统计学意义(P0.05)。结论雌激素可通过抑制A7r5细胞钙化过程中PI3K/Akt信号通路及下游的Runx2表达,从而抑制细胞钙化。     

细胞外酸碱环境对主动脉瓣膜间质细胞钙化的影响及相关机制研究

目的探究细胞外酸碱环境对主动脉瓣膜间质细胞钙化的影响及相关机制。方法主动脉瓣膜来源于2017年1—6月在第二军医大学附属长海医院心血管外科接受心移植手术的患者,采用二次胶原酶消化法分离主动脉瓣膜间质细胞,采用细胞免疫荧光法和流式细胞术鉴定主动脉瓣膜间质细胞。将传代的主动脉瓣膜间质细胞随机分为A、B、C、D 4组,A组采用普通培养基培养,p H值为7.4,B、C、D组均采用普通培养基+钙化培养基培养,p H值分别为7.1、7.4、7.7。采用实时荧光定量聚合酶链反应(PCR)检测4组细胞骨形态发生蛋白2(BMP-2)、Runt相关转录因子2(Runx2)和碱性磷酸酶(ALP)mRNA表达情况,采用Western Blot法检测4组细胞BMP-2、Runx2蛋白表达情况,采用比色法检测4组细胞ALP活性,采用茜素红染色观察4组细胞钙化结节情况。结果 (1)细胞免疫荧光法检测结果显示,波形蛋白(Vimentin)阳性率接近100%。流式细胞术检测结果显示,细胞CD31阳性率为1.17%。(2)将A组作为对照,C、D组细胞BMP-2、Runx2和ALP mRNA相对表达量高于B组,D组细胞BMP-2、Runx2和ALP mRNA相对表达量高于C组(P0.05)。(3)B、C、D组细胞BMP-2、Runx2蛋白相对表达量高于A组,C、D组细胞BMP-2、Runx2蛋白相对表达量高于B组,D组细胞BMP-2、Runx2蛋白相对表达量高于C组(P0.05)。(4)B、C、D组细胞ALP活性高于A组,C、D组细胞ALP活性高于B组,D组细胞ALP活性高于C组(P0.05)。(5)茜素红染色结果显示,A组细胞钙化结节较少,B、C、D组细胞钙化结节逐渐增多;与C组相比,B组钙化结节明显减少,D组钙化结节明显增多。结论细胞外酸性环境可抑制主动脉瓣膜间质细胞钙化,碱性环境则可促进主动脉瓣膜间质细胞钙化,其机制可能与细胞外酸碱环境影响BMP-2信号通路有关。     

Three layer functional model and energy exchange concept of aging process

Relying on a certain degree of abstraction, we can propose that no particular distinction exists between animate or living matter and inanimate matter. While focusing attention on some specifics, the dividing line between the two can be drawn. The most apparent distinction is in the level of structural and functional organization with the dissimilar streams of ‘energy flow’ between the observed entity and the surrounding environment. In essence, living matter is created from inanimate matter which is organized to contain internal intense energy processes and maintain lower intensity energy exchange processes with the environment. Taking internal and external energy processes into account, we contend in this paper that living matter can be referred to as matter of dissipative structure, with this structure assumed to be a common quality of all living creatures and living matter in general. Interruption of internal energy conversion processes and terminating the controlled energy exchange with the environment leads to degeneration of dissipative structure and reduction of the same to inanimate matter, (gas, liquid and/or solid inanimate substances), and ultimately what can be called ‘death.’ This concept of what we call dissipative nature can be extended from living organisms to social groups of animals, to mankind. An analogy based on the organization of matter provides a basis for a functional model of living entities. The models relies on the parallels among the three central structures of any cell (nucleus, cytoplasm and outer membrane) and the human body (central organs, body fluids along with the connective tissues, and external skin integument). This three-part structural organization may be observed almost universally in nature. It can be observed from the atomic structure to the planetary and intergalactic organizations. This similarity is corroborated by the membrane theory applied to living organisms. According to the energy nature of living matter and the proposed functional model, the decreased integrity of a human body's external envelope membrane is a first cause of the structural degradation and aging of the entire organism. The aging process than progresses externally to internally, as in single cell organisms, suggesting that much of the efforts towards the restoration and maintenance of the mechanisms responsible for structural development should be focused accordingly, on the membrane, i.e., the skin. Numerous reports indicate that all parts of the human body, like: bones, blood with blood vessels, muscles, skin, and so on, have some ability for restoration. Therefore, actual revival of not only aging tissue of the human body's membrane, but the entire human body enclosed within, with all internal organs, might be expected. We assess several aging theories within the context of our model and provide suggestions on how to activate the body's own anti-aging mechanisms and increase longevity. This paper presents some analogies and some distinctions that exist between the living dissipative structure matter and inanimate matter, discusses the aging process and proposes certain aging reversal solutions.     

Unusual responses of nocturnal pineal melatonin synthesis and secretion to swimming: Attempts to define mechanisms

Abstract: The effect of swimming at night on rat pineal melatonin synthesis was compared with that of light exposure at night. Rats were forced to swim at 0030 hr (lights out at 2000 hr) and sacrificed by decapitation 15 and 30 min later, immediately after swimming. Other groups of animals were exposed to white light (650μW/cm²) for 15 and 30 min at same time. Swimming caused a rapid and highly significant drop in the melatonin content in the pineal gland; however, the activity of N-acetyltransferase (NAT), the supposed rate limiting enzyme in the melatonin production, was not changed. Despite the drop in pineal melatonin levels, serum concentrations of the indole remained elevated in the rats that swam. In contrast, melatonin levels in the pineal and serum of light exposed rats fell precipitously, accompanied by a significant suppression of NAT activity. Since we anticipated that the strenuous exercise associated with swimming may induce release of artrial natriuretic peptide (ANP) from the heart, which in turn could cause the release of pineal melatonin, in a second study we injected physiological saline intravenously to stretch the cardiac muscle and release ANP. Three milliliters of normal saline was injected during the day into the jugular vein of anesthetized rats that were pretreated with isoproterenol to stimulate pineal melatonin production. Animals were killed 15 min after the saline injection, and pineal NAT activity and pineal melatonin levels were measured. The saline injections caused no alteration in the elevated levels of either NAT or melatonin. These data suggest that the disparity in pineal NAT activity (which was high) and pineal melatonin (which was low), in animals swum at night, may not be caused by ANP which is released during strenuous exercise such as swimming.     

The immunoneuroendocrine role of melatonin

Abstract: A tight, physiological link between the pineal gland and the immune system is emerging from a series of experimental studies. This link might reflect the evolutionary connection between self-recognition and reproduction. Pinealectomy or other experimental methods which inhibit melatonin synthesis and secretion induce a state of immunodepression which is counteracted by melatonin. In general, melatonin seems to have an immunoenhancing effect that is particularly apparent in immunodepressive states. The negative effect of acute stress or immunosuppressive pharmacological treatments on various immune parameters are counteracted by melatonin. It seems important to note that one of the main targets of melatonin is the thymus, i.e., the central organ of the immune system. The clinical use of melatonin as an immunotherapeutic agent seems promising in primary and secondary immunodeficiencies as well as in cancer immunotherapy. The immunoenhancing action of melatonin seems to be mediated by T-helper cell-derived opioid peptides as well as by lymphokines and, perhaps, by pituitary hormones. Melatonin-induced-immuno-opioids (MHO) and lymphokines imply the presence of specific binding sites or melatonin receptors on cells of the immune system. On the other hand, lymphokines such as -γ-interferon and interleukin-2 as well as thymic hormones can modulate the synthesis of melatonin in the pineal gland. The pineal gland might thus be viewed as the crux of a sophisticated immunoneuroendocrine network which functions as an unconscious, diffuse sensory organ.     

Melatonin and photoperiodic time measurement: Seasonal breeding in the sheep

Abstract: Well-established circadian physiology supports the view that photoperiodic time measurement utilizes the coincidence between the presence of light and a photosensitive phase of a 'biological clock' to alter reproductive status—the so-called external coincidence model of seasonal breeding. In this review, we examine the mechanism whereby photoperiod interacts with presumed suprachiasmatic nuclei activity to allow endogenous melatonin to normally synchronize reproductive activity to the optimal time of year. The Romney Marsh sheep is particularly explored as an experimental model. It is suggested that the on/off activity of seasonal reproduction may be a robust mechanism able to be predictably manipulated by the judicious use of the light/dark cycle and exogenous melatonin, but firmly based on circadian principles.     

Response of rat pineal melatonin to calcium, magnesium, and lithium is circadian stage dependent

Abstract: Herein we documented the response of pineal melatonin production to electrolytes known to be effective on pineal function in view of a possible circadian stage dependence. We studied the release of melatonin by perifused rat pineal glands at 2 different circadian stages corresponding to the middle of the light and dark periods, i.e., respectively, 7 and 19 HALO (Hours After Light Onset, L:D = 12:12). The initial efflux rates were, as expected, much higher in the perifusates of glands removed from rats sacrificed during the dark phase than of those removed during the light phase. After 3 hr of perifusion, melatonin release reached similar levels which were found constant up to the 8th hr of perifusion, whatever the circadian stage. Perifusion of the glands with physiological concentrations for the rat of calcium (5.2 mmol/1) and magnesium (1.34 mmol/1) resulted in a stimulatory effect on the pineal glands removed from rats sacrificed in the middle of the dark period (19 HALO), whereas no effects were observed on the pineal glands removed from rats sacrificed during the light (7 HALO). Lithium (0.28 and 0.55 mmol/1) was ineffective on melatonin release in pineal glands removed 7 and 19 HALO. Our results show differences in the initial efflux rates of melatonin and in the response of perifused pineal glands to calcium and magnesium according to the circadian stage.     

Conservative management of perforated duodenal diverticulum： A case report and review of the literature

Duodenal diverticula are a relatively common condition. They are asymptomatic, unless they become complicated, with perforation being the rarest but most severe complication. Surgical treatment is the most frequently performed approach. We report the case of a patient with a perforated duodenal diverticulum, which was diagnosed early and treated conservatively with antibiotics and percutaneous drainage of secondary retroperitoneal abscesses. We suggest this method could be an acceptable option for the management of similar cases, provided that the patient is in good general condition and without septic signs.     

Changes in connexin43, the gap junction protein of astrocytes, during development of the rat pineal gland

Abstract: The abundance of gap junctions between rat pineal astrocytes formed by connexin43 (Cx43) was studied during development. Levels and distribution of Cx43 were measured by immunoblotting and indirect immunofluorescence, respectively. The amount of Cx43 in cells located within the gland was low until about the 7th postnatal day and increased to adult values between the 14th and 21st days postpartum. Although astrocytes, recognized by their vimentin immunoreactivity, were scarce before birth, they were abundant by the 7th postnatal day suggesting that the low levels of Cx43 found at this age corresponded to a low expression of this protein. Localization of the immunoreactivity to Cx43 and vimentin showed a close correlation, indicating that mature or immature pineal astrocytes form gap junctions made of Cx43. Since Cx43 levels attained their adult values at about the time the innervation and the functional state of the gland reached maturity (2–3 weeks after birth), it is proposed that astrocyte gap junctions are involved in the function of the adult rat pineal gland.     

Presence of immunoreactive growth hormone and prolactin in the ovine pineal gland

Abstract: The use of antisera raised against bovine growth hormone (GH) and ovine prolactin (PRL) enabled the detection of related immunoreactive (ir) sequences of proteins in ovine pineal tissue. The isolation of PRL-like ir-material was accomplished using a 0.25 M ammonium sulphate (pH 5.5) extraction followed by ethanol precipitation, whereas the resulting 2.0 M ammonium sulphate (pH 7.0) precipitate contained a GH-like immunoreactivity. Gel chromatography of the GH-like immunoreactivity (Sephadex G-100) indicated the presence of several GH-like fragments ranging in the M_r range of 7,000 to 55,000. Analyses of the PRL-like ir-material found in pineal tissue on HPLC using a TSK 545-DEAE column led to the resolution into a single peak of immunoreactivity. A single peak of activity was also observed following chromatofocusing and hydrophobic interaction chromatography of the ir-peak from the TSK 545-DEAE column. The PRL-like ir-material inhibited the binding of [¹²⁵I]ovine PRL-S14 to anti-ovine PRL antibodies without showing an affinity for binding to anti-rat PRL or anti-bovine GH antibodies. Scatchard analysis of the binding of pineal PRL-like ir-material and pituitary ovine PRL-S14 to liver membranes from day-20 pregnant rats revealed similar affinity constants (K_a of 4.7 ± 0.2 × 10⁹ M^-1). In addition, the replication of Nb 2 Node rat lymphoma cells was stimulated by pineal PRL-like ir-material, an effect known to be specific for lactogenic hormones. The pineal PRL-like immunoreactivity appeared on sodium dodecyl sulfate polyacrylamide gels as a single major band of M_r 24,000. The functional status of PRL-and GH-like ir-material in the ovine pineal remains to be determined, but evidence is presented that the overall protein synthesis rate of the rat pineal responded to circulating concentrations of PRL.