脑缺血再灌注对大鼠下丘脑-垂体-肾上腺-胸腺轴的影响

为探讨脑缺血再灌注损伤对大鼠神经-内分泌和免疫功能的影响,本研究采用免疫组织化学和放射免疫等实验技术,从形态、结构和功能三个层次观察了脑缺血再灌注损伤时大鼠下丘脑-垂体-肾上腺-胸腺(HPAT)轴的变化。结果发现:脑缺血后6h、9h组大鼠垂体重量明显减轻;其下丘脑和垂体激素分泌细胞数量减少,体积缩小;脑缺血后血浆CRH、ACTH和CORT浓度呈一致性先短暂升高后持续下降,T细胞增殖能力、T细胞克隆形成率和IL-2活性明显下降,且上述改变缺血9h组重于6h组。当脑缺血恢复再灌注时,缺血3h再灌注组比缺血6h再灌注组恢复快。以上结果表明:①脑缺血再灌注时,HPAT轴先出现一短暂的激活过程,继而很快转入抑制状态;②脑缺血再灌注损伤后大鼠免疫功能受抑制;③缺血后恢复再灌注早,HPAT轴受损轻,恢复快。     

褪黑素水平对抑郁症患者下丘脑-垂体-肾上腺轴功能的影响

目的探讨抑郁症患者褪黑素(MT)水平对下丘脑-垂体-肾上腺轴(HPA)功能的影响。方法对86例抑郁症患者,检测血清MT、促肾上腺皮质激素释放激素(CRH)、促肾上腺皮质激素(ACTH)、皮质醇(COR),并分析其相互关系。结果1以MT中位数(51.3ng/L)为切点,将所有抑郁症患者分为MT高值组(51.3ng/L,n=43)与MT低值组(51.3ng/L,n=43),前者血清CRH、ACTH、COR均显著低于后者(t=3.330,3.315,2.314;P0.01,0.01,0.05);2血清MT水平与CRH、ACTH水平负相关(r=-0.414,-0.329;P0.01,0.05)。结论褪黑素对抑郁症患者的HPA轴功能可能有一定的抑制作用。     

褪黑素对创伤后应激障碍大鼠下丘脑-垂体-肾上腺轴的影响

目的:探讨褪黑素(MLT)对足部电击所致创伤后应激障碍(PTSD)大鼠下丘脑-垂体-肾上腺(HPA)轴的影响。方法:利用足底电击法制备大鼠PTSD模型,通过腹腔注射方法给予治疗组大鼠MLT。通过拒俘反应测试检测大鼠的行为学变化,利用real time RT-PCR方法检测下丘脑中促肾上腺皮质激素释放激素(CRH)mRNA的表达,利用酶联免疫吸附试验(ELISA)检测血清中促肾上腺皮质激素(ACTH)、肾上腺素(EPI)和糖皮质激素(GC)的含量。结果:PTSD组大鼠拒俘反应明显(P<0.05),下丘脑中CRH mRNA表达升高(P<0.05),血清中ACTH和EPI明显升高(P<0.05),但是GC水平下降(P<0.05)。MLT治疗后可以明显缓解PTSD大鼠拒俘反应(P<0.05),同时降低下丘脑中CRH mRNA表达(P<0.05),降低血清中ACTH和EPI水平并升高GC的水平(P<0.05)。结论:MLT治疗可缓解PTSD大鼠的症状,并恢复HPA轴的神经内分泌平衡。     

下丘脑-垂体-肾上腺轴与糖尿病

1型和2型糖尿病患者表现为糖皮质激素分泌过多和下丘脑-垂体-肾上腺轴(HPA轴)功能改变。糖尿病HPA轴功能障碍在中枢和外周水平都有发生,且与长期慢性应激、胰岛素抵抗等相关,另外一些脂肪细胞产物及调节因子也可能参与其中。HPA轴功能异常可能促使糖尿病发生,但也可能是糖尿病造成的后果,不管因果如何糖皮质激素的增加对糖尿病控制是不利的。     

中国劲酒对肾阳虚模型大鼠下丘脑-垂体-肾上腺轴及免疫功能的影响

目的:研究中国劲酒对皮质酮致肾阳虚模型的大鼠下丘脑-垂体-肾上腺(Hypothalamic-pituitary adrenal,HPA)轴及免疫功能的影响。方法:取健康清洁级雄性SD大鼠45只,按随机数字表法分为空白对照组、模型组和中国劲酒组,每组15只,通过皮下注射外源性皮质酮(10 mg/kg体重)连续14天抑制HPA轴,制备肾阳虚模型。皮质酮注射前5天,以50 ml/kg体重灌胃中国劲酒(相当于中国劲酒日推荐服用剂量的30倍),连续19天。采用酶联免疫吸附试验(ELISA)方法检测血浆皮质酮(Corticosterone,CORT)含量;采用放射性免疫法测定血浆中促肾上腺皮质激素(Adrenocorticotropic hormore,ACTH)含量,采用实时定量-聚合酶链反应法(Real-time PCR)测定下丘脑促肾上腺皮质激素释放激素(Corticotropin releasing hormone,CRH)mRNA表达水平;取胸腺称重,淋巴细胞凋亡及增殖率分别采用流式细胞仪法和改良四氮唑盐(XTT)法。结果:在外源性皮质酮作用下,肾阳虚模型大鼠较空白对照组HPA轴和免疫功能受到明显抑制,中国劲酒灌胃后可显著提高大鼠下丘脑CRH mRNA水平、血浆ACTH含量,与肾阳虚模型组比较差异有统计学意义(P<0.05);血浆CORT水平有升高倾向;同时在免疫调节方面,中国劲酒可明显增加皮质酮模型大鼠胸腺重量和降低脾脏淋巴细胞凋亡率,与肾阳虚模型组比较差异有统计学意义(P<0.01);中国劲酒有促进淋巴细胞增殖的趋势。结论:中国劲酒能改善肾阳虚模型大鼠HPA轴功能;也具有改善肾阳虚模型大鼠免疫功能的作用。     

抑郁症患者前扣带回代谢特征与下丘脑-垂体-肾上腺轴活性水平的氢质子波谱研究

目的:用磁共振氢质子波谱的方法探讨抑郁症患者前扣带回(ACC)代谢特征与下丘脑-垂体-肾上腺轴(HPA轴)功能活性的关系.方法:选取68例符合美国精神障碍诊断与统计手册第4版(DSM-Ⅳ)诊断标准的抑郁症患者及30例正常对照,采用磁共振扫描检测前扣带回氢质子波谱N-乙酰天门冬氨酸(NAA)、胆碱(Cho)、肌酸(Cr)、谷氨酸复合物(Glx)及肌醇(mI)等5种代谢物的含量,计算NAA/Cr、Glx/Cr、Cho/Cr、mI/Cr比值.用皮质醇醒觉反应(CAR)检测HPA轴活性,定义为连续2天醒后30 min觉醒时皮质醇浓度差值的均值.根据抑郁症组HPA轴活性均值将抑郁症组分为HPA轴高活性组35例(＞6.6 nmol/L)及HPA轴低活性组33例(≤6.6nmol/L).结果:与正常对照相比,抑郁症患者两侧ACC的NAA/Cr[左侧(1.6±0.5)vs.(2.0±0.5),右侧(1.7±0.4)vs.(2.2±0.5)]和Glx/Cr[左侧(0.1±0.03) vs.(0.1 ±0.03),右侧(0.1±0.01) vs.(0.2±0.04)]较低(均P＜0.05),右侧Cho/Cr较高[(1.5±0.9)vs.(0.9±0.3),P＜0.01];与低HPA轴活性组相比,高HPA轴活性组左侧NAA/Cr较低[(1.6±0.4)vs.(1.7±0.4),P＜0.05],右侧Cho/Cr较高[(1.7±0.2)vs.(1.2±0.1),P＜0.01].结论:抑郁症患者可能存在双侧前扣带回N-乙酰天门冬氨酸、谷氨酸及胆碱等代谢紊乱,高HPA轴活性可能与部分代谢物质存在相关.     

松果体褪黑素与下丘脑-垂体-肾上腺轴的相互作用

近年来很多学者发现松果体褪黑素(MLT)可以通过下丘脑垂体肾上腺轴(HPA)影响机体免疫功能,本文主要列举了松果体MLT对HPA轴三个水平调节的新发现和可能的机制,证实松果体MLT对垂体和肾上腺皮质有明显的调节作用,但对下丘脑是否有调节作用还存在诸多争议,同时也简述了HPA轴对松果体MLT影响研究的新进展,提示二者实际上存在着昏综复杂的相互作用。     

胃复安与下丘脑-垂体-甲状腺轴的关系及临床意义

下丘脑分泌的促甲状腺激素释放激素(Thyrotropin—releasing hormone，TRH)促进垂体促甲状腺激素(Thyrotropin，TSH)的合成和释放，而多巴胺(Dopamine，DA)和生长抑素(Somatostatin，SST)抑制TSH的合成和释放，甲状腺激素也对TSH产生反馈抑制作用。甲状腺功能减退患者，伴随多巴胺能神经元功能(Dopaminergietone)的降低和TSH基础水平升高。胃复安(Metoclopramide，MCP)是多巴胺第二受体拮抗剂，能加速提高甲低患者血TSH水平，特别是当运用于分化型甲癌(Differentiated thyroid carcinoma，DTC)病人时，能缩短停用左旋甲状腺素(L—thyroxine，L—T4)的时间和减轻甲状腺机能减退所致的症状和体征，有助于对DTC病灶的^131I显像诊断和^131I治疗。     

外源性糖皮质激素对大鼠下丘脑—垂体—肾上腺—胸腺轴的影响

本文观察大鼠每在皮下注射皮质酮（１～５０ｍｇ／ｋｇ，连续１４天）后下丘脑－垂体－肾上腺－胸腺（ＨＰＡＴ）轴的形态与机能改变，结果表明：实验大鼠垂体，肾上腺，胸腺重量减轻，下丘脑单胺类递质含量升高，下丘脑室旁核促肾上腺皮质素释放因子（ＣＲＦ）分泌细胞及正中隆起ＣＲＦ神经纤维和垂体前叶促肾上腺皮质激素（ＡＣＴＨ）分泌细胞等数量减少，染色变淡，血浆皮质酮（ＣＯＲＴ）和ＡＣＴＨ浓度降低。淋巴细胞增殖反应及     

The role of hypothalamic hormones in the pathogenesis of pituitary adenomas

There is evidence that hypothalamic hormones can regulate hormone secretion by pituitary adenomas. Hormone release by adenomas can be stimulated by hypothalamic releasing peptides; several hypothalamic inhibitory hormones or their analogues are used in the therapy of pituitary tumors to suppress hormone secretion and, in some cases, to reduce tumor size. A role for hypothalamic hormones in the development and growth of pituitary tumors has also been suggested by the association of pituitary adenomas with tumors producing hypothalamic hormones. In particular, tumors producing growth hormone-releasing hormone (GRH) or corticotropin-releasing hormone (CRH) have been associated with hyperplasia of their target adenohypophysial cells; a few have had pituitary neoplasms. Investigations have shown that some adenohypophysial cells respond to sustained stimulation by hypothalamic peptides with cell proliferation, however, it was not proven that the sustained stimulation resulted in the development of tumors. Recently, an animal model of disease was provided by mice transgenic for GRH. At 8 months of age, the mice developed pituitary mammosomatotroph hyperplasia; mice older than 12 months developed pituitary mammosomatotroph adenoma. It is suggested that continued hormonal stimulation plays a role in tumorigenesis, probably by promotion of cell replication.     

Assessment of hypothalamic pituitary function in endocrine disease

The insulin test carried out with adequate safeguards under standardized conditions yields valuable information regarding hypothalamic and pituitary function when plasma levels of sugar, cortisol, and growth hormone are determined. The use of a test based on the plasma cortisol response to the infusion of lysine-vasopressin, a polypeptide with a corticotrophin-releasing action, is also of value as a test of pituitary function. Used in conjunction with the insulin test it enables pituitary disorders to be differentiated from those involving the hypothalamus.     

The effect of ski training at altitude and racing on pituitary,adrenal and testicular function in men

Summary The effect of similar prolonged exercise on hormonal changes was studied at sea level and at moderate altitude. Four cross-country skiers participated in a 30-km race and five biathlonists in a 20-km race at sea level in Finland and during altitude training and racing at 1650 m in Les Saisies, France. Venous blood samples were taken at both altitudes before the race between 0800 and 0900 hours and 25–35 min after the race. Resting blood samples were also taken before and after the altitude training and the period of racing. Serum testosterone concentration was higher before the race at altitude than at sea level (19%, P<0.02), and 30 min after the race growth hormone (GH) concentration was higher at sea level than at moderate altitude (P<0.002). There were not significant differences in serum luteinising hormone between the altitudes. Serum cortisol concentration was higher after the altitude training and the period of racing than before (P<0.02) but no difference was observed in testosterone. We concluded, that since the profiles of the anabolic-catabolic hormone concentrations measured are indicators of the performance level of athletes, our data indicated that to follow them during altitude training could be beneficial in optimizing training programme for individual athletes. We also concluded, that the lower GH concentration after racing at moderate altitude may have been a consequence of decreased racing speed and/or increased physical performance.     

Does hypothalamic–pituitary–adrenal axis hypofunction in chronic fatigue syndrome reflect a ‘crash’ in the stress system?

The etiopathogenesis of chronic fatigue syndrome (CFS) remains poorly understood. Although neuroendocrine disturbances – and hypothalamic–pituitary–adrenal (HPA) axis hypofunction in particular – have been found in a large proportion of CFS patients, it is not clear whether these disturbances are cause or consequence of the illness. After a review of the available evidence we hypothesize that that HPA axis hypofunction in CFS, conceptualized within a system-biological perspective, primarily reflects a fundamental and persistent dysregulation of the neurobiological stress system. As a result, a disturbed balance between glucocorticoid and inflammatory signaling pathways may give rise to a pathological cytokine-induced sickness response that may be the final common pathway underlying central CFS symptoms, i.e. effort/stress intolerance and pain hypersensitivity. This comprehensive hypothesis on HPA axis hypofunction in CFS may stimulate diagnostic refinement of the illness, inform treatment approaches and suggest directions for future research, particularly focusing on the neuroendocrine–immune interface and possible links between CFS, early and recent life stress, and depression.