下丘脑-垂体-肾上腺轴在抑郁症发病中的作用

越来越多的研究表明，下丘脑一垂体一肾上腺轴(hypothalamic pituitary adrenal axic，HPA轴)在抑郁的发病机制中发挥着重要的作用。HPA轴的活化机制是：下丘脑通过垂体门脉系统运送下丘脑调节肽(促肾上腺皮质激素释放激素，CRH)到脑垂体，从而调节腺垂体的分泌。腺垂体在调节肽的作用下释放促肾上腺皮质激素(ACTH)，然后作用于肾上腺皮质，释放肾上腺皮质激素到全身。下面我们将从HPA轴的三个水平(CRH、ACTH、肾上腺皮质激素)来论述HPA轴在抑郁发病过程中的作用。     

糖尿病缺血性中风证候特征与神经内分泌免疫网络、脑病理改变的关系研究

目的:对Ⅱ型糖尿病(NIDDM)并发急性脑梗死(ACI)的中风证候特征与神经内分泌免疫网络(NEIN)及其相应脑病理改变进行观察研究,以从宏观与微观辨证阐明该病的发病机理.方法:采用中风辨证量表、血液流变学等指标对脑卒中患者始发状态进行评分和放射免疫分析,包括下丘脑-垂体-肾上腺轴(HPA)激素(促肾上腺皮质激素释放激素、促肾上腺皮质激素、皮质醇)与免疫细胞因子(肿瘤坏死因子α、白细胞介素-6)水平变化等,并与正常体检者进行对照.结果:本观察中风证型以风火阳亢证型组HPA轴激素及免疫细胞因子失常最为显著,其血中含量与风痰瘀阻证组及气虚血瘀证组相比,均具有非常重要的统计学意义(P＜0.01～0.001),后两组证型与正常健康组比较也获同样结果(P＜0.05～0.001).结论:Ⅱ型?糖尿病并发急性脑梗死中医证型与神经内分泌免疫网络关系密切,深入研究其变化,将有助于阐明该病的发病机理和提高其微观辨证的诊断水平.     

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。     

强肌健力饮对肾阳虚大鼠CRH、ACTH、Cor水平的影响

目的:观察强肌健力饮对肾阳虚大鼠下丘脑组织中促肾上腺皮质激素释放激素(CRH)及血浆促肾上腺皮质激素(ACTH)、皮质醇(Cor)水平的影响,进一步探讨该方对中医肾阳虚证的防治机理.方法:将大鼠分为正常对照组、肾阳虚模型组、强肌健力饮低、中、高剂量组、右归丸阳性对照组,采用氢化可的松制备肾阳虚大鼠模型.观察动物的一般状态及其胸腺和肾上腺指数,采用放射免疫分析检测CRH、ACTH、Cor的含量.结果:①肾阳虚模型组大鼠体重及胸腺指数、肾上腺指数明显低于正常对照组(P＜0.01),CRH、ACTH、Cor含量均比正常对照组显著降低(P＜0.01).②强肌健力饮各剂量组CRH、ACTH、Cor含量均比肾阳虚模型组显著升高(P＜0.05～0.01).结论:肾阳虚时下丘脑-垂体-肾上腺轴合成、分泌和调控功能低下,而强肌健力饮能够修复该轴功能的损伤,表明该方药具有下丘脑、垂体、肾上腺轴多层次的调节作用.     

急性缺血性中风始发状态风证与垂体-肾上腺轴激素的关系研究

目的 :探讨急性缺血性中风 (急性脑梗死 ,ACI)始发状态风证与垂体 -肾上腺轴激素 (促肾上腺皮质激素ACTH、皮质醇CS)的关系。方法 :采用中风病专家经验辨证量表对 15 1例ACI患者的始发状态进行证候评分 ,同时利用放射免疫分析 (RIA)测定ACTH、CS含量 ,再按证候评分将患者分成风证组与非风证组 ,对比两组患者ACTH、CS的变化水平 ,并与健康人组 (6 0例 )作对照。结果 :①风证组的ACTH、CS水平非常显著地高于非风证组 (p <0 0 0 1) ;风证组与非风证组的ACTH、CS含量与正常健康人组比较也呈上述变化 (p <0 0 0 1) ,②77例风证组患者的风证评分与ACTH含量呈高度正相关关系 (r =0 89、t=14 6 1) ,与CS含量呈中度相关关系(r=0 5 3、t=4 83)。结论 :风证与ACTH、CS具有正相关关系 ,其升高水平可作为判定风证与非风证的微观指标     

外源性ADM对肾脏急性机械性损伤早期HPA轴的影响

目的: 研究外源性肾上腺髓质素(ADM)的运用对肾脏急性机械性损伤早期下丘脑-垂体-肾上腺皮质(HPA)轴的影响,探讨外源性ADM在急性创伤中的生物学作用。方法: 健康成年普通级Wistar大鼠104只,随机分为4组:正常对照组(8只)、单纯创伤组(32只)、伤前给药组(32只)、伤后给药组(32只);后3组采用自由落体打击仪直接打击大鼠脊肋区制作肾脏机械性损伤模型。2个给药组分别于损伤前后10 min腹腔注射ADM(0.1 nmol/kg)。3 组肾损伤大鼠分为4 批分别于创伤后1、6、12、24 h采用快速心脏采血法处死。迅速解剖动物提取下丘脑标本,采用免疫组化染色法检测促肾上腺皮质激素释放激素(CRH)在下丘脑的表达;放免分析法检测血浆促肾上腺皮质激素(ACTH)、皮质醇(CORT)浓度。结果: 单纯创伤组下丘脑CRH的表达及血浆ACTH、CORT浓度较正常对照组轻微升高,但无显著差异;创伤前注射ADM使创伤后下丘脑CRH的表达在1、24 h,血浆ACTH浓度在12 h,以及血浆CORT浓度在6、12、24 h显著高于单纯创伤组及正常对照组(P<0.05);创伤后注射ADM使下丘脑CRH的表达在1、6、12 h,以及血浆CORT浓度在12、24 h明显高于单纯创伤组及正常对照组(P<0.05)。结论: 外源性ADM可激活HPA轴,使HPA轴各个层面的活动增强,但不同层面对外源性ADM的反应性不同,创伤前、后注射ADM对HPA轴的影响不同。     

褪黑素对SD大鼠下丘脑-垂体-肾上腺皮质的影响

目的 研究褪黑素对正常和糖尿病大鼠下丘脑-垂体-肾上腺皮质功能和超微结构的影响.方法 应用放射免疫法分别观察了低、中、高剂量(0.5mg/kg、10mg/kg、50mg/kg)褪黑素及对照药物硫辛酸(100mg/kg)连续腹腔注射3周,对SD大鼠血浆促肾上腺皮质激素释放激素(CRH)、促肾上腺皮质激素(ACTH)、皮质酮(COR)水平的影响.并运用电镜观察用药前后大鼠垂体、肾上腺皮质超微结构的变化.结果 1.正常和糖尿病大鼠低、中、高剂量褪黑素处理组CRH水平与相应对照组相比显著降低;正常大鼠低、中、高剂量褪黑素及硫辛酸处理组和糖尿病大鼠低剂量(0.5mg/kg)褪黑素、硫辛酸处理组ACTH水平比相应对照组明显降低(P＜0.05);正常大鼠低、中、高剂量褪黑素处理组和糖尿病大鼠中高剂量褪黑素处理组皮质酮水平比相应对照组显著降低(P＜0.05).2.褪黑素对正常大鼠下丘脑-垂体-肾上腺皮质超微结构无明显影响.糖尿病大鼠垂体细胞和肾上腺皮质细胞出现功能受抑制状态,褪黑素(50mg/(kg·d))处理21d后垂体促肾上腺皮质细胞和肾上腺皮质细胞代谢较处理前明显活跃.结论 褪黑素能在不同层次直接或间接地发挥对正常和糖尿病大鼠下丘脑-垂体-肾上腺(HPA)轴的抑制作用.     

急性高台应激对大鼠神经内分泌激素、相关受体及脑神经递质的影响

目的 高台应激是一种不可逃避应激,是研究应激对机体神经生理病理变化的重要模型.本研究对急性高台应激后神经内分泌激素、受体表达、脑神经递质变化以及地西泮的干预作用进行探讨.方法 大鼠随机分为空白对照组、应激+地西泮(DAP)组与应激+溶剂组.后两组于应激前30 min分别腹腔注射地西泮2 mg/kg与等量生理盐水.采用酶联免疫法测量应激后各组的血浆促肾上腺皮质激素(ACTH)、血清皮质酮(CORT)水平;采用实时定量PCR测量下丘脑促肾上腺皮质激素分泌激素(CRH)mRNA、海马糖皮质激素受体(GR)mRNA、盐皮质激素受体(MR) mRNA、5-羟色胺1a受体(5-HT1aR)mRNA水平;采用高效液相色谱电化学法测量大脑皮层匀浆液中去甲肾上腺素(NE)、多巴胺(DA)、5-羟色胺(5-HT)及其代谢产物5-羟吲哚乙酸(5-HIAA)水平.结果 与空白组相比,应激+溶剂组大鼠血浆ACTH、血清CORT以及海马5-HT1aR mRNA水平升高(P均＜0.05),此变化可由DAP逆转(P均＜0.05).此外,DAP还可降低应激后的下丘脑CRH mRNA,海马GR mRNA以及MR mRNA水平(P均＜0.05).然而大脑皮层匀浆液中NE、DA、5-HT、5-HIAA在应激后无变化.结论 急性高台应激可引起大鼠相关神经内分泌激素与受体表达变化,且该效应可被DAP逆转.     

下丘脑-垂体-肾上腺轴紊乱对焦虑性抑郁模型大鼠海马结构的影响

目的研究下丘脑-垂体-肾上腺(HPA)轴紊乱对焦虑性抑郁模型大鼠海马结构的影响,探讨焦虑性抑郁的潜在发病机制。方法将大鼠随机分为空白组、溶媒组、焦虑组、抑郁组和焦虑性抑郁组,每组12只。采用慢性束缚应激联合皮质酮注射方法建立焦虑性抑郁大鼠模型,连续21 d;造模后采用高架十字迷宫(EPM)、旷场实验(OFT)、强迫游泳实验(FST)评价大鼠焦虑和抑郁样行为;HE染色检测大鼠HPA轴各组织及海马病理变化;ELISA检测大鼠血浆中促肾上腺皮质激素释放激素(CRH)、促肾上腺皮质激素(ACTH)、皮质酮(CORT)含量;Western blot检测大鼠海马糖皮质激素受体(GR)蛋白表达。结果焦虑性抑郁组大鼠进入开臂的时间、次数及自主活动次数均与焦虑组相当,不动时间显著增加,与对照组及抑郁组比较有显著差异(P0.01或P0.05);HPA轴各组织均出现不同程度损伤,海马神经元肿胀,呈空泡状;同时,血浆中CRH、ACTH和CORT含量显著增加(P0.01或P0.05),海马GR表达显著下降。结论焦虑性抑郁模型组大鼠具有显著的焦虑及抑郁样行为,其发病机制可能与机体HPA轴紊乱及其引发的脑内海马损伤密切相关。     

Thymic Hormones

Abstract

The thymus produces several polypeptides, which induce lymphocyte differentiation in vitro and in vivo. Several of these polypeptides have been chemically characterized, and three of them have been sequenced and synthesised (× 1 thymosin, thymopoietin and the serum thymic factor). Thymic hormones do not act identically on all T-cell subsets : they alter preferentially post-thymic precursor cells, and among mature T cells cytotoxic cells and suppressor cells. Their mode of action at the cellular level involves binding to specific cellular receptors and interaction with adenyl cyclase. Preliminary clinical trials with crude extracts have provided promising results in immunodeficient and cancer patients.

The differentiation of T cells from stem cells has been the matter of considerable investigation over the last two decades, since it has been realized that the thymus and its products, the thymus-derived cells (T cells) play a central role in the generation of effector cells in cell-mediated immunity and in the regulation of the various categories of immune responses. That the thymus could act by the intermediate of humoral substances was precociously suggested by MILLER and OSOBA before the observation that thymuses grafted within a cell-impermeable Millipore diffusion chamber restored the immunocompetence of neonatally thymectomized (Tx) mice (1). However, although this experiment was ultimately confirmed by using chambers with well-controlled impermeability (2), MILLEB did not pursue the idea of the humoral function of the thymus. Probably, the striking results obtained by DAVIES (3) and other workers, indicating direct migration of functional T cells from the thymus and the poor results initially obtained in trying to reconstitute the immune system of neonatally Tx mice by cell-free thymic extracts contributed to this disappointment.

A new impetus was given to the subject in the early 70's when in vitro tests of lymphocyte function became available and when purified extracts of the thymus proved capable of restoring antigen-specific and nonspecific immunocompetence of Tx mice. More recently, completely defined synthetic thymic hormones have been obtained. The question is no longer to decide whether thymic hormones exist, but rather to elucidate their biological significance and potential clinical applications. The multiplicity of available factors has created some confusion. It will be the aim of these few pages to review critically the various factors reported in the literature, giving particular emphasis to their pharmacology and their potential use in the modulation of immune responses.     

Thymic Hormones

The thymus produces several polypeptides, which induce lymphocyte differentiation in vitro and in vivo. Several of these polypeptides have been chemically characterized, and three of them have been sequenced and synthesised (× 1 thymosin, thymopoietin and the serum thymic factor). Thymic hormones do not act identically on all T-cell subsets : they alter preferentially post-thymic precursor cells, and among mature T cells cytotoxic cells and suppressor cells. Their mode of action at the cellular level involves binding to specific cellular receptors and interaction with adenyl cyclase. Preliminary clinical trials with crude extracts have provided promising results in immunodeficient and cancer patients.

The differentiation of T cells from stem cells has been the matter of considerable investigation over the last two decades, since it has been realized that the thymus and its products, the thymus-derived cells (T cells) play a central role in the generation of effector cells in cell-mediated immunity and in the regulation of the various categories of immune responses. That the thymus could act by the intermediate of humoral substances was precociously suggested by MILLER and OSOBA before the observation that thymuses grafted within a cell-impermeable Millipore diffusion chamber restored the immunocompetence of neonatally thymectomized (Tx) mice (1). However, although this experiment was ultimately confirmed by using chambers with well-controlled impermeability (2), MILLEB did not pursue the idea of the humoral function of the thymus. Probably, the striking results obtained by DAVIES (3) and other workers, indicating direct migration of functional T cells from the thymus and the poor results initially obtained in trying to reconstitute the immune system of neonatally Tx mice by cell-free thymic extracts contributed to this disappointment.

A new impetus was given to the subject in the early 70's when in vitro tests of lymphocyte function became available and when purified extracts of the thymus proved capable of restoring antigen-specific and nonspecific immunocompetence of Tx mice. More recently, completely defined synthetic thymic hormones have been obtained. The question is no longer to decide whether thymic hormones exist, but rather to elucidate their biological significance and potential clinical applications. The multiplicity of available factors has created some confusion. It will be the aim of these few pages to review critically the various factors reported in the literature, giving particular emphasis to their pharmacology and their potential use in the modulation of immune responses.     

Assessment of Circulating Hormones in Regulatory Toxicity Studies II. Male Reproductive Hormones

When test article-related testicular toxicity or Leydig cell tumors are identified in nonclinical studies, the measurement of circulating hormones such as luteinizing hormone, follicle-stimulating hormone, inhibin, testosterone, or prolactin is often considered in order to aid mechanistic investigations or to identify potential biomarkers in man. Although some hormone levels are relatively constant, others are subject to wide variability owing to pulsatility of secretion, diurnal rhythms, and stress. To avoid being misled, it is important that this variation is factored into any study design that includes hormone measurements. Since all these possibilities start from the pathologist's reading of the tissue sections, we begin with a review of the morphologic changes that are tied to underlying alterations in hormones. We then provide the reader with basic information and representative hormone data, including coefficients of variation, for the major male reproductive hormones in the three main nonclinical species (rats, dogs, and cynomolgus monkeys). Power and probability tables for rats and dogs allow estimates of the number of animals or samples needed to provide a given likelihood of detecting a hormonal change of a given size. More importantly, we highlight the variability of this process and the real value in readers developing this information at their own site.     

Hormones and breast cancer

The incidence of breast cancer in women varies with age, mammarygland mass and exposure to endogenous and exogenous hormones.Age is the single most important factor and if, as projected,32% of women will be aged >60 years by 2050, world breast cancerincidence will exceed the current 10⁶ per year. Hormonal influencesthat affect growth of the mammary gland increase the risk ofbreast cancer; for example earlier menarche and later menopause.Childbearing protects against later development of breast cancer,and breastfeeding further decreases the risk. The breast cancerrisk declines more with increasing total duration of breastfeeding.Exposure to hormonal contraceptives has been evaluated in acombined reanalysis of data from 51 epidemiological studies.There is a small transient increase in the relative risk ofbreast cancer among users of oral contraceptives but, sinceuse typically occurs at young ages when breast cancer is relativelyrare, such an increase would have little effect on overall incidencerates. In contrast, exposure to menopause hormone treatmentoccurs when the baseline risk of breast cancer is higher, andepidemiological studies and randomized controlled trials consistentlyfind an increase in breast cancer risk with exposure to combinedestrogen and progestogen. Women with a family history of breastcancer in first degree relatives have an increased risk of breastcancer but there is no evidence to suggest that this differsaccording to a woman's use of oral contraceptives or menopausehormone treatment. Selective estrogen receptor modulators areuseful in the treatment and/or prevention of breast cancer dependingon the specific agonist or antagonist effects on estrogen targettissues.