The Hypothalamic-Pituitary-Thyroid (HPT) Axis in Birds and Its Role in Bird Development and Reproduction

This article reviews thyroid function and its hypothalamic-pituitary-thyroid (HPT) axis control in birds with emphasis on the similarities and differences in thyroid function compared to mammals and other vertebrate classes. Thyroid hormones are important in metabolism and the thermogenesis required for homeothermy in birds, as in mammals, the other homeothermic class of vertebrates. Thyroid hormones play important roles in development and growth in birds, as is the case for all vertebrate classes. The developmental effects of thyroid hormones in birds are presented in the context of differences in precocial and altricial patterns of development and growth with emphasis on oviparous development. The sections on thyroid hormone actions include discussion of effects on the development of a number of tissue types as well as on seasonal organismal processes and interactions of the thyroid axis with reproduction. The current picture of how environmental chemicals may disrupt avian thyroid function is relatively limited and is presented in the context of the assessment endpoints that have been used to date. These endpoints are categorized as thyroid and HPT axis endpoints versus target organ endpoints. The final section discusses two recommended assay protocols, the avian two-generation toxicity assay and the avian one-generation assay, and whether these protocols can evaluate thyroid disruption in birds.     

The endocrine effects of mercury in humans and wildlife

Mercury (Hg) is well studied and research continues as our knowledge of its health risks increases. One expanding area of research not well emphasized to date is the endocrine effects of Hg. This review summarizes the existing literature on the effects of Hg on the endocrine system and identifies gaps in the knowledge. It focuses on the thyroid, adrenal, and reproductive systems, including the accumulation of Hg in the endocrine system, sex differences that are manifested with Hg exposure, reproductive effects in male and female animals including humans, and Hg effects on the thyroid and adrenal systems. We concluded that there are five main endocrine-related mechanisms of Hg across these systems: (a) accumulation in the endocrine system; (b) specific cytotoxicity in endocrine tissues; (c) changes in hormone concentrations; (d) interactions with sex hormones; and (e) up-regulation or down-regulation of enzymes within the steroidogenesis pathway. Recommendations for key areas of research to better understand how the endocrine effects of Hg affect human and wildlife health were developed, and include increasing the amount of basic biological information available about Hg and wildlife species, exploring the role of Hg in the presence of other stressors and chemicals, understanding sublethal and indirect effects of Hg on adverse outcomes, developing better methods to extrapolate effects across species, and understanding the effects of Hg on multiple organ systems following exposure of an animal. Greater inclusion of endocrine endpoints in epidemiological and field studies on humans and wildlife will also advance the research in this area.     

Alterations in hypothalamic-pituitary-adrenal/thyroid (HPA/HPT) axes correlated with the clinical manifestations of depression

The alterations of hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-thyroid (HPT) axes are important neuroendocrine abnormalities in depression. We aimed to identify some potential associations between these alterations and the clinical manifestations of depression in a sample of Chinese origin. 565 depressed patients of Chinese Han region were collected and seven kinds of hormones in HPA and HPT axes were detected. A 17-item Hamilton Depression Rating Scale (HAMD-17) and a 14-item Hamilton Anxiety Rating Scale (HAMA-14) were used to evaluate the baseline condition of each patient. 519 patients were enrolled into analysis. The patients with dysfunction of HPA axis had susceptibility to agitation symptoms (HAMD9 item) and cognitive disorders (HAMD2, 3 and 9 items), while those with normal function of HPA axis had susceptibility to shallow sleep (HAMD5 item). The patients with dysfunction of HPT axis had susceptibility to difficulty in falling asleep (HAMD4 item), weight loss (HAMD16 item) and gastrointestinal symptoms (HAMD12 item). Besides, the patients with dysfunctions of both HPA and HPT axes showed remarkable retardation symptoms (HAMD8 item). These findings might provide some evidences for the clinical subgrouping and management individualization of depressed patients according to the neuroendocrine alterations.     

抑郁症患者神经内分泌节律变化的对照研究

目的 探讨抑郁症患者下丘脑-垂体-肾上腺(HPA)轴、下丘脑-垂体-甲状腺(HPT)轴的功能和节律变化与临床症状晨重夕轻之间的关系.方法 采用放射免疫法对49例符合美国精神障碍诊断与统计手册第4版(DSM-Ⅳ)重性抑郁发作患者及38例对照组,对早7:00、晚7:00血浆皮质醇(CORT)、促肾上腺皮质激素(ACTH)、三碘甲状腺原胺酸(T3)、四碘甲状腺原胺酸(T4)、甲状腺刺激素(TSH)水平进行测定,采用多因素方差分析比较2组各项指标的变化、并与临床症状之间的关系进行分析.结果 病例组早晨血浆CORT、早晨、晚间TSH水平[分别为(365.94±120.78)nmol/L,(6.24±2.47)μIU/ml,(6.68±2.42)±IU/ml]较对照组[(284.91±83.39)nmol/L,(3.82±1.75)±IU/ml,(4.01±1.69)μIU/ml]明显增高,差异有显著性(P<0.05);病例组早晨、晚间血浆T4水平较对照组显著降低(P<0.05);血浆皮质醇水平的早晚变化在病例组与对照组之间差异有显著性(P<0.001);病例组血浆CORT、T3、T4、TSH水平的早晚变化在单相和双相抑郁障碍、伴有和不伴有精神病性症状的临床亚型之间均差异无显著性(均P>0.05).结论 抑郁症患者血浆皮质醇水平存在早晚异常变化,可能是抑郁症的一项特异的生物学标志.     

Clinical and microstructural aberrations of enamel of deciduous and permanent teeth in patients with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy

Objective

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) causes multiple endocrine deficiencies, oral candidiasis and different forms of ectodermal dystrophy including enamel hypoplasia, documented in permanent teeth. Our purpose was to examine dental aberrations associated with APECED, including possible manifestations in primary teeth.

Design

We studied clinically, radiographically, and by scanning electron microscopy (SEM) teeth of children belonging to two APECED families with different mutations in the AIRE gene.

Results

In addition to enamel defects in the permanent teeth we observed hypoplastic pits and hypomaturated patches in the deciduous teeth with underlying changes in the prismatic ultrastructure. The enamel of the permanent molars exhibited a layered arrangement with included whirl-like formations.

Conclusions

Our findings confirm that APECED causes enamel defects that are individually but chronologically distributed, and can alter enamel development early enough to affect deciduous teeth.     

Preparation of monoclonal antibody against HPT and its application to detecting marker protein in genetically modified rice

INTRODUCTION The enzyme hygromycin B phosphotransferase(HPT) is a selectable marker used widely in variousanimal and plant transformation systems. It hasproven that hpt is a highly effective marker gene forrice transformation in comparison with the traditionalkanamycin antibiotic gene (nptII)[1]. On the otherhand, cowpea trypsin inhibitor from cowpea seeds[2],a member of the serine protease inhibitor family, isresistant to a wide range of insects. Constitutiveexpression of the cpti gene…     

Pituitary volume in patients with panic disorder

Panic patients have many functional deficiencies in the hypothalamic-pituitary-adrenal (HPA) axis. Previous studies have shown changed pituitary gland volume in some psychiatric disorders that have functional deficiencies in the HPA axis. However, to date no study has evaluated the pituitary gland volume in patients with panic disorder (PD). We investigated the pituitary gland volume in patients with PD (n = 27) and age- and sex-matched healthy controls (n = 27), using 1.5-T magnetic resonance imaging in this study. Analysis showed that patients with PD had significantly smaller pituitary volume compared to healthy subjects. Patients with agoraphobia especially had a significantly smaller pituitary volume than patients without agoraphobia. There was a significant relationship between the pituitary volume and both the severity of symptoms and the illness duration in the patient group. The results show that patients with PD have reduced pituitary volume, which may reflect the functional abnormalities seen in this disorder. These findings may help us better understand the pathology of PD.     

A combination therapy of vitamin K1 and bile acid on hemorrhagic diathesis in patients with decompensated liver cirrhosis

This paper presents a study of treatment involving vitamin K₁ (VK₁) accompanied by bile acids for hemorrhagic diathesis that was applied 42 times in 35 patients with decompensated liver cirrhosis. The hepaplastin test (HPT) value showed no change during the administration of VK₁ alone. The HPT value elevated significantly, however, after the administration of VK₁ with bile acid, expecially when using ursodeoxycholic acid (UDCA). The HPT value in patients treated with VK₁ in addition to UDCA before treatment with 53.2% ± 10.2% (mean ± SD) and after that for 2.1 ± 1.1 months (mean ± SD) with 74.7 ± 16.8% showed a significant difference (p< 0.001). On the other hand, no significant difference was noted between the HPT value of 57.2 ± 13.6% before and that of 62.9 ± 13.9% after the treatment in patients treated using VK₁ in conjunction with chenodeoxycholic acid (CDCA). These results indicate that the therapy incorporating VK₁ and bile acid, especially UDCA, is useful for reducing the hemorrhagic tendency in patients with decompensated liver cirrhosis who show no improvement using VK₁ alone.     

转sck基因水稻中标记基因表达蛋白HPT食用安全性的初步研究

目的针对抗虫转sck基因水稻中标记基因表达蛋白HPT的食用安全性开展初步研究,主要包括该蛋白在大米中的定性、定量研究、可能的膳食摄入量估计及其潜在致敏性评估等。方法将HPT的编码序列插入带有组氨酸标签(His-tag)的原核表达载体PBV222中进行融合表达,通过脲变性和镍柱亲和层析的方法纯化融合蛋白。用纯化后的6His-HPT蛋白免疫家兔和小鼠,分别制备相应的抗HPT多克隆和单克隆抗体,进一步将这两种抗体组成双抗夹心酶联免疫检测体系,用于检测HPT在转sck基因水稻中的表达水平。在致敏性评估方面,首先将HPT序列与已知的致敏原数据库进行比较,再利用模拟的胃肠液环境进行体外消化稳定性实验。结果重组体经表达纯化后获得了高纯度(95%)的6His-HPT融合蛋白,免疫动物后获得了高效价的抗HPT多克隆及单克隆抗体,经免疫印迹检测证明所制备的抗体可与转基因水稻中及纯化出的HPT蛋白形成特异结合带。由这两种抗体组成的双抗夹心酶联免疫检测体系用于检测HPT抗原时的灵敏度为30ng/ml,可检测出转sck基因水稻叶片中HPT蛋白的表达量约为80~150ng/ml;而在相应的转基因大米中未能检出。HPT序列经与已知的致敏原数据库进行比较未见同源性,但在体外消化稳定性实验中,HPT蛋白在模拟的胃肠液环境中均迅速降解。结论就目前的检测水平来看,转sck基因大米中所含的HPT蛋白水平极低,且对消化环境不稳定,推测该标记基因表达蛋白不易引起可观察到的食用安全性问题。但利用表达的HPT蛋白直接进行动物急性毒性及致敏性实验的工作仍有待进行,有关的结果将进一步报道。     

转基因水稻中标记基因hpt表达行为的研究

目的探讨转sck基因水稻中标记基因hpt的表达行为。方法对经潮霉素抗性筛选的转基因水稻4个生长发育时期、不同组织的hpt基因进行PCR检测;提取4个生长发育时期PCR检测阳性植株的叶片总RNA,以hpt基因片断为探针进行Northernblot分析,并对不同生长时期的叶片和成熟期的茎部、根部、种子进行双夹心ELISA检测,以同种非转基因水稻M86相应时期的相应部位作阴性对照。结果转基因水稻不同生长时期、不同组织中均能扩出特异的hpt(832bp)片段;Northernblot结果显示,在4个生长发育时期的hpt基因在转录水平均有表达,但是表达水平较低,且不同生长发育时期之间无明显差别;ELISA检测结果显示HPT蛋白在4个生长时期的叶片和成熟期的茎部和根部均有表达,种子中HPT蛋白的含量不超过负对照,不能被检测。结论不同生长发育时期的叶片中hpt基因在转录水平和翻译水平表达均能稳定表达。成熟的种子中不含有可检测水平的HPT蛋白。