Quantification of VGF- and pro-SAAS-derived peptides in endocrine tissues and the brain, and their regulation by diet and cold stress

Two novel granin-like polypeptides, VGF and pro-SAAS, which are stored in and released from secretory vesicles and are expressed widely in nervous, endocrine, and neuroendocrine tissues, play roles in the regulation of body weight, feeding, and energy expenditure. Both VGF and pro-SAAS are cleaved into peptide fragments, several of which are biologically active. We utilized a highly sensitive and specific radioimmunoassay (RIA) to immunoreactive, pro-SAAS-derived PEN peptides, developed another against immunoreactive, VGF-derived AQEE30 peptides, and quantified these peptides in various mouse tissues and brain regions. Immunoreactive AQEE30 was most abundant in the pituitary, while brain levels were highest in hypothalamus, striatum, and frontal cortex. Immunoreactive PEN levels were highest in the pancreas and spinal cord, and in brain, PEN was most abundant in striatum, hippocampus, pons and medulla, and cortex. Since both peptides were expressed in hypothalamus, a region of the brain that controls feeding and energy expenditure, double label immunofluorescence studies were employed. These demonstrated that 42% of hypothalamic arcuate neurons coexpress VGF and SAAS peptides, and that the intracellular distributions of these peptides in arcuate neurons differed. By RIA, cold stress increased immunoreactive AQEE30 and PEN peptide levels in female but not male hypothalamus, while a high fat diet increased AQEE30 and PEN peptide levels in female but not male hippocampus. VGF and SAAS-derived peptides are therefore widely expressed in endocrine, neuroendocrine, and neural tissues, can be accurately quantified by RIA, and are differentially regulated in the brain by diet and cold stress.     

Relationship between plasma leptin-like protein levels, begging and provisioning in nestling thin-billed prions Pachyptila belcheri

While there have been many studies in various species examining the physiological role of leptin, there are so far no data in free-living seabirds. In the present study, we assess whether leptin is expressed in thin-billed prions (Pachyptila belcheri) and we investigate its relationship with feeding-related parameters including body condition, begging intensities and provisioning rates. We showed by Western Blot analysis using leptin-specific antibody that leptin-like protein (14-16 kDa) is expressed in adipose tissue and liver of nestling thin-billed prions. Plasma leptin-like protein levels, determined by RIA, were in the same range (1-3 ng/ml) as in other avian species and increased with age. In two breeding seasons, the plasma leptin-like protein levels were negatively correlated with provisioning rates (R = −0.67 and −0.35 in 2003 and 2004, respectively, P < 0.05) indicating that endogenous leptin may be an anorexigenic hormone in wild birds. Plasma leptin-like protein levels were positively correlated with begging intensities (R = 0.43 and 0.37 in 2003 and 2004, respectively, P < 0.05), and this may be because hungry nestling seabird chicks with low body conditions increased their begging intensities. Plasma leptin-like protein levels did not correlate either with plasma triglyceride or glucose levels in thin-billed prions. Overall, these findings show the presence of leptin-like protein in free-living seabirds and provide new insights into its function and its possible role in feeding-associated behaviours.     

Corticotropin-releasing factor test in melancholic patients in depressed state versus recovery: a comparative study

PURPOSE: Basal adrenocorticotropin hormone (ACTH) and cortisol levels and their response to corticotropin-releasing factor (CRF) test were studied in melancholic depressive patients in depressed state and recovery, and compared with healthy controls. METHODS: Fifty-four outpatients diagnosed with unipolar depressive disorder with melancholic features according to DSM-IV and 23 healthy controls were included in the study. The Structured Clinical Interview for DSM-IV (SCID-IV) was used for diagnosis. Twenty-nine patients were in recovery, while 25 were in depressed state at the moment of the administration of the CRF test. FINDINGS: No differences were found between the recovered and depressed groups with respect to CRF test. Lower ACTH and higher cortisol levels with significant differences were shown in the neuroendocrine variables at 15, 30, and 60 min, and in peak response and increase, in the ACTH and cortisol response curves to CRF challenge between the groups of melancholic patients, both recovered and depressed, compared with the healthy control subjects. Moreover, recovered and depressed melancholic patients had a higher whole cortisol area under the curve with significant differences than the healthy control subjects. CONCLUSIONS: The crossover clinical status at the moment of the CRF test doesn't differentiate changes in the HPA axis in melancholic patients, while we did find significant differences in the group of healthy controls in comparison with the groups of melancholic patients both in depressive state and recovery. This supports the hypothesis that hypothalamic pituitary adrenal (HPA) axis shows alterations that remain in depressive patients even after recovery.     

Production, secretion, and biological activity of the C-terminal flanking peptide of human progastrin

BACKGROUND & AIMS: Processing of progastrin, the 80-amino acid precursor of the hormone gastrin, generates a variety of peptides with distinct distributions and biological activities. However, little is known regarding the expression, secretion, and biological activity of the 6-amino acid C-terminal flanking peptide (CTFP) of progastrin. The objectives were to determine the concentration of CTFP in normal subjects and patients with gastrointestinal diseases and to investigate the biological activity of CTFP. METHODS: CTFP, gastrin-amide (Gamide), glycine-extended gastrin (Ggly), and progastrin were measured using region-specific radioimmunoassay (RIA) in antral extracts and resected colorectal cancers (CRC) and in plasma from normal subjects (fasting and meal stimulated) and from patients with CRC, multiple endocrine neoplasia type 1 (MEN-1), or pernicious anemia. The effect of CTFP on proliferation, migration, and activation of the mitogen-activated protein kinase (MAPK) pathway in several types of gastrointestinal cell lines was determined. RESULTS: CTFP is by far the predominant progastrin-derived peptide found in the antrum (4-fold higher than Gamide), resected CRC, and circulation (60-fold higher than Gamide) and is released after meal stimulation. The hypergastrinemic patients (MEN-1, pernicious anemia) had elevated plasma Gamide but unaltered CTFP demonstrating differential secretion of these 2 progastrin-derived peptides. Finally, CTFP stimulated proliferation and migration and activated MAPK of cells in culture. CONCLUSIONS: The high and regulated expression of CTFP in healthy and diseased subjects combined with the evidence for biological activity of CTFP demonstrates that CTFP is not an inactive metabolite of progastrin processing but is a bioactive peptide with potential roles in the normal and diseased gastrointestinal tract.     

Postnatal development in vasopressin deficient Brattleboro rats with special attention to the hypothalamo-pituitary–adrenal axis function: the role of maternal genotype

Anomalies in hormonal and neurotransmitter status during perinatal period can lead to lifespan alterations in the central nervous system. Vasopressin is present early in the brain and has various mitogenic, metabolic and physiological actions, e.g. in water homeostasis or in the regulation of the hypothalamo-pituitary–adrenal (HPA) axis. Therefore we examine the possible role of vasopressin in perinatal development with special attention to the influence of maternal genotype and to the HPA axis regulation. We compared homozygous vasopressin deficient (di/di) Brattleboro rats to their heterozygous (di/+) littermates both from di/+ and di/di mother. Higher locomotion due to reduced adaptation was present at preweaning. During the first 10 days of life the di/di pups from di/di mother were the smallest, while in the later perinatal period the genotype of the pups became the more important determinant of the somatic development, namely the di/di pups from both mothers had reduced weight gain. Generally the lack of vasopressin in the pups fastened the somatic development (pinna detachment, eye and ear opening, incisor eruption) however the neurobehavioral development (palmar grasp reflex, righting reflex, negative geotaxis, etc.) was not influenced profoundly by either the mother's or the pup's genotype. The lack of vasopressin in pups abolished the 24 h maternal separation induced adrenocorticotrop hormone (ACTH) elevation while the accompanying corticosterone rises were even higher. The vasopressin deficiency of the mother reduced the resting ACTH and all corticosterone levels in all pups. So we can conclude that the lack of vasopressin speeds up the development, probably there is a greater drive for self-sufficiency in these animals. The mother's vasopressin deficiency reduced the HPA axis reactivity of the pups. The role of vasopressin in the HPA axis regulation is important during the perinatal period independently from the mother's genotype. The large discrepancy between ACTH and corticosterone regulation requires further studies.     

电针对大鼠全脑组织中cAMP和cGMP含量的影响

①目的 探讨针刺镇痛与全脑cAMP和cGMP含量变化之间的关系。②方法 运用放射免疫分析法（RIA）测定大鼠电针前后，全脑组织中cAMP和cGMP含量的变化。③结果 电针30min提高大鼠痛阈的同时，使全脑cAMP含量显降低（P＜0．05）。④结论 中枢环核苷酸可能参与针刺镇痛。     

鼻咽癌患者外周血TGF-α和TGF-β1水平的临床意义

目的 本研究对不同分化以及病期等不同类型的鼻咽癌患者外周血TGF-α和TGF-β1的含量及其放疗前后变化进行分析，并探讨其临床意义。方法 采用酶联免疫吸附实验方法对52例明确诊断的鼻咽癌患者放疗前后以及10名健康献血员外周血TGF-β1水平进行测定，并分别对其水平的改变与鼻咽癌的辅助诊断、分化程度、临床分期、近期疗效、年龄、性别进行对比分析。结果 鼻咽癌患者血清TGF-α和TGF-β1水平均明显高于正常人。放疗后血清TGF-α和TGF-β1水平均较放疗前明显降低，且肿瘤分化程度低的患者明显高于分化程度高者，随着临床分期级别的升高，水平也逐渐升高。患者外周血TGF-α和TGF-β1水平与年龄和性别无关。结论 鼻咽癌患者外周血清TGF-α和TGF-β1水平的测定可以为临床诊断提供依据，并能监测鼻咽癌放疗疗效和预后。     

电化学发光免疫法与放射免疫法测定血清铁蛋白的评价

目的:评价电化学发光免疫分析法(ECLIA)和放射免疫分析法(RIA)在测定血清铁蛋白(SF)中的应用。方法:用ECLIA、RIA分别对中浓度SF的标本进行回收试验和抗干扰试验(干扰物为血红蛋白),对低、高浓度SF的标本进行重复试验。结果:平均回收率ECLIA为95.6%、RIA为93.5%,两种方法比较,差异无显著性(P>0.05);变异系数(CV)ECLIA为3.0%、4.3%,RIA为8.5%、9.3%,两种方法比较,差异均有显著性(P<0.05);抗血红蛋白(Hb)干扰能力,当血清中Hb浓度在1.0g/L~6.0g/L时,随Hb含量的增加,两种方法测定SF时的干扰都逐渐增加(正干扰),血清中Hb浓度≥4.0g/L用ECLIA测定SF和血清中Hb浓度>2.0g/L用RIA测定SF时,其结果的偏差系数(CB)都>5.0%。结论:两种方法测定SF准确性、精密度均符合要求,且ECLIA优于RIA;标本严重溶血时,两种方法的测定结果均偏高。