Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 75
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Biosens Bioelectron ; 154: 112071, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32056965

RESUMO

In the neuroendocrine system, corticotropin-releasing hormone (CRH) and adrenocorticotropic hormone (ACTH) play important roles in the regulation of the hypothalamic-pituitary-adrenal (HPA) system. Disorders of the HPA system lead to physiological problems, such as Addison's disease and Cushing's syndrome. Therefore, detection of CRH and ACTH is essential for diagnosing disorders related to the HPA system. Herein, receptors of the HPA axis were used to construct a bioelectronic sensor system for the detection of CRH and ACTH. The CRH receptor, corticotropin-releasing hormone receptor 1 (CRHR1), and the ACTH receptor, melanocortin 2 receptor (MC2R), were produced using an Escherichia coli expression system, and were reconstituted using nanodisc (ND) technology. The receptor-embedded NDs were immobilized on a floating electrode of a carbon nanotube field-effect transistor (CNT-FET). The constructed sensors sensitively detected CRH and ACTH to a concentration of 1 fM with high selectivity in real time. Furthermore, the reliable detection of CRH and ACTH in human plasma by the developed sensors demonstrated their potential in clinical and practical applications. These results indicate that CRHR1 and MC2R-based bioelectronic sensors can be applied for rapid and efficient detection of CRH and ACTH.


Assuntos
Hormônio Adrenocorticotrópico/isolamento & purificação , Técnicas Biossensoriais , Hormônio Liberador da Corticotropina/isolamento & purificação , Sistema Hipotálamo-Hipofisário/metabolismo , Doença de Addison/diagnóstico , Doença de Addison/genética , Hormônio Adrenocorticotrópico/química , Hormônio Liberador da Corticotropina/química , Síndrome de Cushing/diagnóstico , Síndrome de Cushing/genética , Humanos , Hidrocortisona/química , Hidrocortisona/genética , Sistema Hipófise-Suprarrenal/metabolismo , Receptor Tipo 2 de Melanocortina/química , Receptor Tipo 2 de Melanocortina/genética , Receptores da Corticotropina/química , Receptores da Corticotropina/genética , Receptores de Hormônio Liberador da Corticotropina/química , Receptores de Hormônio Liberador da Corticotropina/genética
2.
Biosens Bioelectron ; 131: 171-177, 2019 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-30831419

RESUMO

An electrochemical impedimetric immunosensor was developed for the detection of the neuropeptide Corticotropin Releasing Hormone (CRH) based on the immobilization of half-antibody fragments on gold nanoparticles (AuNp). Then, the optimal conditions for the obtainment of AuNp through electroplating on a bare gold electrode were studied. The results showed that the obtainment of AuNp at a fixed potential of -0.2 V for 330 s, at 80 °C and 2·10-3 mol·L-1 of HAuCl4 generates an adequate nanostructured surface and is a highly reproducible method. Also, the optimal conditions for immobilizing the half-antibody on AuNp were studied. The interaction of the CRH with the recognition layer of the immobilized half-antibody on the nanostructured surface was carried out by incubation at 4 °C for 2 h. A dissolution of [Fe(CN)6]4-/[Fe(CN)6]3- as a redox probe was used to study the electrochemical responses of the nanostructured surface and the immobilization processes of the half-antibody and detection of CRH, using cyclic voltammetry and electrochemical impedance spectroscopy. An immunosensor was obtained for the specific detection of CRH, within a range of 10.0-80.0 µg mL-1, with a limit of detection of 2.7 µg mL-1 and a limit of quantification of 9.2 µg mL-1. Additionally, the association constant between the CRH and the immobilized half-antibody was calculated at 1.96·105 M-1.


Assuntos
Técnicas Biossensoriais , Hormônio Liberador da Corticotropina/isolamento & purificação , Espectroscopia Dielétrica , Fragmentos de Imunoglobulinas/química , Anticorpos/química , Anticorpos/imunologia , Anticorpos Imobilizados/química , Hormônio Liberador da Corticotropina/química , Hormônio Liberador da Corticotropina/imunologia , Técnicas Eletroquímicas , Humanos , Imunoensaio , Fragmentos de Imunoglobulinas/imunologia , Limite de Detecção , Nanopartículas Metálicas/química , Nanoestruturas
3.
Mol Psychiatry ; 22(5): 733-744, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-27595593

RESUMO

A long-standing paradigm posits that hypothalamic corticotropin-releasing hormone (CRH) regulates neuroendocrine functions such as adrenal glucocorticoid release, whereas extra-hypothalamic CRH has a key role in stressor-triggered behaviors. Here we report that hypothalamus-specific Crh knockout mice (Sim1CrhKO mice, created by crossing Crhflox with Sim1Cre mice) have absent Crh mRNA and peptide mainly in the paraventricular nucleus of the hypothalamus (PVH) but preserved Crh expression in other brain regions including amygdala and cerebral cortex. As expected, Sim1CrhKO mice exhibit adrenal atrophy as well as decreased basal, diurnal and stressor-stimulated plasma corticosterone secretion and basal plasma adrenocorticotropic hormone, but surprisingly, have a profound anxiolytic phenotype when evaluated using multiple stressors including open-field, elevated plus maze, holeboard, light-dark box and novel object recognition task. Restoring plasma corticosterone did not reverse the anxiolytic phenotype of Sim1CrhKO mice. Crh-Cre driver mice revealed that PVHCrh fibers project abundantly to cingulate cortex and the nucleus accumbens shell, and moderately to medial amygdala, locus coeruleus and solitary tract, consistent with the existence of PVHCrh-dependent behavioral pathways. Although previous, nonselective attenuation of CRH production or action, genetically in mice and pharmacologically in humans, respectively, has not produced the anticipated anxiolytic effects, our data show that targeted interference specifically with hypothalamic Crh expression results in anxiolysis. Our data identify neurons that express both Sim1 and Crh as a cellular entry point into the study of CRH-mediated, anxiety-like behaviors and their therapeutic attenuation.


Assuntos
Ansiedade/metabolismo , Hormônio Liberador da Corticotropina/deficiência , Hipotálamo/metabolismo , Hormônio Adrenocorticotrópico/metabolismo , Tonsila do Cerebelo/metabolismo , Animais , Corticosterona/sangue , Hormônio Liberador da Corticotropina/isolamento & purificação , Hormônio Liberador da Corticotropina/metabolismo , Feminino , Glucocorticoides/metabolismo , Sistema Hipotálamo-Hipofisário/metabolismo , Camundongos , Camundongos Endogâmicos ICR , Camundongos Mutantes , Neurônios/metabolismo , Hormônios Liberadores de Hormônios Hipofisários/metabolismo , Sistema Hipófise-Suprarrenal/metabolismo , RNA Mensageiro/metabolismo , Receptores de Hormônio Liberador da Corticotropina/genética , Receptores de Hormônio Liberador da Corticotropina/metabolismo , Receptores de Glucocorticoides/metabolismo
6.
Ann N Y Acad Sci ; 1040: 150-5, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15891019

RESUMO

Corticotropin-releasing hormone (CRH) was isolated from the brain of the European green frog, Rana esculenta, by combining HPLC purification with radioimmunoassay (RIA) detection. The amino acid sequence SEEPPISLDLTFHLLREVLEMARAEQIAQQAHSNRKLMDII was identical with the sequence of bullfrog (R. catesbeiana) CRH that was deduced from a cDNA encoding the CRH precursor. Synthetic frog CRH enhanced the release of thyroid-stimulating hormone (TSH) from dispersed bullfrog pituitary cells in a concentration-dependent manner. The TSH-releasing activity of a bullfrog hypothalamic extract was decreased by approximately 45% in the presence of the CRH receptor antagonist, alpha-helical CRH(9-41), suggesting that CRH is one of the main TSH-releasing factors present in the bullfrog hypothalamus.


Assuntos
Clonagem Molecular/métodos , Hormônio Liberador da Corticotropina/genética , Hormônio Liberador da Corticotropina/isolamento & purificação , Sequência de Aminoácidos , Animais , Hormônio Liberador da Corticotropina/fisiologia , Humanos , Dados de Sequência Molecular , Hipófise/fisiologia , Rana catesbeiana , Rana esculenta
7.
Peptides ; 23(4): 671-81, 2002 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11897386

RESUMO

The rapid post-feeding diuresis of Rhodnius prolixus is under neurohormonal control and involves the integrated activity of the crop, Malpighian tubules and hindgut. One of the factors which is involved in this rapid diuresis is serotonin, however a peptide(s) is also considered to be involved. In other insects, corticotropin releasing factor (CRF)-like and kinin-like, calcitonin-like peptides and CAP(2b) have been demonstrated to be diuretic factors/hormones. In the present study, serotonin and CRF-like peptides increased secretion rate and cAMP content of Rhodnius Malpighian tubules, while the kinin-like peptides tested did not increase secretion rate or cAMP content of the tubules. Extracts of the CNS were processed and several HPLC fractions revealed kinin-like immunoreactivity but these fractions did not increase secretion rate when tested on Malpighian tubules. However, these same fractions did possess activity when tested on the hindgut contraction assay. In addition, material eluting at higher acetonitrile concentrations from the HPLC increased secretion and cAMP content of Rhodnius Malpighian tubules. This material eluted at concentrations of acetonitrile consistent with the elution time of CRF-like peptide standards. Synergism was demonstrated using the pharmacological agent forskolin and serotonin, tested on the rate of secretion of Rhodnius Malpighian tubules, in agreement with data of Maddrell et al. As well, synergism could be demonstrated using mesothoracic ganglionic mass (MTGM) homogenates and serotonin at some concentrations of serotonin. However, combinations of CRF-like material and serotonin increased secretion additively, not synergistically. Kinin-like peptides, tested along with CRF-like material and serotonin, at low concentrations, did not increase secretion above that of those factors tested alone.


Assuntos
AMP Cíclico/metabolismo , Túbulos de Malpighi/metabolismo , Peptídeos/farmacologia , Rhodnius/metabolismo , Animais , Hormônio Liberador da Corticotropina/análogos & derivados , Hormônio Liberador da Corticotropina/isolamento & purificação , Hormônio Liberador da Corticotropina/metabolismo , Diurese , Relação Dose-Resposta a Droga , Cininas/química , Cininas/isolamento & purificação , Cininas/metabolismo , Túbulos de Malpighi/efeitos dos fármacos , Peptídeos/metabolismo , Rhodnius/química , Rhodnius/efeitos dos fármacos , Serotonina/farmacologia , Extratos de Tecidos/química
8.
J Biol Chem ; 276(34): 31528-34, 2001 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-11425856

RESUMO

The first extracellular domain (ECD-1) of the corticotropin releasing factor (CRF) type 1 receptor, (CRFR1), is important for binding of CRF ligands. A soluble protein, mNT-CRFR1, produced by COS M6 cells transfected with a cDNA encoding amino acids 1--119 of human CRFR1 and modified to include epitope tags, binds a CRF antagonist, astressin, in a radioreceptor assay using [(125)I-d-Tyr(0)]astressin. N-terminal sequencing of mNT-CRFR1 showed the absence of the first 23 amino acids of human CRFR1. This result suggests that the CRFR1 protein is processed to cleave a putative signal peptide corresponding to amino acids 1--23. A cDNA encoding amino acids 24--119 followed by a FLAG tag, was expressed as a thioredoxin fusion protein in Escherichia coli. Following thrombin cleavage, the purified protein (bNT-CRFR1) binds astressin and the agonist urocortin with high affinity. Reduced, alkylated bNT-CRFR1 does not bind [(125)I-D-Tyr(0)]astressin. Mass spectrometric analysis of photoaffinity labeled bNT-CRFR1 yielded a 1:1 complex with ligand. Analysis of the disulfide arrangement of bNT-CRFR1 revealed bonds between Cys(30) and Cys(54), Cys(44) and Cys(87), and Cys(68) and Cys(102). This arrangement is similar to that of the ECD-1 of the parathyroid hormone receptor (PTHR), suggesting a conserved structural motif in the N-terminal domain of this family of receptors.


Assuntos
Hormônio Liberador da Corticotropina/genética , Sequência de Aminoácidos , Animais , Células COS , Dicroísmo Circular , Hormônio Liberador da Corticotropina/química , Hormônio Liberador da Corticotropina/isolamento & purificação , DNA Complementar , Humanos , Dados de Sequência Molecular , Solubilidade
9.
Neurosci Lett ; 292(1): 45-8, 2000 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-10996446

RESUMO

The genomic organization of rat urocortin was determined using both cDNA and liver genomic DNA as templates for polymerase chain reactions. A single intron of 261 bp was found upstream to the ATG start codon, and the whole urocortin coding sequence was shown to be contained in a single exon. Relying on these results, oligonucleotide primers were designed, which can differentiate genomic DNA contamination from cDNA-derived signals in a reverse transcription-polymerase chain reaction. Tissue screening for urocortin expression revealed that the mid-brain is the major site of urocortin mRNA expression, and that other peripheral organs, including lymphoid tissues and peripheral blood lymphocytes, do not produce urocortin.


Assuntos
Hormônio Liberador da Corticotropina/genética , Hormônio Liberador da Corticotropina/isolamento & purificação , Éxons , Regulação da Expressão Gênica , Íntrons , Animais , Sequência de Bases , Hormônio Liberador da Corticotropina/biossíntese , Feminino , Tecido Linfoide/química , Masculino , Mesencéfalo/química , Dados de Sequência Molecular , Especificidade de Órgãos/genética , Reação em Cadeia da Polimerase , Ratos , Ratos Sprague-Dawley , Urocortinas
10.
Eur J Endocrinol ; 141(3): 290-6, 1999 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10474128

RESUMO

Fawn-Hooded (FH) rats show central and peripheral abnormalities in serotoninergic functions and have attracted attention as an animal model of some pathologies, including depression and hypertension. In addition, these rats show a reduced growth rate. As the hypothalamic-pituitary-adrenal (HPA) axis has been implicated in both depression and hypertension, and the hypothalamic-somatotrophic (HSM) axis has a major role in growth, these two endocrine axes were characterised in FH rats as compared with outbred Sprague-Dawley (SD) rats in basal conditions. FH rats showed normal serum ACTH and corticosterone concentrations, but reduced serum corticosterone binding capacity. At a central level, normal expression of mRNA for glucocorticoid type II receptors in the hippocampal formation and mRNA for corticotrophin-releasing factor (CRF) in the paraventricular nucleus of the hypothalamus were observed in FH rats, whereas expression of mRNA for CRF in the central nucleus of the amygdala was enhanced compared with the expression in SD rats. Serum GH concentrations were normal in FH rats, IGF-I tended to be lower, and mRNA for somatostatin (SRIF) in the periventricular nucleus of the hypothalamus was significantly lower in FH rats than in SD rats. The reduced SRIF gene expression in rats with normal or slightly reduced GH and IGF-I, respectively, might be secondary to a defective central and peripheral response to IGF-I, compatible with the reduced growth of FH rats. The present results suggest that FH rats have abnormalities in both HPA and HSM axes that might be related to some of their physiopathological characteristics.


Assuntos
Encéfalo/fisiopatologia , Regulação da Expressão Gênica , Sistema Hipotálamo-Hipofisário/fisiopatologia , Sistema Hipófise-Suprarrenal/fisiopatologia , Serotonina/fisiologia , Hormônio Adrenocorticotrópico/sangue , Animais , Corticosterona/sangue , Hormônio Liberador da Corticotropina/isolamento & purificação , Sondas de DNA/química , Modelos Animais de Doenças , Hormônio do Crescimento/sangue , Hormônio do Crescimento/isolamento & purificação , Ensaio Imunorradiométrico/veterinária , Hibridização In Situ/veterinária , Fator de Crescimento Insulin-Like I/análise , Masculino , Radioimunoensaio/veterinária , Ratos , Ratos Sprague-Dawley , Receptores de Glucocorticoides/isolamento & purificação , Transcortina/fisiologia
11.
Genomics ; 50(1): 23-33, 1998 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-9628819

RESUMO

The mouse and human urocortin genes (Ucn and UCN, respectively) have been isolated, characterized, and found to have very similar structures. Each has two exons, and the entire coding region is located in the second exon, as is the case for the gene of the related peptide, corticotropin-releasing factor. Several putative transcription factor-binding sites were identified in each of the urocortin promoters, including a TATA box, a cyclic AMP response element (CRE), GATA-binding sites, and a C/EBP-binding site as well as a Brn-2-binding site(s). Sequence analyses of the mouse and human genes also revealed the presence of a previously identified gene, Mpv17, in the 5' region upstream of the urocortin gene. Functional studies following transient transfection of urocortin reporter plasmids in PC12 cells revealed that the urocortin promoter is controlled by both positive and negative elements; the CRE is important for basal activity as well as responsiveness to forskolin stimulation.


Assuntos
Hormônio Liberador da Corticotropina/química , Hormônio Liberador da Corticotropina/genética , Proteínas de Membrana , Alelos , Sequência de Aminoácidos , Animais , Sequência de Bases , Colforsina/farmacologia , Hormônio Liberador da Corticotropina/isolamento & purificação , DNA Complementar/química , Éxons , Humanos , Íntrons , Camundongos , Dados de Sequência Molecular , Regiões Promotoras Genéticas/efeitos dos fármacos , Proteínas/genética , Ratos , Transfecção/genética , Urocortinas
12.
Peptides ; 19(4): 643-7, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9622018

RESUMO

Regional distribution of urocortin-like immunoreactivity (UCN-LI) in the human brain was studied by radioimmunoassay and was compared with that of corticotropin-releasing hormone (CRH). In addition, the expression of UCN mRNA was examined by reverse transcriptase-polymerase chain reaction (RT-PCR) method. UCN-LI was detected in every region of brain examined, including hypothalamus, pons, cerebral cortex, and cerebellum. The concentrations of UCN-LI in the human brain were approximately 3 pmol/g wet weight in any brain region, and no marked regional difference was noted. On the other hand, the highest concentrations of CRH-LI were found in the frontal cortex, temporal cortex, and hypothalamus and the lowest in the pons. Reverse phase high-performance liquid chromatography of the UCN-LI in the human brain extract showed two immunoreactive peaks; one peak eluting earlier and one in the position of synthetic human UCN. RT-PCR showed that UCN mRNA was expressed in every region of brain examined. These findings indicated that UCN and UCN mRNA were widely expressed in the human brain.


Assuntos
Química Encefálica , Hormônio Liberador da Corticotropina/isolamento & purificação , RNA Mensageiro/isolamento & purificação , Adulto , Idoso , Hormônio Liberador da Corticotropina/genética , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Radioimunoensaio , Distribuição Tecidual , Urocortinas
13.
Proc Natl Acad Sci U S A ; 95(6): 3281-6, 1998 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-9501254

RESUMO

Evidence exists for the localization of the newly identified estrogen receptor beta (ERbeta) within the rat paraventricular nucleus (PVN) and supraoptic nucleus (SON), regions which lack ERalpha. Presently, we investigate whether ERbeta-like-immunoreactivity (-ir) is found within cells of several major neuropeptide systems of these regions. Young adult Sprague-Dawley rats were ovariectomized (OVX), and 1 week later half of the animals received estradiol-17beta (E). Dual-label immunocytochemistry was performed on adjacent sections by using an ERbeta antibody, followed by an antibody to either oxytocin (OT), arginine-vasopressin (AVP), or corticotropin releasing hormone. Nuclear ERbeta-ir was identified within SON and retrochiasmatic SON, and in specific PVN subnuclei: medial parvicellular part, ventral and dorsal zones, dorsal and lateral parvicellular parts, and in the posterior magnocellular part, medial and lateral zones. However, the ERbeta-ir within magnocellular areas was noticeably less intense. OT-/ERbeta-ir colocalization was confirmed in neurons of the parvicellular subnuclei, in both OVX and OVX+E brains ( approximately 50% of OT and 25% of ERbeta-labeled cells between bregma -1.78 and -2.00). In contrast, few PVN parvicellular neurons contained both AVP- and ERbeta-ir. As well, very little overlap was observed in the distribution of cells containing corticotropin releasing hormone- or ERbeta-ir. In the SON, most nuclear ERbeta-ir colocalized with AVP-ir, whereas few OT-/ERbeta-ir dual-labeled cells were observed. These findings suggest that estrogen can directly modulate specific OT and AVP systems through an ERbeta-mediated mechanism, in a tissue-specific manner.


Assuntos
Arginina Vasopressina/isolamento & purificação , Hormônio Liberador da Corticotropina/isolamento & purificação , Hipotálamo Anterior/química , Ocitocina/isolamento & purificação , Receptores de Estrogênio/isolamento & purificação , Animais , Receptor beta de Estrogênio , Feminino , Hipotálamo Anterior/citologia , Imuno-Histoquímica , Neurônios/química , Núcleo Hipotalâmico Paraventricular/química , Núcleo Hipotalâmico Paraventricular/citologia , Ratos , Ratos Sprague-Dawley , Núcleo Supraóptico/química , Núcleo Supraóptico/citologia , Distribuição Tecidual
14.
Jpn J Physiol ; 47(2): 147-59, 1997 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-9201544

RESUMO

Although CRH is the major contributor to the physiological regulation of ACTH secretion, it must be recognized that a considerable degree of heterogeneity exists regarding the chemistry and biological activity of various CRF-active substances, some of which still remain to be fully clarified. The widespread extrahypothalamic sources and diverse extrapituitary actions of CRFs suggest that multiple CRF components must act in concert for the organism to cope with the environmental changes and stresses.


Assuntos
Hormônio Liberador da Corticotropina/fisiologia , Hipotálamo/metabolismo , Placenta/metabolismo , Hormônio Adrenocorticotrópico/metabolismo , Sequência de Aminoácidos , Animais , Proteínas de Transporte/metabolismo , Cromatografia em Gel , Hormônio Liberador da Corticotropina/sangue , Hormônio Liberador da Corticotropina/química , Hormônio Liberador da Corticotropina/isolamento & purificação , Feminino , Humanos , Dados de Sequência Molecular , Gravidez , Homologia de Sequência de Aminoácidos , Estresse Fisiológico/metabolismo
15.
Biochemistry ; 36(49): 15538-45, 1997 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-9398282

RESUMO

The ovine corticotropin-releasing factor (CRF), a peptide hormone of 41 residues stimulating the secretion of adrenocorticotropic hormone, was thermodynamically investigated. By means of size exclusion chromatography and/or ultrafiltration, the CRF solution could be separated into random coil monomers and highly alpha-helical tetramers, which seem to have amphipathic helix bundle structure. Circular dichroism measurements along with diluting or concentrating the CRF solution revealed that there exists the micelle state above the concentration of 0.1 mM, which would be the critical micelle concentration (cmc). The micelle state was also proved by binding ability for 8-anilino-1-naphthalenesulfonate and endothermic change by dilution across the cmc. The tetramer showed the cooperative thermal transition at about 55 degrees C in the buffer solution (pH 7.5), so that it would have native-protein-like folding. On the other hand, the micelle undergoes gradual change to dissociated state by heating, regardless of the similar alpha-helicity to the tetramer. Above the cmc the equilibrium between the tetramer and the micelle takes place as well as that between the monomer and the micelle. Whereas, the direct conversion between the tetramer and the monomer scarcely occurred below the cmc. The titration experiment with 2,2,2-trifluoroethanol (TFE) revealed that the cmc decreases with increasing the concentration of TFE. This tendency is the same as that of general surfactants. Most of experimental results can be well explained by this three-phase model involving the monomer, the tetramer, and the micelle. The lack of the equilibrium between the monomer and the tetramer indicates that the folding pathway of the tetramer is the transformation only through the micelle state and not from the monomer. This pathway resembles the collapse model among the phenomenological models for thermodynamic protein folding. By the mathematical consideration for the dissociation of micelle, we have demonstrated that the expected content of undegradable k-mer is 2/(k + 1), which agreed well with the observed tetramer content of CRF (40%).


Assuntos
Hormônio Liberador da Corticotropina/química , Micelas , Dobramento de Proteína , Naftalenossulfonato de Anilina , Animais , Biopolímeros , Varredura Diferencial de Calorimetria , Cromatografia em Gel , Dicroísmo Circular , Hormônio Liberador da Corticotropina/isolamento & purificação , Ovinos
16.
Proc Natl Acad Sci U S A ; 92(26): 12323-7, 1995 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-8618894

RESUMO

A diuretic hormone of unusual structure was isolated from extracts of whole heads of the mealworm Tenebrio molitor. The hormone is a 37-aa peptide of 4371 Da, with the sequence SPTISITAPIDVLRKTWEQERARKQMVKNREFLNSLN. This peptide increases cAMP production in Malpighian tubules of T. molitor. The amino acid sequence reveals that this peptide is a member of the family of sauvagine/corticotropin-releasing factor/urotensin I-related insect diuretic hormones. The C-terminal sequence of this peptide is quite different from other members of this family, which have a hydrophobic C terminus (isoleucinamide or valinamide). When aligned comparably, T. molitor diuretic hormone has a more hydrophilic C terminus, leucylasparagine (free acid). In contrast to all other known diuretic hormones of this family, this peptide has exceptionally low stimulatory activity on cAMP production in Malpighian tubules of Manduca sexta. However, at nanomolar concentrations it stimulates cAMP production in Malpighian tubules of T. molitor. Diuretic hormones of this family have been isolated previously from Lepidoptera, Orthoptera, Dictyoptera, and Diptera. This appears to be the first diuretic hormone isolated from a coleopteran insect.


Assuntos
Hormônio Liberador da Corticotropina/química , Hormônio Liberador da Corticotropina/isolamento & purificação , Hormônios de Inseto/química , Hormônios de Inseto/isolamento & purificação , Tenebrio/fisiologia , Sequência de Aminoácidos , Aminoácidos/análise , Animais , Hormônio Liberador da Corticotropina/farmacologia , AMP Cíclico/metabolismo , Diurese , Relação Dose-Resposta a Droga , Humanos , Hormônios de Inseto/farmacologia , Túbulos de Malpighi/efeitos dos fármacos , Túbulos de Malpighi/fisiologia , Dados de Sequência Molecular , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/isolamento & purificação , Ratos , Homologia de Sequência de Aminoácidos
18.
Acta Endocrinol (Copenh) ; 128(6): 503-7, 1993 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8393256

RESUMO

Plasma levels of corticotropin-releasing hormone (CRH) were measured in hypothalamic-pituitary-adrenal disorders and chronic renal failure to investigate the clinical significance of plasma CRH. The mean plasma CRH level in normal subjects (N = 26) was 1.64 +/- 0.43 pmol/l (normal range 0.77-2.5 pmol/l). Four of six patients with hypothalamic disorders receiving hydrocortisone supplementation had a low plasma CRH level. Two of six patients with Sheehan's syndrome had a low plasma CRH level whereas one patient had a high plasma CRH level. Two patients with Cushing's syndrome had a low plasma CRH level whereas two patients with Cushing's disease had a normal plasma CRH level. Six of 19 patients receiving prednisolone therapy had a low plasma CRH level. The mean plasma CRH level in this group was 0.97 +/- 0.34 pmol/l, which is significantly lower than that in the normal group. In this group, significant correlation was seen between plasma CRH and adrenocorticotropin levels. Eleven of 21 patients with chronic renal failure undergoing hemodialysis had a high plasma CRH level. Just after hemodialysis the plasma CRH levels decreased in 15 of 20 patients, while plasma adrenocorticotropin and cortisol levels increased in 13 of 19 patients and in 15 of 20 patients, respectively. Immunoreactive CRH in plasma measured both before and after hemodialysis eluted similarly on reversed-phase high-performance liquid chromatography. These results suggest that the plasma CRH level is at least partially suppressed by a chronically elevated plasma glucocorticoid level and that CRH in plasma is partially removed by hemodialysis.


Assuntos
Doenças das Glândulas Suprarrenais/sangue , Hormônio Liberador da Corticotropina/sangue , Doenças Hipotalâmicas/sangue , Falência Renal Crônica/sangue , Doenças da Hipófise/sangue , Doenças das Glândulas Suprarrenais/tratamento farmacológico , Hormônio Adrenocorticotrópico/sangue , Cromatografia Líquida de Alta Pressão , Hormônio Liberador da Corticotropina/isolamento & purificação , Humanos , Hidrocortisona/sangue , Hidrocortisona/uso terapêutico , Doenças Hipotalâmicas/tratamento farmacológico , Falência Renal Crônica/terapia , Doenças da Hipófise/tratamento farmacológico , Prednisolona/uso terapêutico , Diálise Renal
19.
Peptides ; 13(3): 451-60, 1992.
Artigo em Inglês | MEDLINE | ID: mdl-1381826

RESUMO

The central nucleus of the amygdala, bed nucleus of the stria terminalis, and central gray are important components of the neural circuitry responsible for autonomic and behavioral responses to threatening or stressful stimuli. Neurons of the amygdala and bed nucleus of the stria terminalis that project to the midbrain central gray were tested for the presence of peptide immunoreactivity. To accomplish this aim, a combined immunohistochemical and retrograde tracing technique was used. Maximal retrograde labeling was observed in the amygdala and bed nucleus of the stria terminalis after injections of retrograde tracer into the caudal ventrolateral midbrain central gray. The majority of the retrogradely labeled neurons in the amygdala were located in the medial central nucleus, although many neurons were also observed in the lateral subdivision of the central nucleus. Most of the retrogradely labeled neurons in the BST were located in the ventral and posterior lateral subdivisions, although cells were also observed in most other subdivisions. Retrogradely labeled neurotensin, corticotropin releasing factor (CRF), and somatostatin neurons were mainly observed in the lateral central nucleus and the dorsal lateral BST. Retrogradely labeled substance P-immunoreactive cells were found in the medial central nucleus and the posterior and ventral lateral BST. Enkephalin-immunoreactive retrogradely labeled cells were not observed in the amygdala or bed nucleus of the stria terminalis. A few cells in the hypothalamus (paraventricular and lateral hypothalamic nuclei) that project to the central gray also contained CRF and neurotensin immunoreactivity. The results suggest the amygdala and the bed nucleus of the stria terminalis are a major forebrain source of CRF, neurotensin, somatostatin, and substance P terminals in the midbrain central gray.


Assuntos
Tonsila do Cerebelo/anatomia & histologia , Substância Cinzenta Periaquedutal/anatomia & histologia , Prosencéfalo/anatomia & histologia , Tálamo/anatomia & histologia , Animais , Hormônio Liberador da Corticotropina/isolamento & purificação , Encefalinas/isolamento & purificação , Imunofluorescência , Imuno-Histoquímica/métodos , Masculino , Neurônios/química , Neuropeptídeos/isolamento & purificação , Neurotensina/isolamento & purificação , Ratos , Somatostatina/isolamento & purificação , Substância P/isolamento & purificação
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...