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1.
Thyrotropin-releasing hormone precursor: characterization in rat brain 总被引：14，自引：0，他引：14
R M Lechan P Wu I M Jackson H Wolf S Cooperman G Mandel R H Goodman 《Science (New York, N.Y.)》1986,231(4734):159-161
To characterize the precursor of mammalian thyrotropin-releasing hormone (TRH), a rat hypothalamic lambda gt11 library was screened with an antiserum directed against a synthetic peptide representing a portion of the rat TRH prohormone. The nucleotide sequence of the immunopositive complementary DNA encoded a protein with a molecular weight of 29,247. This protein contained five copies of the sequence Gln-His-Pro-Gly flanked by paired basic amino acids and could therefore generate five TRH molecules. In addition, potential cleavage sites in the TRH precursor could produce other non-TRH peptides, which may be secreted. In situ hybridization to rat brain sections demonstrated that the pre-proTRH complementary DNA detected neurons concentrated in the parvocellular division of the paraventricular nucleus, the same location as cells detected by immunohistochemistry. These findings indicate that mammalian TRH arises by posttranslational processing of a larger precursor protein. The ability of the TRH prohormone to generate multiple copies of the bioactive peptide may be an important mechanism in the amplification of hormone production. 相似文献
2.
Immunohistochemical localization in the rat brain of the precursor for thyrotropin-releasing hormone 总被引：1，自引：0，他引：1
A rabbit antiserum to a peptide sequence present in the precursor for thyrotropin-releasing hormone (proTRH), deduced from cloned amphibian-skin complementary DNA, was raised by immunization with the synthetic decapeptide Cys-Lys-Arg-Gln-His-Pro-Gly-Lys-Arg-Cys (proTRH-SH). Immunohistochemical studies on rat brain tissue showed staining of neuronal perikarya in the parvicellular division of the paraventricular nucleus of the hypothalamus and the raphe complex of the medulla, identical to that already described for thyrotropin-releasing hormone (TRH). Immunostaining was abolished by preincubation with proTRH-SH (10(-6)M) but not TRH (10(-5)M). Both TRH precursor and TRH were located in neurons of the paraventricular nucleus. However, in contrast to the findings for TRH, no staining was observed in axon terminals of the median eminence. These results suggest that a TRH precursor analogous to that reported in frog skin is present in the rat brain and that TRH in the mammalian central nervous system is a product of ribosomal biosynthesis. 相似文献
3.
Thyrotropin-releasing hormone in specific nuclei of rat brain 总被引：18，自引：0，他引：18
M J Brownstein M Palkovits J M Saavedra R M Bassiri R D Utiger 《Science (New York, N.Y.)》1974,185(147):267-269
The regional distribution of thyrotropin-releasing hormone (TRH) in rat brain was studied. The greatest concentration of TRH was found in the median eminence. High concentrations were also found in several hypothalamic nuclei. Outside the hypothalamus, relatively large amounts of TRH were found in the septal and preoptic areas. 相似文献
4.
Effects of cold stress on hypothalamic corticotrophin-releasing and thyrotropin-releasing hormone messenger RNA levels in chickens 总被引：1，自引：0，他引：1
WANG Jintao and XU Shiwen* College of Veterinary Medicine Northeast Agricultural University Harbin China Animal Science Veterinary Medicine Research Institute Heilongjiang Academy of Nongken Sciences Harbin China 《东北农业大学学报(英文版)》2007,14(4):327-332
There is increasing evidence that stress can activate the hypothalamic-pituitary-adrenal-axis and hypothalamic-pituitary- thyroid-axis,and further affect the synthesis and secretion of corticotrophin-releasing hormone(CRH)and thyrotropin-releasing hormone(TRH).To evaluate the effect of cold stress on the hypothalamic CRH and TRH messenger RNA(mRNA)levels in Yisha chickens,male Yisha chickens were subjected to acute(1,6,12 h)and chronic(5,10,20 d)cold stress(12±1)℃.Hypothalami were collected for assessment of mRNA levels by semi-quantitative RT-PCR.Acute stress resulted in a significant decrease of CRH mRNA levels at 6 and 12 h,and a significant increase of TRH mRNA levels at every stress time point.Chronic cold stress resulted in a significant increase of CRH mRNA levels and a significant decrease of TRH mRNA levels compared with the control group at every stress time point.The results suggest that the two genes differently respond to cold stress at the mRNA levels.And the different degrees of cold stress will produce different effects on the identical gene. 相似文献
5.
Suprachiasmatic nucleus vasopressin messenger RNA: circadian variation in normal and Brattleboro rats 总被引：9，自引：0，他引：9
In situ hybridization of an oligonucleotide probe complementary to vasopressin messenger RNA (mRNA) in sections from normal or Brattleboro rat hypothalami revealed hybridization densities in each of three vasopressin-rich nuclei: the supraoptic, paraventricular, and suprachiasmatic. When entrained to a daily light-dark cycle, each rat strain displayed diurnal variation in hybridizable mRNA in the suprachiasmatic, but not in the supraoptic or paraventricular nuclei. The higher values for suprachiasmatic mRNA in the morning correlate well with previously elucidated morning increases in vasopressin immunoreactivity in the cerebrospinal fluid. These results support the utility of in situ hybridization techniques for elucidating physiological influences on regional peptidergic function, are consistent with a prominent role for vasopressinergic suprachiasmatic neurons in generating the cerebrospinal fluid vasopressin rhythm, and suggest that regulation of this mRNA rhythm is not dependent on release of intact peptide. 相似文献
6.
Thyrotropin-releasing hormone: regional distribution in rat brain 总被引：18，自引：0，他引：18
A sensitive and specific radioimmnunoassay has been used to measure the distribution of thyrotropin-releasing hormone (TRH) in rat brain. All areas of brain tested, except cerebellum, contained readily measurable amounts of TRH. The hypothalamus contained only 31.2 percent of the total brain content of TRH. These results support recent suggestions of central actions for TRH in addition to its hypophysiotropic functions. 相似文献
7.
Thyrotropin-releasing hormone induces rhythmic bursting in neurons of the nucleus tractus solitarius 总被引：4，自引：0，他引：4
The nucleus tractus solitarius (NTS) contains neurons that are part of the central neuronal network controlling rhythmic breathing movements in mammals. Nerve terminals within the NTS show immunoreactivity to thyrotropin-releasing hormone (TRH), a neuropeptide that has potent stimulatory effects on respiration. By means of a brainstem slice preparation in vitro, TRH induced rhythmic bursting in neurons in the respiratory division of the NTS. The frequency of bursting was voltage-dependent and could be reset by short depolarizing current pulses. In the presence of tetrodotoxin, TRH produced rhythmic oscillations in membrane potential whose frequency was also voltage-dependent. These observations suggest that TRH modulates the membrane excitability of NTS neurons and allows them to express endogenous bursting activity. 相似文献
8.
Biosynthesis of thyrotropin-releasing hormone (L-pyroglutamyl-L-histidyl-L-proline amide) in vitro was studied. Rat hypothalamic fragments were incubated in Krebs-Ringer bicarbonate buffer that contained either (14)C-labeled proline, histidine, or glutamic acid (the three probable precursor amino acids,) and for control purposes each of 16 other naturally occurring amino acids. A number of labeled peptides were synthesized. With the use of synthetic thyrotropin-releasing hormone, detected by the Pauly reagent or with (125)1-labeled thyrotropin-releasing hormone as a marker, thin-layer chromatograms, paper electrophoresis, and carboxymethyl cellulose ion exchange chromatography revealed that only proline, histidine, and glutamic acid were consistently incorporated into peptides associated with the thyrotropin-releasing hormone region. This synthesizing activity was found in stalk median eminence, ventral hypothalamus. and dorsal hypothalamus but not in neural lobe or cerebral cortex. Because the biosynthetic peptide has identical properties with L-pyroglutamyl-L-histidyl-L-proline amide, it is probable that rat thyrotropin-releasing hormone is similar or identical to both bovine and porcine thyrotropin-releasing hormone and that the native material is present in the pyroglutamyl form in tissues. 相似文献
9.
Thyroid hormone induction of an autocrine growth factor secreted by pituitary tumor cells 总被引：3，自引：0，他引：3
Thyroid hormones stimulate the rate of cell division by poorly understood mechanisms. The possibility that thyroid hormones increase cell growth by stimulating secretion of a growth factor was investigated. Thyroid hormones are nearly an absolute requirement for the division of GH4C1 rat pituitary tumor cells plated at low density. Conditioned media from cells grown with or without L-triiodothyronine (T3) were treated with an ion exchange resin to remove T3 and were tested for ability to stimulate the division of GH4C1 cells. Conditioned medium from T3-treated cells was as active as thyroid hormone at promoting GH4C1 cell growth but did not elicit other thyroid hormone responses, induction of growth hormone, and down-regulation of thyrotropin-releasing hormone receptors, as effectively as T3 did. A substance or substances associated with T3-induced growth stimulatory activity migrated at high molecular weight at neutral pH and was different from known growth-promoting hormones induced by T3. The results demonstrate that thyroid hormones stimulate the division of GH4C1 pituitary cells by stimulating the secretion of an autocrine growth factor. 相似文献
10.
Radioimmunoassayable prolactin rises in postpartum women during nursing and after intravenous thyrotropin-releasing hormone (TRH). Prolactin release induced by TRH can be dissociated from the postsuckling response. In addition to this, increases in endogenous prolactin secretion are followed by marked breast engorgement and milk letdown, especially after intravenous TRH. In this group of breast-feeding women, vaginal smears remained atrophic even up to 410 postpartum days. Prolactin appears to influence the production of breast milk, and the maintenance of a regular nursing pattern seems to promote the maintenance of ovarian unresponsiveness to circulating gonadotropins. 相似文献
11.
Paradoxical elevation of growth hormone by intraventricular somatostatin: possible ultrashort-loop feedback 总被引：8，自引：0，他引：8
Somatostatin, the growth hormone-inhibiting factor, when microinjected into the third ventricle of the rat brain, paradoxically induced the release of growth hormone. A pituitary site of action having been ruled out, this result supports the concept that exogenous somatostatin within the hypothalamus acts either to suppress the release of somatostatin from somatostatin-containing neurons, possibly via an ultrashort-loop feedback mechanism, or to augment release of hypothalamic growth hormone-releasing factor, thereby inducing a release of growth hormone. Injection of somatostatin into the third ventricle also decreased plasma concentrations of luteinizing hormone, follicle-stimulating hormone, and thyroid-stimulating hormone, probably by inhibiting the release of luteinizing hormone-releasing factor and thyrotropin-releasing factor. 相似文献
12.
13.
Amyloid protein precursor messenger RNAs: differential expression in Alzheimer's disease 总被引：25，自引：0，他引：25
M R Palmert T E Golde M L Cohen D M Kovacs R E Tanzi J F Gusella M F Usiak L H Younkin S G Younkin 《Science (New York, N.Y.)》1988,241(4869):1080-1084
In situ hybridization was used to assess total amyloid protein precursor (APP) messenger RNA and the subset of APP mRNA containing the Kunitz protease inhibitor (KPI) insert in 11 Alzheimer's disease (AD) and 7 control brains. In AD, a significant twofold increase was observed in total APP mRNA in nucleus basalis and locus ceruleus neurons but not in hippocampal subicular neurons, neurons of the basis pontis, or occipital cortical neurons. The increase in total APP mRNA in locus ceruleus and nucleus basalis neurons was due exclusively to an increase in APP mRNA lacking the KPI domain. These findings suggest that increased production of APP lacking the KPI domain in nucleus basalis and locus ceruleus neurons may play an important role in the deposition of cerebral amyloid that occurs in AD. 相似文献
14.
Thyrotropin-releasing hormone: evidence for thyroid response to intravenous injection in man 总被引：1，自引：0，他引：1
C S Hollander T Mitsuma L Shenkman P Woolf M C Gershengorn 《Science (New York, N.Y.)》1972,175(18):209-210
Administration of thyrotropin-releasing hormone to normal subjects causes a prompt rise in plasma thyrotropin concentration, followed by a significant increase in circulating plasma triiodothyronine. These observations may prove to be of value in simultaneously assessing the ability of the pituitary and thyroid glands to respond to their trophic hormones. 相似文献
15.
16.
Endothelin: a novel peptide in the posterior pituitary system 总被引：21，自引：0，他引：21
T Yoshizawa O Shinmi A Giaid M Yanagisawa S J Gibson S Kimura Y Uchiyama J M Polak T Masaki I Kanazawa 《Science (New York, N.Y.)》1990,247(4941):462-464
Endothelin (ET), originally characterized as a 21-residue vasoconstrictor peptide from endothelial cells, is present in the porcine spinal cord and may act as a neuropeptide. Endothelin-like immunoreactivity has now been demonstrated by immunohistochemistry in the paraventricular and supraoptic nuclear neurons and their terminals in the posterior pituitary of the pig and the rat. The presence of ET in the porcine hypothalamus was confirmed by reversed-phase high-pressure liquid chromatography and radioimmunoassay. Moreover, in situ hybridization demonstrated ET messenger RNA in porcine paraventricular nuclear neurons. Endothelin-like immunoreactive products in the posterior pituitary of the rat were depleted by water deprivation, suggesting a release of ET under physiological conditions. These findings indicate that ET is synthesized in the posterior pituitary system and may be involved in neurosecretory functions. 相似文献
17.
Arginine vasopressin as a thyrotropin-releasing hormone 总被引：4，自引：0，他引：4
Although hypothyroidism (with concomitant increased levels of thyroid-stimulating hormone) has been associated with elevated plasma vasopressin, the role that vasopressin plays in controlling thyroid-stimulating hormone secretion from the adenohypophysis is not understood. In two in vitro pituitary cell systems, vasopressin caused a specific and dose-related release of thyroid-stimulating hormone from cells that was equal in potency to that elicited by thyrotropin-releasing hormone, the primary acknowledged regulator of thyroid-stimulating hormone release. When injected into the hypothalamus, however, vasopressin specifically inhibited the release of thyroid-stimulating hormone. Thus, vasopressin may exert differential regulatory effects on thyroid-stimulating hormone secretion in the hypothalamus and pituitary gland. 相似文献
18.
建立去卵巢SD大鼠模型,运用原位组织杂交方法,通过补充不同剂量大豆异黄酮观察其对ERα、NGF、IL-2、AR mRNA在小脑中的表达和分布影响,探讨大豆异黄酮对小脑的作用机制和意义及其剂量关系。结果显示:ERα、NGF、IL-2、AR mRNA杂交信号主要分布于小脑皮质的蒲肯野氏细胞层和小脑室顶核、间位核和齿状核中,小脑皮质的分子层和颗粒层也有少量弱杂交信号表达;杂交信号主要定位于胞核,也存在于胞浆、胞膜和突起中,4种杂交信号变化的总趋势为去卵巢大鼠小脑皮质及小脑核中ERα、NGF、IL-2、AR mRNA的表达强度和阳性数目显著降低;而补充不同剂量大豆异黄酮后,4种物质的阳性杂交信号强度和数目均有不同程度回升,其中高剂量组基本恢复到假手术组水平,低剂量组仅有少许回升或无变化,中剂量组介于两者之间。从以上结果得出:大豆异黄酮可在基因水平上促进ERα、NGF、IL-2、AR在小脑中的表达,且存在剂量依赖性;这4种物质表达变化的相似性提示四者在大豆异黄酮对小脑的作用中是相互调节和影响的。 相似文献
19.
Expression of the beta-nerve growth factor gene in hippocampal neurons 总被引：16，自引：0，他引：16
C Ayer-LeLievre L Olson T Ebendal A Seiger H Persson 《Science (New York, N.Y.)》1988,240(4857):1339-1341
In situ hybridization with complementary DNA probes for nerve growth factor (NGF) was used to identify cells containing NGF messenger RNA in rat and mouse brain. The most intense labeling occurred in hippocampus, where hybridizing neurons were found in the dentate gyrus and the pyramidal cell layer. The neuronal identity of NGF mRNA-containing cells was further assessed by a loss of NGF-hybridizing mRNA in hippocampal areas where neurons had been destroyed by kainic acid or colchicine. RNA blot analysis also revealed a considerable decrease in the level of NGF mRNA in rat dentate gyrus after a lesion was produced by colchicine. This lesion also caused a decrease in the level of Thy-1 mRNA and an increase in the level of glial fibrillary acidic protein mRNA. Neuronal death was thus associated with the disappearance of NGF mRNA. These results suggest a synthesis of NGF by neurons in the brain and imply that, in hippocampus, NGF influences NGF-sensitive neurons through neuron-to-neuron interactions. 相似文献
20.
F Baldino T M O'Kane S Fitzpatrick-McElligott B Wolfson 《Science (New York, N.Y.)》1988,241(4868):978-981
Previous studies have shown that adrenalectomy augments arginine vasopressin (AVP) messenger RNA levels in the adult paraventricular nucleus. It is now demonstrated that unilateral lesions in the lateral septal nucleus enhance the adrenalectomy-induced expression of AVP mRNA. This effect was entirely ipsilateral to the lesion and most prominent in the rostral paraventricular nucleus and related nuclei. Moreover, AVP and AVP mRNA were found to be colocalized with oxytocin in a few neurons. These results indicate that mRNA expression is modulated by synaptic influences and raise the possibility that synaptically mediated selection of neuronal phenotypes is a dynamic feature of the mature central nervous system. 相似文献