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1.
Endocrinology ; 155(5): 1887-98, 2014 May.
Article in English | MEDLINE | ID: mdl-24601879

ABSTRACT

Traumatic brain injury is a leading cause of hypopituitarism, which compromises patients' recovery, quality of life, and life span. To date, there are no means other than standardized animal studies to provide insights into the mechanisms of posttraumatic hypopituitarism. We have found that GH levels were impaired after inducing a controlled cortical impact (CCI) in mice. Furthermore, GHRH stimulation enhanced GH to lower level in injured than in control or sham mice. Because many characteristics were unchanged in the pituitary glands of CCI mice, we looked for changes at the hypothalamic level. Hypertrophied astrocytes were seen both within the arcuate nucleus and the median eminence, two pivotal structures of the GH axis, spatially remote to the injury site. In the arcuate nucleus, GHRH neurons were unaltered. In the median eminence, injured mice exhibited unexpected alterations. First, the distributions of claudin-1 and zonula occludens-1 between tanycytes were disorganized, suggesting tight junction disruptions. Second, endogenous IgG was increased in the vicinity of the third ventricle, suggesting abnormal barrier properties after CCI. Third, intracerebroventricular injection of a fluorescent-dextran derivative highly stained the hypothalamic parenchyma only after CCI, demonstrating an increased permeability of the third ventricle edges. This alteration of the third ventricle might jeopardize the communication between the hypothalamus and the pituitary gland. In conclusion, the phenotype of CCI mice had similarities to the posttraumatic hypopituitarism seen in humans with intact pituitary gland and pituitary stalk. It is the first report of a pathological status in which tanycyte dysfunctions appear as a major acquired syndrome.


Subject(s)
Brain Injuries/physiopathology , Disease Models, Animal , Ependymoglial Cells/pathology , Hypopituitarism/etiology , Hypothalamus/pathology , Neurons/pathology , Tight Junctions/pathology , Animals , Arcuate Nucleus of Hypothalamus/immunology , Arcuate Nucleus of Hypothalamus/metabolism , Arcuate Nucleus of Hypothalamus/pathology , Biomarkers/metabolism , Ependymoglial Cells/immunology , Ependymoglial Cells/metabolism , Gene Expression Regulation , Green Fluorescent Proteins/genetics , Green Fluorescent Proteins/metabolism , Growth Hormone-Releasing Hormone/genetics , Growth Hormone-Releasing Hormone/metabolism , Hypopituitarism/immunology , Hypopituitarism/metabolism , Hypopituitarism/pathology , Hypothalamus/immunology , Hypothalamus/metabolism , Immunoglobulin G/metabolism , Male , Median Eminence/immunology , Median Eminence/metabolism , Median Eminence/pathology , Mice , Mice, Transgenic , Nerve Tissue Proteins/genetics , Nerve Tissue Proteins/metabolism , Neurons/immunology , Neurons/metabolism , Permeability , Recombinant Fusion Proteins/metabolism , Third Ventricle/immunology , Third Ventricle/metabolism , Third Ventricle/pathology , Tight Junctions/immunology , Tight Junctions/metabolism
2.
Endocrinology ; 155(5): 2000-8, 2014 May.
Article in English | MEDLINE | ID: mdl-24635351

ABSTRACT

The enzyme type 2 deiodinase (D2) is a major determinant of T3 production in the central nervous system. It is highly expressed in tanycytes, a specialized cell type lining the wall of the third ventricle. During acute inflammation, the expression of D2 in tanycytes is up-regulated by a mechanism that is poorly understood at present, but we hypothesized that cJun N-terminal kinase 1 (JNK1) and v-rel avian reticuloendotheliosis viral oncogene homolog A (RelA) (the 65 kD subunit of NFκB) inflammatory signal transduction pathways are involved. In a mouse model for acute inflammation, we studied the effects of lipopolysaccharide (LPS) on mRNA expression of D2, JNK1, and RelA in the periventricular area (PE) and the arcuate nucleus-median eminence of the hypothalamus. We next investigated LPS-induced D2 expression in primary tanycyte cell cultures. In the PE, the expression of D2 was increased by LPS. In the arcuate nucleus, but not in the PE, we found increased RelA mRNA expression. Likewise, LPS increased D2 and RelA mRNA expression in primary tanycyte cell cultures, whereas JNK1 mRNA expression did not change. Phosphorylation of RelA and JNK1 was increased in tanycyte cell cultures 15-60 minutes after LPS stimulation, confirming activation of these pathways. Finally, inhibition of RelA with the chemical inhibitors sulfasalazine and 4-Methyl-N¹-(3-phenylpropyl)benzene-1,2-diamine (JSH-23) in tanycyte cell cultures prevented the LPS-induced D2 increase. We conclude that NFκB signaling is essential for the up-regulation of D2 in tanycytes during inflammation.


Subject(s)
Endotoxins/toxicity , Enzyme Induction/drug effects , Ependymoglial Cells/drug effects , Iodide Peroxidase/biosynthesis , NF-kappa B/metabolism , Nerve Tissue Proteins/biosynthesis , Signal Transduction/drug effects , Animals , Arcuate Nucleus of Hypothalamus/cytology , Arcuate Nucleus of Hypothalamus/drug effects , Arcuate Nucleus of Hypothalamus/immunology , Arcuate Nucleus of Hypothalamus/metabolism , Cells, Cultured , Ependymoglial Cells/cytology , Ependymoglial Cells/immunology , Ependymoglial Cells/metabolism , Female , Iodide Peroxidase/genetics , Iodide Peroxidase/metabolism , Male , Median Eminence/cytology , Median Eminence/drug effects , Median Eminence/immunology , Median Eminence/metabolism , Mice , Mice, 129 Strain , Midline Thalamic Nuclei/cytology , Midline Thalamic Nuclei/drug effects , Midline Thalamic Nuclei/immunology , Midline Thalamic Nuclei/metabolism , Mitogen-Activated Protein Kinase 8/genetics , Mitogen-Activated Protein Kinase 8/metabolism , Nerve Tissue Proteins/genetics , Nerve Tissue Proteins/metabolism , Rats , Rats, Wistar , Transcription Factor RelA/biosynthesis , Transcription Factor RelA/genetics , Transcription Factor RelA/metabolism , Iodothyronine Deiodinase Type II
3.
Neuroimmunomodulation ; 14(3-4): 200-5, 2007.
Article in English | MEDLINE | ID: mdl-18073515

ABSTRACT

Alcoholic beverages are characterized by their fermented versus distilled origin and also by their degree of alcohol. The toxic effects of chronic alcohol consumption have been widely studied. However, there is less evidence about possible beneficial effects of moderate alcohol intake. This work was aimed at evaluating the effects of moderate alcohol consumption (beer or ethanol) on plasma hormone concentrations, blood and thymus lymphocyte phenotypes and brain neurotransmitter levels. For this purpose, 40 adult Wistar male rats were administered ethanol or beer for 4 weeks (experimental groups). Age-matched rats were administered beer without alcohol or water to be used as controls. Rats were killed by decapitation and plasma from the trunk blood was collected to measure plasma prolactin, growth hormone and ACTH concentrations by homologous specific double antibody radioimmunoassays. Thymus and blood lymphocyte subsets were measured by flow cytometry. Neurotransmitter concentrations [dopamine, gamma-aminobutyric acid (GABA) and taurine] were measured by high pressure liquid chromatography in the median eminence and the pituitary. Blood and thymus lymphocyte subsets were not significantly changed by either ethanol or beer consumption, compared to controls. Plasma prolactin levels significantly decreased in ethanol-administered groups (p < 0.05) compared to control animals drinking water, although plasma levels of growth hormone and ACTH were not modified by either alcohol used. Dopamine and GABA concentrations in the median eminence or in the adenohypophysis remained unmodified by moderate beer or ethanol consumption. However, taurine concentration was significantly increased in the pituitary (p < 0.05) in the group drinking ethanol compared to those groups drinking beer with or without alcohol. These data suggest that moderate alcohol consumption may change the regulatory mechanism of prolactin secretion. Whether these modifications have a physiological significance deserves further research.


Subject(s)
Alcoholic Beverages/adverse effects , Ethanol/pharmacology , Hypothalamo-Hypophyseal System/drug effects , Immune System/drug effects , Neuroimmunomodulation/drug effects , Prolactin/drug effects , Animals , Central Nervous System Depressants/pharmacology , Dopamine/metabolism , Hypothalamo-Hypophyseal System/immunology , Hypothalamo-Hypophyseal System/metabolism , Immune System/immunology , Lymphocytes/drug effects , Lymphocytes/immunology , Male , Median Eminence/drug effects , Median Eminence/immunology , Median Eminence/metabolism , Neuroimmunomodulation/immunology , Pituitary Gland, Anterior/drug effects , Pituitary Gland, Anterior/immunology , Pituitary Gland, Anterior/metabolism , Prolactin/blood , Prolactin/metabolism , Rats , Rats, Wistar , Taurine/metabolism , Thymus Gland/cytology , Thymus Gland/drug effects , Thymus Gland/immunology , gamma-Aminobutyric Acid/metabolism
4.
J Clin Endocrinol Metab ; 90(7): 4108-11, 2005 Jul.
Article in English | MEDLINE | ID: mdl-15855266

ABSTRACT

CONTEXT: Autoantibodies to adenohypophyseal endocrine cells or to vasopressin neurohypophyseal neurons have long been known. Conversely, autoimmune targeting of further hypothalamic-hypophyseal structures, such as the blood-brain barrier-deprived median eminence, has been little studied. OBJECTIVE AND METHODS: We studied a case of autoimmune polyendocrine syndrome type I with GH secretory deficiency, a distinctly rare event in autoimmune polyendocrine syndrome type I. We used rat and bovine tissue substrates to study autoantibodies against hypothalamic-hypophyseal nerve structures and endocrine cells. RESULTS: In the study case, circulating autoantibodies selectively decorated median eminence dopaminergic nerve terminals, as well as pituitary gonadotropes, but not GHRH nerve terminals or pituitary somatotropes. Such autoantibodies appeared de novo in parallel with the onset of GH secretory deficiency, whereas no median eminence labeling was found in patients suffering of idiopathic GH deficiency (n = 7) or in healthy controls (n = 23). CONCLUSIONS: The pathophysiological significance of our patient's autoantibodies remains to be confirmed. Nonetheless, the heterogeneous neuroendocrine structures of the median eminence are pointed out as potential immune targets, relevant to autoimmune polyendocrinopathy, as well as to a wide range of other conditions.


Subject(s)
Median Eminence/immunology , Polyendocrinopathies, Autoimmune/immunology , Adolescent , Animals , Aromatic-L-Amino-Acid Decarboxylases/immunology , Autoantibodies/blood , Cattle , Child , Child, Preschool , Female , Gonadotropin-Releasing Hormone/immunology , Human Growth Hormone/deficiency , Human Growth Hormone/metabolism , Humans , Male , Rats , Rats, Sprague-Dawley , Tyrosine 3-Monooxygenase/immunology
5.
J Neuroimmunol ; 141(1-2): 65-73, 2003 Aug.
Article in English | MEDLINE | ID: mdl-12965255

ABSTRACT

We analyzed expression of osteopontin (OPN), a cytokine regulating tissue repair and inflammation, in astrocytes and microglia in response to systemic lipopolysaccharide (LPS) administration (250 microg/100 g). OPN mRNA expression appeared in subpial astrocytes as early as 6 h, and then spread over the brain parenchyma. The signal for OPN mRNA reached a peak at 24 h post-injection, and returned to basal levels after 48 h. Changes in OPN immunoreactivity in the LPS-injected rat mirrored OPN mRNA induction patterns. These results provide the first evidence of OPN induction in astrocytes and microglia following peripheral immune challenge, and suggest that OPN may play a key role in the pathogenesis of neuroinflammation.


Subject(s)
Brain/immunology , Brain/metabolism , Gene Expression Regulation/immunology , Lipopolysaccharides/administration & dosage , RNA, Messenger/biosynthesis , Sialoglycoproteins/biosynthesis , Sialoglycoproteins/genetics , Animals , Arcuate Nucleus of Hypothalamus/immunology , Arcuate Nucleus of Hypothalamus/metabolism , Arcuate Nucleus of Hypothalamus/ultrastructure , Brain/ultrastructure , Hypothalamus/immunology , Hypothalamus/metabolism , Hypothalamus/ultrastructure , Immunohistochemistry , In Situ Hybridization , Injections, Intraperitoneal , Male , Median Eminence/immunology , Median Eminence/metabolism , Median Eminence/ultrastructure , Microscopy, Immunoelectron , Osteopontin , Rats , Rats, Sprague-Dawley , Sialoglycoproteins/ultrastructure , Supraoptic Nucleus/immunology , Supraoptic Nucleus/metabolism , Supraoptic Nucleus/ultrastructure , Time Factors
6.
Cell Tissue Res ; 308(2): 241-53, 2002 May.
Article in English | MEDLINE | ID: mdl-12037581

ABSTRACT

Tanycytes are specialized ependymal cells lining the infundibular recess of the third ventricle of the cerebrum. Early and recent investigations involve tanycytes in the mechanism of gonadotropin-releasing hormone (GnRH) release to the portal blood. The present investigation was performed to obtain a specific immunological marker of tanycytes and to identify the compound(s) responsible for this labeling. After 30 days of organ culture, explants of bovine median eminence formed spherical structures mostly constituted by tanycytes. These tanycyte spheres were xenotransplanted to rats, and the antibodies raised by the host animals against the transplanted living tanycytes were used for immunochemical studies of the bovine and rat median eminence. This antiserum immunoreacted with two compounds of 60 kDa and 85 kDa present in extracts of bovine and rat median eminence. The individual immunoblotting analysis of rat medial basal hypothalami showed a decrease in the amount of the 85-kDa compound in castrated rats as compared to control rats processed at oestrus and dioestrus. The antiserum, labeled as anti-P85, when used for immunostaining of sections throughout the rat central nervous system, immunoreacted specifically with the hypothalamic tanycytes. Within tanycytes, P-85 immunoreactivity was exclusively present in the basal processes. It is suggested that the 85-kDa and 60-kDa compounds correspond to two novel proteins selectively expressed by tanycytes. The possibility that they are secretory proteins involved in GnRH release is discussed. Anti-P85 appears to be the first specific marker of hypothalamic tanycytes.


Subject(s)
Hypothalamus/cytology , Hypothalamus/immunology , Median Eminence/immunology , Median Eminence/transplantation , Transplantation, Heterologous/immunology , Animals , Cattle , Female , Hypothalamus/ultrastructure , Immunoblotting , Immunohistochemistry , Male , Microscopy, Electron , Nerve Tissue Proteins/metabolism , Organ Culture Techniques , Rats , Rats, Sprague-Dawley , Tissue Extracts/immunology , Vacuoles/ultrastructure
7.
J Neuroendocrinol ; 12(12): 1186-93, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11106976

ABSTRACT

Lewis rats exhibit multiple defects in their hypothalamus-pituitary-adrenal (HPA) system that are considered to play a causal role in the susceptibility of this strain to autoimmune diseases, i.e. experimental allergic encephalomyelitis (EAE). In the present study, we aimed to modulate the HPA response of the Lewis rat and establish its consequences for the susceptibility to EAE. Because in Wistar rats, single administration of interleukin (IL)-beta (priming) is known to induce long-lasting (weeks) sensitization of HPA responses to stressors and immune stimuli, Lewis rats were given a single dose of hIL-1beta or vehicle 1 week prior to induction of EAE by immunization with myelin basic protein (MBP). Subsequently, neurological deficits were monitored once daily. The results show that IL-1 priming markedly suppresses the neurological symptoms of EAE, without affecting the onset or duration of the disease. Measurement of vasopressin and corticotropin releasing hormone (CRH) in the external zone of the median eminence revealed that, as compared to Wistar rats, Lewis rats exhibit low vasopressin but identical CRH, and that IL-1 priming increases (0.001) vasopressin without affecting CRH stores, which is consistent with a shift to vasopressin-dominated control of adrenocorticotropic hormone (ACTH) secretion as described in Wistar rats under conditions of HPA hyper(re)activity. However, IL-1 priming did not affect a.m. corticosterone levels following immunization with MBP or during the clinical phase of EAE. IL-1 priming of Lewis rats attenuated the ACTH responses to an IL-1 challenge 11 days later, which may relate to an increase in resting corticosterone levels. Thus, the mechanisms underlying IL-1 induced suppression of EAE are not related to enhanced HPA responses. In addition, we did not find IL-1 priming-induced alterations in MBP-specific immunoglobulin (Ig)M, IgG1, IgGa and IgGb plasma titres, or gross alterations in T cell activation as reflected in spontaneous or concanavalin-induced T cell proliferation. We therefore speculate that IL-1-induced elevation of resting corticosterone levels may influence the development of EAE.


Subject(s)
Encephalomyelitis, Autoimmune, Experimental/drug therapy , Encephalomyelitis, Autoimmune, Experimental/immunology , Interleukin-1/pharmacology , Adrenocorticotropic Hormone/blood , Animals , Cell Division/drug effects , Cell Division/immunology , Concanavalin A/pharmacology , Corticosterone/blood , Corticotropin-Releasing Hormone/analysis , Corticotropin-Releasing Hormone/immunology , Encephalomyelitis, Autoimmune, Experimental/chemically induced , Immunization , Immunoglobulin G/blood , Immunoglobulin M/blood , Male , Median Eminence/chemistry , Median Eminence/drug effects , Median Eminence/immunology , Myelin Basic Protein/immunology , Myelin Basic Protein/pharmacology , Neurologic Examination , Rats , Rats, Inbred Lew , Rats, Wistar , T-Lymphocytes/cytology , T-Lymphocytes/drug effects , T-Lymphocytes/immunology , Vasopressins/analysis , Vasopressins/immunology
8.
Chronobiol Int ; 14(3): 253-65, 1997 May.
Article in English | MEDLINE | ID: mdl-9167886

ABSTRACT

The effect of Freund's adjuvant injection on 24-h variation of circulating ACTH, prolactin, growth hormone (GH), and thyroid-stimulating hormone (TSH) levels, and of norepinephrine (NE) content, and dopamine (DA) and serotonin (5HT) turnover in median eminence, was examined in adult rats kept under light between 0800 and 2000 h daily. Groups of 6-10 animals received Freund's complete adjuvant or its vehicle at 1100 h 3 days before sacrifice and were killed by decapitation at six different time intervals throughout a 24-h cycle. In rats injected with adjuvant's vehicle, serum ACTH and prolactin exhibited peak values around the light-dark transition (p < 0.0001 and < 0.04, respectively), while the maximum in TSH was found in the late afternoon (p < 0.0001, one-way ANOVA). GH levels did not vary on a 24-h basis. In Freund's adjuvant-injected rats, 24-h variations of TSH levels became blunted, while 24-h variations of prolactin and ACTH persisted. Freund's adjuvant augmented serum ACTH and prolactin levels, and decreased GH and TSH levels (p < 0.0007, factorial ANOVA). Median-eminence NE content, and turnover of DA, assessed by measuring dihydroxyphenylacetic acid, DOPAC/DA ratio, and of 5HT, assessed by measuring 5-hydroxyindoleacetic acid, HIAA/5HT ratio, varied on a 24-h basis in rats receiving adjuvant's vehicle (p < 0.02). Median-eminence NE content attained its maximum at 1600-2000 h, while maxima in DOPA/DA and HIAA/5HT ratios occurred at 0400 h. Injection with Freund's adjuvant reduced the amplitude of the daily variation of NE content, shifted the maximum of DOPAC/DA ratio toward the light-dark transition, and blunted the daily variation in HIAA/5HT ratio in median eminence. The administration at 1200 of the immunosuppressant drug cyclosporine (5 mg/kg, 5 days) restored the augmented ACTH and prolactin levels (p < 0.0001, factorial ANOVA) and depressed GH and TSH levels (p < 0.02) found in Freund's adjuvant-injected rats. Cyclosporine was also effective in restoring 24-h rhythmicity of serum ACTH and TSH, but not of prolactin, levels. Cyclosporine did not modify the effect of Freund's adjuvant on time-of-day changes of median-eminence NE content, but it was effective in counteracting the changes of DA and 5HT turnover found after immunization. The results are compatible with a significant effect of immune-mediated inflammatory response at an early phase after Freund's adjuvant injection on ACTH, GH, prolactin, and TSH release, which is partially sensitive to immunosuppression by cyclosporine.


Subject(s)
Arthritis, Experimental/blood , Arthritis, Experimental/metabolism , Biogenic Monoamines/metabolism , Circadian Rhythm/physiology , Hormones/blood , Median Eminence/metabolism , 3,4-Dihydroxyphenylacetic Acid/metabolism , Adrenocorticotropic Hormone/blood , Animals , Arthritis, Experimental/etiology , Circadian Rhythm/immunology , Dopamine/metabolism , Freund's Adjuvant/administration & dosage , Growth Hormone/blood , Hydroxyindoleacetic Acid/metabolism , Male , Median Eminence/immunology , Norepinephrine/metabolism , Prolactin/blood , Rats , Rats, Wistar , Serotonin/metabolism , Thyrotropin/blood
9.
Brain Res ; 639(2): 233-9, 1994 Mar 14.
Article in English | MEDLINE | ID: mdl-8205477

ABSTRACT

A system of intraventricular neuronal perikarya and processes known as the supraependymal neuronal complex (SENC) is located on the floor of the third ventricle and innervates the neurohypophysis of the golden hamster (Mesocricetus auratus). Immunocytochemical techniques were used to determine if oxytocin and/or vasopressin are present in the neuronal elements of the SENC. Oxytocinergic fibers were observed to breach the ependyma of the median eminence and enter the neuropil of the SENC. Some of these fibers traverse the SENC to reach the adjacent ependymal surface and terminate on the floor of the third ventricle while others terminate within the neuropil of the SENC. These oxytocinergic fibers may be involved in the secretion of oxytocin into the cerebrospinal fluid (CSF). Vasopressinergic fibers were detected in the neuropil of the SENC in only one of four specimens examined and are assumed to be aberrant processes from the hypothalamo-neurohypophysial tract. Neither oxytocin nor vasopressin were detected in the neurons intrinsic to the SENC. The function of the SENC is unknown, but it may be involved in regulatory processes in which CSF oxytocin has been implicated, such as osmotic homeostasis and/or cardiovascular reflexes.


Subject(s)
Cerebral Ventricles/metabolism , Neurons/metabolism , Oxytocin/metabolism , Animals , Cerebral Ventricles/cytology , Cricetinae , Female , Immunohistochemistry , Male , Median Eminence/cytology , Median Eminence/immunology , Median Eminence/metabolism , Mesocricetus , Neurons/immunology , Oxytocin/immunology , Vasopressins/immunology , Vasopressins/metabolism
10.
J Neuroimmunol ; 48(1): 1-11, 1993 Oct.
Article in English | MEDLINE | ID: mdl-8227303

ABSTRACT

The terminals of the hypothalamic gonadotrophin hormone-releasing hormone (GnRH) neurons are located within the median eminence and thereby extend beyond the protection of the blood-brain barrier. Thus, these terminals may be subjected to direct autoimmune action in animals that are actively immunised against GnRH. Boars (male pigs) (n = 108) were actively immunised against GnRH by two successive injections with synthetic GnRH, covalently coupled to KLH and dissolved in CFA or IFA. They were killed at 26 weeks of age. Immunised boars were selected on the basis of the resultant testes size, which indicates the effectiveness of the immunisation. The hypothalami of 25 selected animals were studied by histological and immunocytochemical techniques and compared with the hypothalami of three sham- and nine control animals. In the immunised animals, changes in the GnRH system had taken place. These comprised dystrophy of the perikarya and a sharp decrease of the GnRH immunocytochemical reactivity in the terminals within the median eminence. In addition, various degrees of inflammatory reactions were present, particularly within the median eminence. These consisted of tissue disruption by edema, collapse of the capillaries, fibrosis and infiltration with fibroblasts. In addition, accumulations of neurosecretum within the median eminence in combination with hypertrophy of magnocellular neurons within the hypothalamus were present. The reactions were restricted to the median eminence and did not involve other neurohemal organs or other parts of the hypothalamus. A correlation could be established between the incidence of the lesions and the effectiveness of the GnRH autoimmunity (as indicated by the size and endocrine function of the gonads and the anti-GnRH titres). Changes in extra- and intracellular IgG immunocytochemical reactivity within the median eminence indicated the involvement of IgG. The effects were absent from control and sham vaccinated animals and after vaccinations with other compositions of the vaccine. Thus, hypothalamic lesions have been observed in this selected group of animals, vaccinated against GnRH with this particular vaccine.


Subject(s)
Autoantibodies/immunology , Gonadotropin-Releasing Hormone/immunology , Median Eminence/pathology , Amino Acid Sequence , Animals , Glial Fibrillary Acidic Protein/analysis , Glial Fibrillary Acidic Protein/immunology , Gonadotropin-Releasing Hormone/analysis , Immunoglobulin G/immunology , Male , Median Eminence/immunology , Molecular Sequence Data , Swine , Vaccination
11.
J Comp Neurol ; 326(1): 112-20, 1992 Dec 01.
Article in English | MEDLINE | ID: mdl-1479064

ABSTRACT

The enkephalin-immunoreactive neurons that project to the external zone of the median eminence were identified on thin paraffin and thick vibratome sections using a combination of retrograde labeling with peripherally administered Fluoro-Gold and immunocytochemistry. The vast majority of the enkephalin-immunoreactive neurons that project to the external zone of the median eminence (ME) reside in the paraventricular nucleus (PVN) of the hypothalamus. Within the PVN, the majority of these hypophysiotropic neurons are located in the medial parvicellular subdivision, while a smaller number can be detected in the anterior and the periventricular subdivisions. Although many enkephalin-immunoreactive neurons are present in other hypophysiotropic areas of the hypothalamus, such as the medial preoptic area, the anterior periventricular area, and the arcuate nucleus, only a few of these can be retrogradely labeled from the ME. These results provide morphological evidence for the key role of paraventricular enkephalin-immunoreactive neurons in the regulation of neuroendocrine functions.


Subject(s)
Enkephalins/metabolism , Median Eminence/cytology , Neurons/metabolism , Paraventricular Hypothalamic Nucleus/cytology , Stilbamidines , Animals , Enkephalins/immunology , Fluorescent Dyes , Immunohistochemistry , Male , Median Eminence/immunology , Neural Pathways/cytology , Neurons/immunology , Paraventricular Hypothalamic Nucleus/immunology , Rats , Rats, Sprague-Dawley
12.
Cell Tissue Res ; 255(1): 139-47, 1989 Jan.
Article in English | MEDLINE | ID: mdl-2472216

ABSTRACT

Immunoreactive galanin-like material was recently shown to co-exist with vasopressin in parvocellular and magnocellular perikarya of the paraventricular nucleus in the anterior hypothalamus of the rat (Melander et al. 1986). Since this distribution pattern differed from our observation of oxytocin-associated galanin-like immunoreactivity (LI) in the neurohypophysis, we compared in series of 0.5-microns thick sections the localisation of galanin-LI with the localisation of oxytocin and vasopressin/dynorphin in the hypothalamus, the median eminence and the neurohypophysis. In the oxytocin system, galanin-LI was intense in oxytocin varicosities of the neurohypophysis. Oxytocin perikarya of the hypothalamic supraoptic and paraventricular nuclei exhibited galanin-LI only after intraventricular injection of colchicine and when sections were treated with trypsin prior to application of the antibody. In the vasopressin/dynorphin system galanin-LI was intense in hypothalamic perikarya after colchicine injection and in neurohypophysial varicosities after treatment of the sections with trypsin. In these neurones, galanin-LI was absent or weak in all elements when treatments with colchicine or trypsin were omitted. Galanin-LI in the neurohypophysis was not co-localised with the numerous fine endings showing GABA-LI. These observations indicate that galanin-like material coexists with vasopressin and oxytocin in the respective magnocellular neurones, although not always in an immunoreactive form.


Subject(s)
Hypothalamus/immunology , Neurons/immunology , Peptides/immunology , Pituitary Gland, Posterior/immunology , Animals , Catecholamines/metabolism , Female , Galanin , Hypothalamus/cytology , Hypothalamus/metabolism , Immunohistochemistry , Male , Median Eminence/cytology , Median Eminence/immunology , Median Eminence/metabolism , Neurons/drug effects , Neurons/metabolism , Peptides/metabolism , Pituitary Gland, Posterior/cytology , Pituitary Gland, Posterior/metabolism , Rats , Rats, Inbred Strains , Trypsin/pharmacology
13.
Mol Cell Endocrinol ; 53(3): 245-50, 1987 Oct.
Article in English | MEDLINE | ID: mdl-3666300

ABSTRACT

The distribution and molecular forms of bombesin-like immunoreactivity (BLI) were determined in the ovine median eminence using a new, C-terminally directed antiserum. BLI was confined to neurons of the external zone of the median eminence, near small blood vessels, many of which also were immunoreactive for CRF. Each median eminence contained about 10 pmol of BLI (533 pmol/g tissue). Gel filtration and reverse-phase high pressure liquid chromatography (HPLC) demonstrated the existence of two molecular forms of BLI, which co-eluted with porcine gastrin releasing peptide (GRP)1-27 and GRP18-27 in a molar ratio of 1:2. The presence of BLI in the ovine median eminence and its co-localization in some neurons with CRF, suggest a possible role for peptides of the bombesin family in the regulation of pituitary function.


Subject(s)
Bombesin/analysis , Median Eminence/immunology , Animals , Chromatography, High Pressure Liquid , Immune Sera , Immunohistochemistry , Molecular Conformation , Peptide Fragments/analysis , Radioimmunoassay , Sheep
14.
J Neurochem ; 47(1): 133-8, 1986 Jul.
Article in English | MEDLINE | ID: mdl-3711894

ABSTRACT

An antiserum was raised to adipokinetic hormone (AKH), a 10-amino-acid-residue peptide found in the arthropod Locusta migratoria. The antiserum demonstrated not only immunocytochemical reaction with some other arthropod species, but also stained many areas of the rat CNS, certain islet cells of the pancreas, and some anterior pituitary cells. The pattern of staining was unlike that for any known rat neuropeptide or hormone. With the antiserum used as the detection system, HPLC and high-voltage electrophoresis yielded two peptides that were purified to homogeneity from rat hypothalamic median eminence. These peptides have unique amino acid compositions, indicating they may be heretofore unknown rat neuropeptides.


Subject(s)
Insect Hormones/immunology , Peptides/immunology , Rats/immunology , Animals , Carcinoma/immunology , Carcinoma/pathology , Cell Line , Chromatography, High Pressure Liquid , Histocytochemistry , Immune Sera/immunology , Immunochemistry , Median Eminence/immunology , Pancreas/immunology , Peptides/isolation & purification , Thyroid Neoplasms/immunology , Thyroid Neoplasms/pathology
15.
Ann Endocrinol (Paris) ; 46(1): 64-6, 1985.
Article in French | MEDLINE | ID: mdl-3909927

ABSTRACT

Confrontations of immuno-stainings as well as sequential stainings with corticoliberin and vasopressin antisera were performed on contiguous sections of human median eminence (ME) or hypothalamic paraventricular nucleus (PVN). Results show that a double immunoreactivity to both IS is expressed in some parvicellular PVN perikarya, and suggest that such a double immunoreactivity can be possible in some ME fibers. Similar results had been previously obtained in animals only under experimental conditions.


Subject(s)
Corticotropin-Releasing Hormone/immunology , Hypothalamus/cytology , Neurons/immunology , Vasopressins/immunology , Fluorescent Antibody Technique , Humans , Immune Sera/immunology , Median Eminence/immunology , Paraventricular Hypothalamic Nucleus/immunology
16.
Brain Res ; 278(1-2): 258-61, 1983 Nov 14.
Article in English | MEDLINE | ID: mdl-6139151

ABSTRACT

Concentrations of dynorphin and alpha-neo-endorphin were measured in rat supraoptic and paraventricular nuclei, median eminence and posterior pituitary. Paraventricular lesions did not alter the level of either peptide in the median eminence or posterior pituitary. Knife cuts in the lateral retrochiasmatic area that severed the supraoptico-hypophyseal tract reduced dynorphin and alpha-neo-endorphin levels by 64-80% in the posterior pituitary and by somewhat less in the median eminence. Knife cuts in the vicinity of the supraoptic nucleus that did not interrupt the supraoptico-hypophyseal tract did not affect peptide concentrations in the posterior pituitary. Our data suggest that dynorphin and alpha-neo-endorphin in the posterior pituitary are in processes of supraoptic nucleus neurons. These neurons also project to the median eminence which may receive fibers from other dynorphin and alpha-neo-endorphin containing cells too.


Subject(s)
Endorphins/immunology , Hypothalamo-Hypophyseal System/immunology , Protein Precursors/immunology , Rats/physiology , Animals , Dynorphins , Male , Median Eminence/immunology , Pituitary Gland, Posterior/immunology , Rats, Inbred Strains , Tissue Distribution
17.
Neurosci Lett ; 37(1): 43-9, 1983 May 27.
Article in English | MEDLINE | ID: mdl-6348596

ABSTRACT

The zona externa of the median eminence was found completely depleted of corticoliberin-like immunoreactivity (CLI) and of vasopressin-like immunoreactivity (VLI) 12-14 h and 22-24 h after bilateral adrenalectomy. Amount of CLI increased to the level of untreated rats 5 days after this operation while amount of VLI rose higher than in control animals. The same was found 20 days after surgery. These results emphasize the involvement of two infundibular neurosecretory systems--CLI and VLI--in the regulation of the pituitary--adrenal axis.


Subject(s)
Adrenalectomy , Corticotropin-Releasing Hormone/immunology , Median Eminence/immunology , Rats/immunology , Vasopressins/immunology , Animals , Histocytochemistry , Immunologic Techniques , Male , Rats, Inbred Strains , Time Factors
18.
Acta Morphol Hung ; 31(4): 365-9, 1983.
Article in English | MEDLINE | ID: mdl-6198885

ABSTRACT

A new immunohistological method was elaborated for the light-microscopic detection of two tissue antigens in the same section. One of the antigens was visualized by the silver-gold intensified peroxidase-antiperoxidase complex (PAP)-diaminobenzidine (DAB) method resulting in a black coloured end-product. The other antigen was labelled by the brown reaction-product of the traditional PAP-DAB method. Both reaction-products are stable, electron-dense and they can clearly be distinguished from each other.


Subject(s)
Antigens/analysis , Immunoenzyme Techniques , Median Eminence/immunology , Pituitary Gland, Anterior/immunology , Animals , Female , Follicle Stimulating Hormone/analysis , Gonadotropin-Releasing Hormone/analysis , Growth Hormone/analysis , Median Eminence/analysis , Pituitary Gland, Anterior/analysis , Rats , Silver , Somatostatin/analysis , Staining and Labeling
19.
Endocrinology ; 96(1): 135-42, 1975 Jan.
Article in English | MEDLINE | ID: mdl-1089060

ABSTRACT

With the use of rabbit anti-LH-RH serum, a system of delicate nerve fibers and terminals which contain immunoreactive LH-RH can be demonstrated in the median eminence of the rat, corresponding exactly to the tubero-infundibular tract as described earlier with the aid of classical neurophistological methods. The delicate fiber system can be traced to the region of the rectrochiasmatic area and especially to that of the arcuate nucleus but not farther. Nerve cells do not show any immunopositive reaction for LH-RH in the experimental conditions studied. LH-RH positive nerve fibers terminate on or in the immediate vicinity of the capillary loops penetrating the median eminence.


Subject(s)
Gonadotropin-Releasing Hormone/immunology , Hypothalamus/innervation , Nerve Endings/cytology , Neurons/cytology , Animals , Antigen-Antibody Reactions , Cytological Techniques , Hypothalamus/cytology , Immunologic Techniques , Median Eminence/cytology , Median Eminence/immunology , Nerve Endings/immunology , Neurons/immunology , Peroxidases , Rabbits/immunology , Rats
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