Made available in DSpace on 2016-08-19T18:16:07Z (GMT). No. of bitstreams: 1 Dissertacao Kenya Mara.pdf: 799958 bytes, checksum: cb09cc18255c1c97c36d29edcb749fd9 (MD5) Previous issue date: 2012-07-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The pituitary adenomas are the most common cause of a sellar mass of the third decade onwards, accounting for more than 10% of intracranial tumors. Recent studies indicate a prevalence of up to 77.6 per 100,000 inhabitants. Postoperative complications of hypophyseal surgery include: lesion of the carotid artery, cerebrospinal fluid leak, nasal septum perforation, Diabetes Insipidus, Syndrome of Inappropriate Antidiuretic Hormone Secretion, adrenal insufficiency, epistaxis, hyponatremia, sinusitis, visual loss, transient paralysis of the cranial nerve, sphenoidal abscess, meningitis, hemorrhage in the tumor bed and hypothalamic injury. Being the last three the ones of the highest mortality. This study evaluated 28 patients undergoing surgery of Pituitary tumor by transsphenoidal way and 2 by transcranial and watched the most common complications such as: cerebrospinal fluid leak (30 %), Diabetes Insipidus (26.6 %) and adrenal insufficiency (13.3 %) were found more frequently , followed by bleeding in the tumor bed (6.7%), pneumonia (6.7%) and sinusitis (3.3%). The prevalence of mortality was 6.7%. Endocrine complications can lead to death if not treated timely. A thorough clinical and laboratory evaluation by a multidisciplinary team is necessary for good performance in the management of postoperative complications of patients undergoing resection of pituitary tumor, since anticipate complications and minimize its risks. / Os adenomas hipofisários são a causa mais comum de massa selar da terceira década em diante, sendo responsável por mais de 10% das neoplasias intracranianas. Estudos recentes apontam para uma prevalência de até 77,6 por 100.000 habitantes. A ressecção cirúrgica pode ser necessária e as complicações pós-operatórias de cirurgia hipofisária incluem: lesão de artéria carótida, fistula liquorica, perfuração de septo nasal, diabetes insipidus, SIADH, insuficiência adrenal, epistaxe, hiponatremia, sinusite, déficit visual, paralisia transitória de nervo craniano, abscesso esfenoidal, meningite, hemorragia no leito do tumor e lesão hipotalâmica. Sendo as três últimas as de maior mortalidade. Neste estudo avaliamos 28 pacientes submetidos à cirurgia de tumor hipofisário via transesfenoidal e 2 por via transcraniana, onde foram observadas as seguintes complicações: fístula liquórica (30%), diabetes insipidus (26,6%) e insuficiência adrenal (13,3%), hemorragia no leito do tumor (6,7%), pneumonia (6,7%) e sinusopatia (3,3%). A taxa de mortalidade foi de 6,7%. Complicações endócrinas podem levar a óbito se não tratadas em tempo hábil. Uma rigorosa avaliação clínica e laboratorial por equipe multidisciplinar é necessária para o bom desempenho no manejo das complicações pós-operatórias dos pacientes submetidos a ressecções de tumor hipofisário, posto que pode antecipar complicações e minimizar seus riscos.

GnRH is a decapeptide hormone, which plays a major role in the process of mammalian reproduction. It is synthesized by the hypothalamus and binds to its cognate receptor on the pituitary, to bring about the release of gonadotropins LH and FSH. The gonadotropin releasing hormone receptor belongs to the family of G-protein coupled receptors that are characterized by the presence of seven putative transmembrane regions linked by extracellular and intracellular loops. It is a glycoprotein made up of 327 amino acids. During the last several years cloning of this receptor from a number of species has provided considerable insight into the molecular basis of interaction between GnRH and its receptor. The GnRH receptor has been cloned and sequenced from a large number of mammalian species such as human, sheep, cow, rat, mouse, etc. GnRH receptor is known to be unique among the G protein coupled receptors by virtue of the fact that it lacks a C terminal tail which has been implicated in coupling to G-proteins in several seven transmembrane domain receptors. Other members of this G-protein coupled receptor family such as the Luetinising hormone receptor, Follicle stimulating hormone receptor contain the characteristic cytoplasmic tail of about 68-72 amino acids, which is believed to possess a plasma membrane targeting signal sequence. Mutation studies carried out revealed that this C terminal sequence may be important in membrane trafficking in other G protein coupled receptors, since mutant forms of the receptor were not expressed on the plasma membrane. In many G-protein coupled receptors, part of the cytoplasmic tail is important for desensitization and internalization. However, the GnRH receptor is an exception in that its G protein coupling and desensitization functions are dependent on regions of the GnRH receptor other than the carboxy terminal cytoplasmic domain. It has been well established that binding of GnRH to its cognate receptor induces conformational change and it is suggested that the entire extracellular loop and transmembrane region are involved in binding and signal transduction. It is pertinent to note in this connection, that the use of both polyclonal and monoclonal antibodies has contributed significantly to the understanding of the interactions between ligands and their cognate receptors. Recent studies have established that there are several extrahypothalamic sites of production of GnRH, which include testes, lymphocytes, human placenta, mammary gland etc. Of these the production of GnRH in the human placenta has attracted attention in view of the demonstration that the placental chorionic gonadotropin production (CG) is regulated by placental GnRH. Our laboratory has been investigating the role of GnRH in regulation of Chorionic Gonadotropin (CG) using both in vitro human placental villi system and pregnant bonnet monkey as models. One important and interesting observation that has been made in our studies as well as by several others is that the affinity of the placental GnRH receptor to its ligand is quite low compared to the pituitary receptor. Available evidence indicates that the hypothalamic and the placental GnRH are similar in structure and consequently the difference in the affinity could be attributed to the differences between the pituitary and the placental GnRH receptor. Considering this, it will be ideal and of interest to compare the GnRH receptor from the pituitary and placenta of a species in which both in vitro and in vivo studies can be carried out. For obvious ethical reasons, in vivo studies cannot be carried out with humans. Since very little information is available on the GnRH receptor in non-human primates, as a first step we undertook the task of characterizing the GnRH receptor from the bonnet monkey pituitary and production of antibodies to it, since all the studies carried out so far with antibodies to GnRH receptor have employed antibodies generated to a small stretch of peptide in the extracellular region. Thus the objective of the present study is to clone and express the GnRH receptor from the pituitary of the bonnet monkey {Macaco radiata), raise antibodies and to characterize them functionally. Chapter 1 provides a general review of information currently available regarding structure of GnRH and its receptor as well as the results of studies using antibodies directed to the GnRH receptor fragments. Chapter 2 deals with the partial cloning of the GnRH receptor from the pituitary of the bonnet monkeys by the technique of RT-PCR. We were able to amplify a PCR fragment of 959bp corresponding to the almost full-length GnRH receptor sequence. Southern blot analysis using the full length human pituitary GnRH receptor cDNA as the probe revealed that the 959 bp product was able to hybridize to the probe, confirming the authenticity of the PCR product. Restriction mapping with three different restriction enzymes also gave the expected pattern. Additional evidence was obtained by cloning of this PCR product into expression vector pGEX 5X-2 and sequencing a number of clones. The sequences obtained were then subjected to homology search with other known GnRH receptor sequences available in the Genebank. The sequence was found to be 97% homologous to the human pituitary GnRH receptor sequence and also showed a high degree of homology with the GnRH receptor from other species. Although antibodies have been raised to the GnRH receptor by immunizing rabbits with synthetic peptides corresponding to extracellular regions of the receptor, most of the antibodies have a very low affinity towards the native receptor. Also results of studies using these antibodies indicated that the peptide antibodies failed to recognize the native receptor. Initially we made efforts to express the full-length receptor in E.coli BL21 cells. However, since we were not successful in our attempts to express the full length, we resorted to express a smaller fragment which corresponded to amino acids 164-266, that encompassed one extracellular, two transmembrane and one intracellular domain. Before we proceeded ahead to express this fragment, the authenticity of this fragment was established by southern hybridization, restriction mapping as well as sequencing. This monkey pituitary GnRH receptor fragment corresponding to 315 bp was cloned in the expression vector pGEX 5X-2 and the protein corresponding to this region was overexpressed as a recombinant fusion protein in E.coli. BL21 plys S strain. Overexpression of the protein was induced using IPTG and the lysate was subjected to electrophoresis on a SDS-PAGE gel A signal corresponding to 37Kda, which is in agreement with the expected size (GST portion of the fusion protein plus the peptide) was observed following induction with IPTG. The overexpressed protein was found to be localized to the inclusion bodies, and this was purified from inclusion bodies by cutting out the band corresponding to the overexpressed protein from the preparative SDS-PAGE gels and the protein was eluted out by electroelution. Sera from the rabbits, which were immunized with the overexpressed protein, were checked for the presence of antibodies by ELISA, using the purified protein as the antigen. After ascertaining the presence of high titre antibodies in the sera of immunized animals, the serum was used to detect the presence of GnRH receptor in the membrane preparations from rat pituitary, monkey pituitary and human placenta using the technique of western blotting. A signal corresponding to 68Kda was found in all the cases and the specificity of this signal was established by preabsorption of the antisemrn with pituitary and placental membrane preparations, which resulted in decrease in the intensity of the signal. . The antiserum was also used to localize the GnRH receptor in different tissues such as first trimester and term human placenta, sheep pituitary, monkey placenta, human pituitary and rat prostate by the technique of immunotlourescence using the confocal microscope. The results of the above studies are presented in Chapter 3. Chapter 4 deals with the functional studies carried out using the antiserum to GnRH receptor in an in vivo system using male and female rats. As discussed earlier, all the reported studies on use of antibodies to GnRH receptor have employed a small region of the extracellular portion of the receptor for the production of antibodies. However, the antibodies in the present study have been directed towards a larger fragment, and considering this, it was of interest to evaluate the effect of these antibodies in in vivo as well as in vitro systems. Two approaches were used to evaluate the effect of antibodies, namely passive and active immunization i.e. administration of antiserum to GnRH receptor fragment raised in rabbits and also immunization with the overexpressed recombinant GnRH receptor protein. This study was carried out in both immature as well as adult male rats and also in the cycling female rats. Several parameters were monitored, which included various androgen dependent parameters in the male reproductive tissue i.e. body weight, testes weight as well as the weight of accessory sex organ-the prostate and also the fertility status. In the female rats the changes in the weight of the ovary, uterus, serum E2 and P4 were monitored. No effect on the body weight, testis weight or prostate weight was noticed in the treated animals compared to the controls. Furthermore, an indication that the hypothalamo-pituitary-gonadal axis was not compromised in the passively immunized animals was obtained from the observation that there was no decrease in the serum and testicular testosterone levels. In fact, there was a significant increase in the serum and testicular testosterone levels. This suggested the possibility that the antibodies are exerting a ßßstimulatory effect. To ascertain this possibility, two androgen dependent parameters namely the levels of mRNA for TGF ß, which is androgen repressed gene and Prostatein Cl, which is an androgen induced gene were monitored. It was observed that there was a significant increase in the steady state mRNA level of Prostatein Cl in GnRH antiserum treated animals and a corresponding decrease in TGFß mRNA levels. Active immunization study with injection of the recombinant protein was also carried out in adult male rats. All immunized animals responded to the immunization by producing high titre antibodies, the presence of which was detected by ELISA using the recombinant protein as the antigen. The results of the study revealed that there was no change in the body weight, testis weight or prostate weight. However, there was a significant increase in the serum and testicular testosterone levels compared to the control animals. Fertility studies indicated that all the animals were fertile. However, as in the case of passive immunization studies, an increase in the mRNA levels of Prostatein Cl was noted although the level of TGFß, which is an androgen repressed gene could not be monitored in this case due to the very high levels of endogenous androgens present in these animals. Thus it appears that the antibodies produced both in rabbits as well as in rats were stimulatory in nature probably indicating some specific characteristic of the region of the receptor to which the antibody has been raised. The results obtained in the present study are of significance considering the fact that studies using the antibodies to LH receptor and TSH receptor, both of which belong to the G-protein coupled family also report production of stimulatory antibodies. Active immunization studies using the GnRH receptor protein in the female rats also revealed that the antibodies were not compromising the hypothalamo-pituitary-gonadal axis. Accordingly, there was no decrease in the serum or ovarian levels of estradiol 17ß and progesterone and there was no difference in the ovarian weight. However, a significant decrease in the uterine weight and difference in the histology of the uterus of the immunized animals was observed. This is of significance, considering the fact that the presence of the GnRH receptor has been reported in the uterus also. In an attempt to develop an in vitro system to monitor the effect of GnRH receptor antibody, an in vitro incubation system with the human placental villi, which is known to produce both GnRH and hCG was standardized. Sensitive ELISA and RIA were developed for GnRH and hCG, respectively to monitor their levels.The results of the studies on the effect of addition of GnRH receptor antibody to the immunoreactive hCG levels in the placental incubation medium are presented in Chapter 5. In addition, advantage was taken of the report of the presence of the specific receptors for GnRH in the Leydig cells of the rats, to evaluate the effect of the GnRH receptor antibodies on the function of leydig cells. Results of studies in which the effect of addition of GnRH receptor antibodies on the testosterone production by purified rat Leydig cells were monitored revealed that there was no inhibitory effect. Finally in the Chapter 6, a general discussion and critical evaluation of the results obtained in the study, in light of similar studies reported in literature are presented.

The hypothalamic-pituitary-thyroid axis operates to maintain the circulating concentration of thyroid hormones. Thyrotropin releasing hormone (TRH) is the major hypothalamic messenger controlling the pituitary-thyroid unit. However, the pituitary-thyroid unit responses to various modalities of TRH exposure are not well characterized. Also, interactions between the thyroid axis and other mammalian organ systems, specifically other hormone axes, to maintain the organism's homeostatic state are not well characterized. This work was designed to clarify the response of the pituitary-thyroid unit to TRH and to assess the effects of physiological levels of the rat's primary adrenal cortical hormone, corticosterone, on the thyroid axis. Adult rats were given equal amounts of TRH by intravenous (I.V.) bolus injection or constant intraperitoneal (I.P.) infusion. Both methods resulted in significant increases in plasma thyroid stimulating hormone (TSH), although the time course and peak plasma value varied with the TRH dosage and administration method. Despite the differences in plasma TSH elicited, the thyroid gland responses were similar. Thus, the pituitary is sensitive to the rate and dose of TRH administration. Also, the thyroid is sensitive to plasma levels of TSH but reaches maximum stimulation at submaximal circulating TSH levels. Adrenalectomized female rats, with I.P. and I.V. catheters, were infused with corticosterone (B) to achieve plasma levels within the rat's physiological range. Plasma samples were drawn before and after submaximal TRH (250 ng/100 g Body Weight) administration for assay of TSH and B concentrations. B in the lower half of its physiological range significantly inhibited the increase in plasma TSH observed 10 and 30 minutes after TRH administration. Also, direct stereotaxic infusion of B (50 ng) followed by TRH (1 ng) into the anterior pituitary inhibited the observed increase in plasma TSH. These studies indicate that homeostatic thyroid axis hormone concentrations are maintained by a feedback loop mechanism which is modulated by adrenal hormones. Specifically, physiological levels of corticosterone decrease pituitary sensitivity to TRH in the rat. In addition, the pituitary and thyroid gland exhibit different response patterns to hormonal stimulation.

Diss. (sammanfattning) Uppsala : Univ., 2002. / Härtill 5 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2005. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2006. / Härtill 4 uppsatser.

Thesis (Ph. D.)--West Virginia University, 2005. / Title from document title page. Document formatted into pages; contains viii, 179 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 156-179).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1940. / Typescript. Includes abstract and vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 180-182).

L’antéhypohyse est une glande endocrine maitresse produisant 6 hormones (GH, TSH, ACTH, PRL, FSH et LH) qui régulent des processus vitaux comme la croissance. Chez l’Homme, des mutations des gènes impliqués dans l’ontogénèse pituitaire sont responsables de déficit(s) isolé (IGHD) ou multiples (CPHD) en hormones antéhypophysaires, pouvant être syndromique(s). L’incidence de ces déficits est d’environ 1/8000 naissances. A ce jour, des mutations rapportées dans une trentaine de gènes permettent d’expliquer cette affection chez seulement 25% des patients. Le premier objectif de ce travail de thèse était d’identifier de nouveaux gènes responsables de déficit antéhypophysaire par une approche « gènes candidats », et par des analyses d’exome couplées à une cartographie par homozygotie. Nous avons pu mettre en évidence des variations dans les gènes NOG, VAX1 et GSX1, impliqués dans l’ontogénèse pituitaire murine, et identifier d’autres gènes potentiellement clés dans le développement de l’hypophyse. L’autre objectif était de caractériser la fonction de LHX4, GHRHR, GLI2 et GSX1 à travers l’étude fonctionnelle des variants identifiés au laboratoire. L’implication de nouveaux variants génétiques de LHX4, GHRHR et GLI2 a permis de préciser le spectre phénotypique associé aux mutations de chacun de ces gènes, et aussi de préciser le rôle de LHX4 dans le réseau moléculaire complexe nécessaire à la formation de l’hypophyse. La compréhension des mécanismes moléculaires à l’origine du développement pituitaire devrait permettre à terme une meilleure prise en charge de cette pathologie très hétérogène, incluant le conseil génétique des familles concernées et le traitement des patients. / The anterior pituitary is a master endocrine gland producing 6 hormones (GH, TSH, ACTH, PRL, FSH and LH) that regulate essential life processes such as growth. In the human, mutations in genes encoding morphogenes and transcription factors implicated in pituitary ontogenesis are responsible for isolated (IGHD) or combined (CPHD) pituitary hormone deficit(s) that can be syndromic. The incidence of those deficits is close to 1/8,000 births. So far, mutations reported in about thirty genes explain only 25% of the cases. The first goal of this thesis was to identify new genes responsible for pituitary hormone deficits through a candidate gene approach, and by whole-exome sequencing coupled with homozygosity mapping, using a large cohort of more than 3000 DNA samples collected by the laboratory since 1997.We found variations in NOG, VAX1 and GSX1 genes, all involved in mouse pituitary ontogenesis, and we identified potentially key genes for pituitary developpment.The other aim of this work was to characterize the function of LHX4, GHRHR, GLI2 and GSX1 through the functional evaluation of the variants identified in the laboratory. The implication of new disease-causing genetic variants in LHX4, GHRHR and GLI2 allowed us to delineate the phenotypic spectrum associated with mutations for each gene, and also to precise the role of LHX4 in the complex molecular network required for proper pituitary development. A better understanding of the molecular mecanisms involved in pituitary formation should lead to new ways for management of this heterogenous condition, including genetic counseling and therapeutic decisions in affected families.

京都大学 / 新制・論文博士 / 博士(医学) / 乙第13419号 / 論医博第2227号 / 新制||医||1052(附属図書館) / 京都大学大学院医学研究科脳統御医科学系専攻 / (主査)教授 高橋 淳, 教授 中本 裕士, 教授 大森 孝一 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM