Autocrine regulation of gonadotropin-releasing hormone in immortalized hypothalamic GT1-7 neurons

 

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dc.contributor.advisor Millar, Robert P en_ZA
dc.contributor.advisor Dutlow, Clive en_ZA
dc.contributor.author Pithey, Anne Louise en_ZA
dc.date.accessioned 2018-01-29T06:45:49Z
dc.date.available 2018-01-29T06:45:49Z
dc.date.issued 1994 en_ZA
dc.identifier.citation Pithey, A. 1994. Autocrine regulation of gonadotropin-releasing hormone in immortalized hypothalamic GT1-7 neurons. University of Cape Town. en_ZA
dc.identifier.uri http://hdl.handle.net/11427/27030
dc.description.abstract The existence of an ultrashort feedback mechanism regulating GnRH secretion has been supported from in vivo and in vitro studies. However, the complex synaptic connections of GnRH neurons with other neural elements made it difficult to determine whether the regulation was mediated by direct actions on the GnRH neurons or through actions on other interneurons. The recent development of the GnRH-secreting neuronal cell line, GT1, provided a model system for the study of neural regulation of a pure population of GnRH neurons. The present studies utilized GT1 -7 cells to investigate whether GnRH (at the level of the nerve terminal) influences the control of its own release. Preliminary studies determined the presence of GnRH mRNA in GT1-7 cells and established a cell culture system for the analysis of secretagogue-induced GnRH release. In this system GnRH release was shown to be spontaneous and was enhanced by the addition of K⁺, L-GLU, forskolin and PMA. Furthermore, K⁺- and forskolin-induced GnRH release was dependent on extracellular Ca²⁺. For the analysis of an ultrashort feedback mechanism, GT1-7 cells were cultured in 6-well plates to near confluence and then incubated in serum-free medium in the presence (1 nM- 1 μM) or absence of GnRH antagonist, Ant 27. Basal, K⁺-and forskolin-induced secretion of GnRH was monitored with antiserum 1076 which does not cross-react with Ant 27 at> 1 μM. Ant 27 treatment increased basal, K⁺- and forskolin-stimulated GnRH release in a dose-dependent manner. Total content was unaffected by 18 h treatment of GT1-7 cells with Ant 27. This suggests that the effects of Ant 27 are at the level of release and not biosynthesis. The presence of GnRH binding sites in the cells was demonstrated with ¹²⁵I-GnRH analog. These findings support the concept that GnRH, acting via autoreceptors, negatively controls its own release. en_ZA
dc.language.iso eng en_ZA
dc.subject.other Chemical Pathology en_ZA
dc.subject.other Autocrine Motility Factor en_ZA
dc.subject.other Gonadorelin en_ZA
dc.subject.other Receptors, LHRH en_ZA
dc.title Autocrine regulation of gonadotropin-releasing hormone in immortalized hypothalamic GT1-7 neurons en_ZA
dc.type Master Thesis
uct.type.publication Research en_ZA
uct.type.resource Thesis en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Health Sciences en_ZA
dc.publisher.department Division of Chemical Pathology en_ZA
dc.type.qualificationlevel Masters
dc.type.qualificationname MSc (Med) en_ZA
uct.type.filetype Text
uct.type.filetype Image
dc.identifier.apacitation Pithey, A. L. (1994). <i>Autocrine regulation of gonadotropin-releasing hormone in immortalized hypothalamic GT1-7 neurons</i>. (Thesis). University of Cape Town ,Faculty of Health Sciences ,Division of Chemical Pathology. Retrieved from http://hdl.handle.net/11427/27030 en_ZA
dc.identifier.chicagocitation Pithey, Anne Louise. <i>"Autocrine regulation of gonadotropin-releasing hormone in immortalized hypothalamic GT1-7 neurons."</i> Thesis., University of Cape Town ,Faculty of Health Sciences ,Division of Chemical Pathology, 1994. http://hdl.handle.net/11427/27030 en_ZA
dc.identifier.vancouvercitation Pithey AL. Autocrine regulation of gonadotropin-releasing hormone in immortalized hypothalamic GT1-7 neurons. [Thesis]. University of Cape Town ,Faculty of Health Sciences ,Division of Chemical Pathology, 1994 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/27030 en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Pithey, Anne Louise AB - The existence of an ultrashort feedback mechanism regulating GnRH secretion has been supported from in vivo and in vitro studies. However, the complex synaptic connections of GnRH neurons with other neural elements made it difficult to determine whether the regulation was mediated by direct actions on the GnRH neurons or through actions on other interneurons. The recent development of the GnRH-secreting neuronal cell line, GT1, provided a model system for the study of neural regulation of a pure population of GnRH neurons. The present studies utilized GT1 -7 cells to investigate whether GnRH (at the level of the nerve terminal) influences the control of its own release. Preliminary studies determined the presence of GnRH mRNA in GT1-7 cells and established a cell culture system for the analysis of secretagogue-induced GnRH release. In this system GnRH release was shown to be spontaneous and was enhanced by the addition of K⁺, L-GLU, forskolin and PMA. Furthermore, K⁺- and forskolin-induced GnRH release was dependent on extracellular Ca²⁺. For the analysis of an ultrashort feedback mechanism, GT1-7 cells were cultured in 6-well plates to near confluence and then incubated in serum-free medium in the presence (1 nM- 1 μM) or absence of GnRH antagonist, Ant 27. Basal, K⁺-and forskolin-induced secretion of GnRH was monitored with antiserum 1076 which does not cross-react with Ant 27 at> 1 μM. Ant 27 treatment increased basal, K⁺- and forskolin-stimulated GnRH release in a dose-dependent manner. Total content was unaffected by 18 h treatment of GT1-7 cells with Ant 27. This suggests that the effects of Ant 27 are at the level of release and not biosynthesis. The presence of GnRH binding sites in the cells was demonstrated with ¹²⁵I-GnRH analog. These findings support the concept that GnRH, acting via autoreceptors, negatively controls its own release. DA - 1994 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1994 T1 - Autocrine regulation of gonadotropin-releasing hormone in immortalized hypothalamic GT1-7 neurons TI - Autocrine regulation of gonadotropin-releasing hormone in immortalized hypothalamic GT1-7 neurons UR - http://hdl.handle.net/11427/27030 ER - en_ZA


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