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dc.contributor.advisorThe aim of the studies described in this thesis was to investigate whether 1. LHRH (luteinizing-hormone-releasing hormone) modulates hCG release from the syncytiotrophoblast through the mediation of specific receptors and 2. chronic exposure to native LHRH or its more potent agonist (D-ser-t-bu(6) des-Gly-NH(2)(10)) LHRH ethylamide leads to a reduction in hCG output.en
dc.contributor.advisorTo examine tissue for the presence of specific LHRH receptors l,000g, 10,000g and 100,000g preparations of placental tissue from both term and 8-12 weeks gestation were incubated with mono-iodinated LHRH agonist and increasing concentrations of cold LHRH agonist. Specific binding sites were shown to be present (Ka=5x10^M(-1) both on normal tissue and on hydatidiform mole. LHRH had the same affinity for the receptors in these tissues as the agonist.en
dc.contributor.advisorTo determine whether the low affinity of the receptor was due to degradation of the ligands, binding studies were carried out in the presence of enzyme inhibitors. Contrary to expectation the inhibitors decreased binding but did not increase the affinity. It appeared that thiol and serine inhibitors blocked binding while carboxyl inhibitors showed no effect. An enzyme substrate L-leucine β-naphthylamine inhibited binding but when leucine and naphthylamine were examined, naphthylamine alone reduced binding.en
dc.contributor.advisorDegradation of native and agonist LHRH were compared and, as in other tissues, the agonist was more resistant to degradation than native LHRH.en
dc.contributor.advisorThe effect of LHRH and the agonist on hCG production by cultures of explants of 12 week trophoblastic tissue was studied during 5 days of culture. No consistent stimulation of hCG secretion could be demonstrated. Culture of term placental villi for 5 days showed no overall synthesis of hCG and daily hCG secretion declined in a similar manner to that shown by Siler-Khodr & Khodr (1979). Electron microscopic studies of the term placental villi showed considerable changes in morphology during culture. After only 1 day in culture the nuclei were densely stained and the microvilli were no longer present and while after 2 days the syncytium was becoming detached from the basement membrane. During the following days of culture there was further deterioration of the tissue.en
dc.contributor.advisorTo overcome the problem of tissue viability a second method of culture was adopted. Minced chorionic villi or collagenase dispersed cells were supported in Biogel columns and perfused with medium. Hormones released in response to LHRH and its agonist were measured in fractions collected every five minutes. With minced tissue LHRH released more peaks of hCG than did the control (x(2):p<0.05). However 80% of pulses resulted in no significant increase in hCG release.en
dc.contributor.advisorThe results suggested that although the presence of both LHRH-like factors and specific LHRH receptors in the placenta have been reported, LHRH does not appear to play a major role in the regulation of hCG production by the placenta.en
dc.contributor.authorCurrie, Aileen Janeen
dc.date.accessioned2018-01-31T11:19:37Z
dc.date.available2018-01-31T11:19:37Z
dc.date.issued1983
dc.identifier.urihttp://hdl.handle.net/1842/26423
dc.description.abstracten
dc.publisherThe University of Edinburghen
dc.relation.ispartofAnnexe Thesis Digitisation Project 2017 Block 15en
dc.relation.isreferencedbyAlready catalogueden
dc.titleInvestigations into the role of LHRH in the regulation of hCG release by the human placentaen
dc.typeThesis or Dissertationen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnamePhD Doctor of Philosophyen


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