Show simple item record

dc.contributor.authorShale, J. A.en
dc.date.accessioned2018-01-31T11:24:35Z
dc.date.available2018-01-31T11:24:35Z
dc.date.issued1998en
dc.identifier.urihttp://hdl.handle.net/1842/26925
dc.description.abstracten
dc.description.abstractIn birds, prolactin secretion is stimulated by a hypothalamic prolactin releasing hormone, vasoactive intestinal polypeptide (VIP). Active immunization against VIP suppresses both prolactin and LH secretion. Since VIP in physiological doses, does not stimulate LH release, it is suggested that it might act to regulate the function of LHproducing cells in a paracrine manner. The aim of this thesis is to provide biochemical, molecular and anatomical evidence to support this hypothesis.en
dc.description.abstractVasoactive intestinal polypeptide was shown to be present in the chicken anterior pituitary gland using high performance liquid chromatography (HPLC), radioimmunoassay (RIA) and immunocytochemistry. The VIP antibodies used for both RIA and immunocytochemistry showed no cross reaction with any known VIP-like peptides, including pituitary adenylate cyclase activating polypeptide (PACAP). VIP mRNA was also shown to be present in anterior pituitary gland, using reversetranscription polymerase chain reaction (RT-PCR) and primers designed from the chicken VIP cDNA sequence, and by solution hybridization RNAse protection assay.en
dc.description.abstractTwo VIP-immunoreactive cell (VIP-ir) types were found throughout the cephalic and caudal lobes of the anterior pituitary gland. The morphological features of the VIP-ir cell types were similar to that of the folliculo-stellate cell type (FS-cell). One VIP-cell type contained the Ca 2+ binding protein S-100 protein, a specific marker of FS-cells, while the S-100 protein was not detected in the second VIP-cell type. The VIP-cells were closely associated with gonadotrophs, lactotrophs and unidentified cell types, but VIP-ir was not colocalised with LH or PRL. The VIP-cell characteristically enveloped several adjacent gonadotrophs with cytoplasmic projections, which suggests that intra-pituitary VIP may regulate the gonadotroph in a paracrine manner.en
dc.description.abstractVIP receptors were localised immunocytochemically, in the anterior pituitary gland and hypothalamus, using antibodies raised the peptide sequence of the human subtype-I (VIP-RI) and the subtype-II VIP receptors (VIP-RII). The VIP-RI was not present in PRL-, LH- or GH-cells, but was found exclusively in ACTH-cells. The VIP-RII was diffusely distributed through both lobes of the chicken anterior pituitary gland, but the cell type containing VIP-RII immunoreactivity was not identified.en
dc.description.abstractThe effects of VIP and PACAP on pituitary hormone secretion were determined in vitro using cultured hemi-pituitaries. VIP and PACAP stimulated PRL secretion in a dose dependent manner. High concentrations of VIP and PACAP stimulated GH and LH secretion but did not affect ACTH secretion.en
dc.description.abstractIn conclusion, VIP is produced in the anterior pituitary gland and occurs in a FS-cell type which is closely associated with gonadotrophs. These observations are consistent with the view that intra-pituitary VIP may act in a paracrine manner to regulate the function of gonadotrophs.en
dc.publisherThe University of Edinburghen
dc.relation.ispartofAnnexe Thesis Digitisation Project 2017 Block 15en
dc.relation.isreferencedbyAlready catalogueden
dc.titleVasoactive intestinal polypeptide in the chicken anterior pituitary glanden
dc.typeThesis or Dissertationen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnamePhD Doctor of Philosophyen


Files in this item

This item appears in the following Collection(s)

Show simple item record