Fung Chun Kit. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 117-139). / Abstracts in English and Chinese. / Declaration of Originality --- p.i / Acknowledgements --- p.ii / Abstract --- p.iii / 摘要 --- p.v / List of figures --- p.vi / List of tables --- p.viii / List of abbreviations --- p.ix / Chapter Chapter I --- General introduction --- p.1 / Chapter 1.1 --- Different fish habitats with various salinities --- p.1 / Chapter 1.2 --- Osmotic challenges faced by teleosts --- p.2 / Chapter 1.3 --- High ionic strength results in DNA damage and excess water gain --- p.3 / Chapter 1.4 --- Osmoregulatory organs and mechanisms for osmotic balance --- p.4 / Chapter 1.5 --- Different tolerance to salinity changes --- p.8 / Chapter 1.6 --- Effective communication among osmoregulatory organs --- p.9 / Chapter 1.7 --- Introduction to GH and PRL --- p.9 / Chapter 1.8 --- Structure of the GHR and PRLR --- p.10 / Chapter 1.9 --- Hypoosmoregulatory action of GH/IGF-I axis in teleosts --- p.11 / Chapter 1.10 --- Hyperosmoregulatory action of PRL in teleosts --- p.11 / Chapter Chapter II --- Research rationale --- p.13 / Chapter 2.1 --- Physiological importance of osmoregulation in fish --- p.13 / Chapter 2.1.1 --- Energy metabolism --- p.13 / Chapter 2.1.2 --- Growth --- p.14 / Chapter 2.1.3 --- Immunity --- p.14 / Chapter 2.1.4 --- Reproduction --- p.15 / Chapter 2.2 --- Aquaculture importance --- p.15 / Chapter 2.3 --- Unknown molecular regulatory mechanism of hormones during salinity changes in fish --- p.16 / Chapter 2.4 --- Animal model --- p.17 / Chapter Chapter III --- In vivo studies of sbGHR and sbPRLR expression in osmoregulatory organs in response to salinity changes --- p.18 / Chapter 3.1 --- Introduction --- p.18 / Chapter 3.1.1 --- Dynamic change of GH level during salinity changes --- p.18 / Chapter 3.1.2 --- Dynamic change of PRL level during salinity changes --- p.19 / Chapter 3.1.3 --- In vitro studies of GH and PRL release from teleost pituitary in response to extracellular osmolality changes --- p.20 / Chapter 3.1.4 --- Biological actions of GH and PRL through the GHR and PRLR --- p.21 / Chapter 3.2 --- Materials and methods --- p.23 / Chapter 3.3 --- Results --- p.28 / Chapter 3.4 --- Discussion --- p.36 / Chapter 3.4.1 --- Plasma osmolality change during salinity changes --- p.36 / Chapter 3.4.2 --- Gene expression after HSW exposure --- p.38 / Chapter 3.4.3 --- Ionic mediators of the gene expression --- p.43 / Chapter 3.4.4 --- Gene expression after BW exposure --- p.44 / Chapter 3.4.5 --- Dynamic changes of the GHR and PRLR in response to salinity changes --- p.45 / Chapter 3.4.6 --- Regulation of the gene expression in response to salinity changes --- p.46 / Chapter Chapter IV --- Gene expression of sbGHR in liver during salinity changes --- p.49 / Chapter 4.1 --- Introduction --- p.49 / Chapter 4.1.1 --- Responses of the somatotropic axis to salinity changes in fish --- p.49 / Chapter 4.2 --- Materials and methods --- p.52 / Chapter 4.3 --- Results --- p.56 / Chapter 4.4 --- Discussion --- p.60 / Chapter 4.4.1 --- Inhibition of GHR and IGF-I gene expression in liver during HSW exposure --- p.60 / Chapter 4.4.2 --- Downregulation of GHR gene expression by hyperosmotic stress --- p.62 / Chapter 4.4.3 --- Growth retardation of fish during hyperosmotic environment --- p.64 / Chapter Chapter V --- Gene expression studies of sbPRLR in gill organ culture --- p.68 / Chapter 5.1 --- Introduction --- p.68 / Chapter 5.1.1 --- Functions of gill in fish osmoregulation --- p.68 / Chapter 5.1.2 --- Gill culture as a model for osmoregulation studies --- p.69 / Chapter 5.2 --- Materials and methods --- p.70 / Chapter 5.3 --- Results --- p.71 / Chapter 5.4 --- Discussion --- p.73 / Chapter Chapter VI --- Regulation of gene expression of sbGHR in liver during hyperosmotic stress: promoter studies --- p.75 / Chapter 6.1 --- Introduction --- p.75 / Chapter 6.1.1 --- What is a promoter? --- p.75 / Chapter 6.1.2 --- Promoter studies of GHR gene --- p.76 / Chapter 6.2 --- Materials and methods --- p.78 / Chapter 6.3 --- Results --- p.85 / Chapter 6.4 --- Discussion --- p.104 / Chapter Chapter VII --- General discussion and future perspectives --- p.111 / References --- p.117