Another growth factor candidate is a recently recognized bioactive peptide, islet-neogenesis associated protein (INGAP). A master pancreatic transcription factor, pancreatic duodenal homeobox-1 (Pdx-1), was overexpressed in PSCs by the adenovirus-mediated transfer method in the present study. With the infection of adenovirus expressing Pdx-1, several beta-cell developmental genes, including Isl-1, Beta2, Nkx2.2, Nkx6.1 and the endogenous Pdx-1 were found to be upregulated temporally in our PSCs-derived ICCs. Meanwhile, previous study has shown that Pdx-1/INGAP-positive cells represent a new stem cell subpopulation during early stage of pancreatic development. We thus explore whether any functional integration of Pdx-1 and INGAP in the growth and functional maturation of PSCs. In order to achieve this proposition, the effects of over-expressing PSCs with the Pdx-1 adenovirus in conjunction with the treatment of INGAP were then investigated. Interestingly, differentiation of the PSC-derived ICCs was not further enhanced by the synergistic treatment of Pdx-1 and INGAP when compared to those ICCs infected with adenovirus expressing Pdx-1 alone, as revealed by the endogenous Pdx-1 and insulin gene expression and their C-peptide content. These data might provide some clues to the intricate interaction between Pdx-1 and INGAP in regulating the ICC and/or the pancreatic endocrine differentiation. (Abstract shortened by UMI.) / Due to the scarcity of fetal pancreas for generating functional insulin-secreting cell clusters for sufficient islet transplantation, we targeted for searching pancreatic stem/progenitor cells. Putative PSCs can be aggregated and differentiated into islet-like cell clusters (ICCs) when exposed to serum-free medium containing various conventional growth factors, including HGF, GLP-1, betacellulin and nicotinamide. / Fetal pancreatic tissue consisting of immature progenitor cells serves as a potential source of stem cells as they possess a higher replicative capacity and longevity than their adult counterparts. / Two novel candidates and a key pancreatic transcription factor on the PSC/ICC proliferation and differentiation were investigated in the present study. One of them is a ubiquitously expressed multi-PDZ-domain protein, PDZ-domain-containing 2 (PDZD2), which was previously found to express in the mouse beta cells and exhibit mitogenic effects in beta cell line. Results showed that PDZD2 was detected in high levels in both human fetal pancreas and in PSCs. Results indicate the potential involvement of PDZD2 in regulating PSCs proliferation and differentiation and pancreatic development. / Suen Po Man, Ada. / "July 2007." / Adviser: P.S. Leung. / Source: Dissertation Abstracts International, Volume: 69-01, Section: B, page: 0051. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (p. 194-214). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Ma, Man Ting. / "July 2010." / Thesis (M.Phil.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 186-207). / Abstracts in English and Chinese. / Abstract --- p.I / List of Publications --- p.VI / Acknowledgements --- p.VIII / Table of Contents --- p.X / List of Figures --- p.XV / List of Tables --- p.XVIII / List of Abbreviations --- p.XIX / Chapter CHAPTER1 --- INTRODUCTION / Chapter 1.1 --- The Pancreas --- p.2 / Chapter 1.1.1 --- Structure of pancreas --- p.2 / Chapter 1.1.2 --- Structure and function of exocrine pancreas --- p.6 / Chapter 1.1.3 --- Structure and function of endocrine pancreas --- p.9 / Chapter 1.1.3.1 --- Pancreatic islet and islet cells --- p.9 / Chapter 1.1.3.2 --- Glucose-stimulated insulin secretion from islets --- p.12 / Chapter 1.2 --- Type 1 Diabetes Mellitus (T1DM) --- p.14 / Chapter 1.2.1 --- Pathophysiology of Diabetes Mellitus --- p.14 / Chapter 1.2.2 --- Autoimmunity in T1DM --- p.17 / Chapter 1.2.3 --- Management ofTlDM --- p.20 / Chapter 1.2.3.1 --- Insulin replacement --- p.20 / Chapter 1.2.3.2 --- Pancreas and islet transplantation --- p.21 / Chapter 1.2.3.3 --- Stem-cell-based transplantation --- p.22 / Chapter 1.3 --- The Adaptive Immune System --- p.26 / Chapter 1.3.1 --- T-lymphocytes --- p.26 / Chapter 1.3.2 --- B-lymphocytes --- p.29 / Chapter 1.3.3 --- Major histocompatibility complex (MHC) --- p.30 / Chapter 1.3.3.1 --- Classification of MHC molecules --- p.30 / Chapter 1.3.3.2 --- Structure of MHC class I and II molecules --- p.32 / Chapter 1.3.3.3 --- Function and regulation of MHC molecules --- p.34 / Chapter 1.3.4 --- HLA-G and its immuno-modulatory properties --- p.36 / Chapter 1.4 --- Transplantation Rejection --- p.40 / Chapter 1.4.1 --- Mechanisms involved in transplantation rejection --- p.40 / Chapter 1.4.2 --- Immunobiology of rejection --- p.41 / Chapter 1.4.2.1 --- Direct allorecognition pathway --- p.42 / Chapter 1.4.2.2 --- Indirect allorecognition pathway --- p.43 / Chapter 1.4.2.3 --- Semi-direct allorecognition pathway --- p.43 / Chapter 1.4.3 --- Xenotransplantation --- p.46 / Chapter 1.5 --- Cytokines and Immunity --- p.48 / Chapter 1.5.1 --- Interferons --- p.48 / Chapter 1.5.1.1 --- Interferon-γ and its immune regulation --- p.49 / Chapter 1.5.1.2 --- Effect and kinetics of interferon-γ on MHC molecules expression --- p.53 / Chapter 1.5.1.3 --- Regulation of interferon-γ production --- p.56 / Chapter 1.5.2 --- Interlukins --- p.58 / Chapter 1.5.2.1 --- IL-10 and its immune regulation --- p.58 / Chapter 1.5.2.2 --- IL-10 and HLA-G --- p.59 / Chapter 1.6 --- Stem Cells and their Immunogenicity --- p.62 / Chapter 1.6.1 --- Embroynic stem cells --- p.62 / Chapter 1.6.2 --- Mesenchymal stem cells --- p.64 / Chapter 1.6.3 --- Neural stem cells --- p.68 / Chapter 1.6.4 --- Fetal stem cells --- p.69 / Chapter 1.6.5 --- Potential immuno-study in human fetal pancreatic stem cells --- p.70 / Chapter 1.7 --- Aims and Objectives of study --- p.72 / Chapter CHAPTER2 --- MATERIALS AND METHODS / Chapter 2.1 --- Isolation of Pancreatic Progenitors (PPCs) from Human Fetal Pancreas and Induction of Islet-like Cell Cluster (ICCs) Differentiation --- p.75 / Chapter 2.1.1 --- Tissue procurement --- p.75 / Chapter 2.1.2 --- Tissue processing and PPCs culture --- p.75 / Chapter 2.1.3 --- In vitro differentiation of PPCs into ICCs --- p.78 / Chapter 2.1.4 --- Interferon-γ and IL-10 treatment --- p.80 / Chapter 2.2 --- Cell culture of human placental Choriocarcinoma JEG-3 Cell Line --- p.81 / Chapter 2.3 --- RNA Expression Detection --- p.82 / Chapter 2.3.1 --- RNA isolation --- p.82 / Chapter 2.3.2 --- Reverse transcriptase (RT) --- p.83 / Chapter 2.3.3 --- Design of primers for Polymerase Chain Reaction (PCR) and Real-time PCR --- p.84 / Chapter 2.3.4 --- PCR --- p.86 / Chapter 2.3.5 --- Real-time PCR analysis --- p.88 / Chapter 2.3.6 --- Calculation using the comparative CT method --- p.90 / Chapter 2.4 --- Flow Cytometry --- p.91 / Chapter 2.5 --- Western Blotting Analysis --- p.93 / Chapter 2.5.1 --- Protein extraction and quantification --- p.93 / Chapter 2.5.2 --- Western blotting --- p.93 / Chapter 2.6 --- Mixed Lymphocyte Reaction (MLR) --- p.95 / Chapter 2.6.1 --- Isolation of peripheral blood mononuclear cells (PBMCs) --- p.95 / Chapter 2.6.2 --- PPC-PBMCs MLR --- p.98 / Chapter 2.6.3 --- ICC-PBMCs MLR --- p.98 / Chapter 2.6.4 --- Proliferation assay --- p.99 / Chapter 2.7 --- ICC Transplantation --- p.101 / Chapter 2.7.1 --- Streptozotocin-induced diabetic animals for transplantation --- p.101 / Chapter 2.7.2 --- Procedures of ICCs transplantation --- p.102 / Chapter 2.8 --- Histological Analysis of ICC Graft --- p.105 / Chapter 2.8.1 --- H&E staining --- p.105 / Chapter 2.8.2 --- DAB staining --- p.106 / Chapter 2.8.3 --- Immunofluorescence staining --- p.107 / Chapter 2.9 --- Enzyme-linked Immunosorbent Assay (ELISA) --- p.109 / Chapter 2.10 --- Statistical Data Analysis --- p.110 / Chapter CHAPTER3 --- RESULTS / Chapter 3.1 --- Immuno-characterization of PPCs and ICCs --- p.112 / Chapter 3.2 --- Effect of cytokines on immune-properties of PPCs and ICCs --- p.115 / Chapter 3.2.1 --- Effect of lFN-γ on MHC-I expression in PPCs --- p.115 / Chapter 3.2.2 --- Effect of lFN-γ and IL-10 on HLA-G expression in PPCs and ICCs --- p.119 / Chapter 3.2.3 --- Effect of IFN-γ on B7H4 expression in PPCs --- p.123 / Chapter 3.3 --- Comparison of immune-properties of PPCs and ICCs from 1st and 2nd trimester --- p.125 / Chapter 3.3.1 --- Differential expression of MHC molecules in PPCs --- p.125 / Chapter 3.3.2 --- Different immune-related gene expression in PPCs and ICCs --- p.128 / Chapter 3.3.3 --- Comparison of IFN-γ activated MHC molecules expression in PPCs/ICCs --- p.134 / Chapter 3.3.4 --- Comparison of other IFN-γ activated genes expression in PPCs --- p.139 / Chapter 3.4 --- Mixed lymphocyte reaction of PPCs from 1st and 2nd trimester --- p.143 / Chapter 3.4.1 --- Effect of PPCs on proliferation of PBMC --- p.143 / Chapter 3.4.2 --- Effect of ICCs on proliferation of PBMC --- p.145 / Chapter 3.4.3 --- Effect of PPCs on cytokine production in PBMC --- p.149 / Chapter 3.5 --- Xenotransplantation of ICCs into diabetic mouse model --- p.152 / Chapter 3.5.1 --- Blood glucose level of diabetic mice after transplantation --- p.152 / Chapter 3.5.2 --- Histological evaluation of transplanted ICCs grafts --- p.154 / Chapter 3.5.3 --- Infiltration of CD45 into transplanted grafts of 1st and 2nd trimester --- p.158 / Chapter CHAPTER4 --- DISCUSSION / Chapter 4.1 --- Expression of selected immuno-regulated genes in PPCs and ICCs --- p.163 / Chapter 4.2 --- Effect of IFN-g and IL-10 on expression of immuno-regulated genes in PPCs and ICCs --- p.166 / Chapter 4.3 --- In vitro studies on immunogenicity of PPCs and ICCs from first and second trimester --- p.171 / Chapter 4.3.1 --- Immune-related genes expression --- p.171 / Chapter 4.3.2 --- IFN-γ activated gene expression --- p.173 / Chapter 4.3.3 --- Mixed lymphocyte reaction --- p.175 / Chapter 4.3.4 --- Cytokine production of PBMC in MLR --- p.179 / Chapter 4.4 --- In vivo Xenotransplantation of ICCs into diabetic mouse model --- p.181 / Chapter 4.5 --- Conclusion --- p.187 / Chapter 4.6 --- Further studies --- p.188 / Chapter CHAPTER5 --- BIBLIOGRAPHY / Bibliography by Alphabetical Order --- p.189

Ng, Ka Yan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 179-204). / Abstracts in English and Chinese. / Abstract --- p.I / 摘要 --- p.IV / Publications --- p.VII / Acknowledgements --- p.VIII / Table of contents --- p.IX / List of figures --- p.XV / List of tables --- p.XVII / List of abbreviations --- p.XVIII / Chapter Chapter 1 --- General Introduction / Chapter 1.1 --- The Pancreas --- p.2 / Chapter 1.1.1 --- Anatomy of Pancreas --- p.2 / Chapter 1.1.2 --- The Exocrine Pancreas --- p.4 / Chapter 1.1.3 --- The Endocrine Pancreas --- p.5 / Chapter 1.1.3.1 --- Structure of Islets --- p.5 / Chapter 1.1.3.2 --- "Functions of α-, β-, y-, ð-, Σ-and PP-cells in Islets" --- p.7 / Chapter 1.1.4 --- Overview of Pancreas Development --- p.9 / Chapter 1.1.4.1 --- Organ Morphology --- p.10 / Chapter 1.1.4.2 --- Cyto-differentiation --- p.12 / Chapter 1.1.4.3 --- Control by Transcriptional Factors --- p.14 / Chapter 1.1.5 --- Postnatal Pancreas Development and Regeneration --- p.18 / Chapter 1.1.5.1 --- Proliferation of Pre-existing β-cells --- p.19 / Chapter 1.1.5.2 --- Neogenesis from Precursor Cells --- p.20 / Chapter 1.1.5.3 --- Transdifferentiation of other Cells --- p.20 / Chapter 1.2 --- Diabetes Mellitus --- p.22 / Chapter 1.2.1 --- Pathophysiology of Diabetes Mellitus and Current Treatments --- p.24 / Chapter 1.2.1.1 --- Type I Diabetes Mellitus --- p.24 / Chapter 1.2.1.2 --- Type II Diabetes Mellitus --- p.25 / Chapter 1.2.1.3 --- Gestational Diabetes --- p.27 / Chapter 1.2.1.4 --- Secondary Diabetes --- p.28 / Chapter 1.3 --- Stem Cell therapy --- p.29 / Chapter 1.3.1 --- Stem Cell --- p.29 / Chapter 1.3.1.1 --- Mesenchymal Stem Sell --- p.31 / Chapter 1.3.1.2 --- Embryonic Stem Cell --- p.35 / Chapter 1.3.1.3 --- Induced Pluripotent Stem Cell --- p.36 / Chapter 1.3.2 --- Islets Engineering --- p.37 / Chapter 1.3.2.1 --- Genetic Modification --- p.37 / Chapter 1.3.2.2 --- Directed Differentiation --- p.38 / Chapter 1.3.2.3 --- Microenvironment --- p.38 / Chapter 1.3.2.4 --- In vivo Regeneration --- p.39 / Chapter 1.3.2.5 --- Cell Fusions --- p.40 / Chapter 1.3.2.6 --- Combinatory Treatments --- p.40 / Chapter 1.4 --- The Vitamin A & Vitamin D System --- p.42 / Chapter 1.4.1 --- The Vitamin A --- p.42 / Chapter 1.4.2 --- Vitamin A Metabolism --- p.44 / Chapter 1.4.3 --- Roles of vitamin A in Pancreatic Development --- p.46 / Chapter 1.4.4 --- The Vitamin D --- p.48 / Chapter 1.4.5 --- Vitamin D Metabolism --- p.49 / Chapter 1.4.6 --- Metabolic Functions of Vitamin D in Islets --- p.51 / Chapter 1.4.7 --- Cod Liver Oil --- p.53 / Chapter 1.4.8 --- Interactions between Vitamin A and Vitamin D --- p.53 / Chapter 1.5 --- The Relations of Liver and Pancreas Development --- p.55 / Chapter 1.5.1 --- Endoderm Induction for Hepatic and Pancreatic Differentiation of ESCs --- p.55 / Chapter 1.5.2 --- Bipotential Precursor Population within Embryonic Endoderm --- p.56 / Chapter 1.5.3 --- Pancreatic Islets Promote Mature Liver Hepatocytes Proliferation --- p.57 / Chapter 1.5.4 --- Transdifferentiation --- p.57 / Chapter 1.5.5 --- Transplantation in Liver Niche Promotes Maturation of Insulin-Producing Cells --- p.60 / Chapter 1.5.6 --- Neuronal Relay from the Liver to Pancreatic --- p.61 / Chapter 1.5.7 --- Development of Islets in the Nile Tilapia --- p.62 / Chapter 1.6 --- The Insulin-like Growth Factor-I (IGF1) --- p.64 / Chapter 1.6.1 --- IGF1 System --- p.64 / Chapter 1.6.2 --- IGF 1 Regulation --- p.65 / Chapter 1.6.3 --- Roles of IGF 1 in Pancreatic Development and Regeneration --- p.68 / Chapter 1.7 --- Aims and Objectives of Study --- p.70 / Chapter Chapter 2 --- General Materials and Methods / Chapter 2.1 --- Pancreatic progenitor cells (PPCs) and liver stromal cells (LSCs) isolation and cell culture --- p.72 / Chapter 2.1.1 --- Tissue procurement --- p.72 / Chapter 2.1.2 --- PPC and LSC culture --- p.72 / Chapter 2.1.3 --- "Treatments of vitamin A, vitamin D and IGF 1" --- p.76 / Chapter 2.1.4 --- "Cell culture of Caco-2, HepG2 and DU-145" --- p.76 / Chapter 2.2 --- Induction of Islet-like Cell Clusters (ICCs) Differentiation --- p.77 / Chapter 2.2.1 --- In vitro Directed Differentiation --- p.77 / Chapter 2.2.2 --- In vitro LSC Microenvironment --- p.77 / Chapter 2.3 --- RNA Expression Detection --- p.79 / Chapter 2.3.1 --- RNA isolation --- p.79 / Chapter 2.3.2 --- Reverse Transcription --- p.79 / Chapter 2.3.3 --- Polymerase Chain Reaction (PCR) --- p.80 / Chapter 2.3.4 --- Realtime PCR --- p.81 / Chapter 2.4 --- Immunocytochemistry --- p.83 / Chapter 2.5 --- Western Blotting --- p.85 / Chapter 2.5.1 --- Protein extraction and quantification --- p.85 / Chapter 2.5.2 --- Western Blotting --- p.85 / Chapter 2.6 --- Enzyme-linked Immunosorbent Assay (ELISA) --- p.87 / Chapter 2.6.1 --- Detection of cell viability --- p.87 / Chapter 2.6.2 --- Detection of cell proliferation --- p.87 / Chapter 2.6.3 --- Measurement of Cell death --- p.88 / Chapter 2.6.4 --- Measurement of IGF 1 level in condition medium --- p.89 / Chapter 2.6.5 --- Measurement of glucose induced insulin secretion --- p.90 / Chapter 2.7 --- Regeneration model --- p.92 / Chapter 2.7.1 --- Regeneration model in neonatal-STZ rat --- p.92 / Chapter 2.7.2 --- Change in IGF1 expression in pancreas and liver --- p.92 / Chapter 2.8 --- Statistical Data Analysis --- p.93 / Chapter Chapter 3 --- Vitamin D and vitamin A receptor expression and the proliferative effects of ligand activation of these receptors on the development of pancreatic progenitor cells derived from human fetal pancreas. (Stem Cell Rev. 2011;7:53-63) / Chapter 3.1 --- Abstract --- p.95 / Chapter 3.2 --- Introduction --- p.97 / Chapter 3.3 --- Materials and Methods --- p.101 / Chapter 3.3.1 --- Fetal Tissue Procurement --- p.101 / Chapter 3.3.2 --- Culture of Pancreatic Progenitor Cells --- p.101 / Chapter 3.3.3 --- RNA Expression Analysis by Reverse Transcription-Polymerase Chain Reaction (RT-PCR) --- p.102 / Chapter 3.3.4 --- Western Blot Analysis --- p.103 / Chapter 3.3.5 --- Immunocytochemstry --- p.105 / Chapter 3.3.6 --- PPC Proliferation Assays --- p.106 / Chapter 3.3.7 --- PPC Cell Death Assays --- p.107 / Chapter 3.3.8 --- Statistical Data Analysis --- p.108 / Chapter 3.4 --- Results --- p.110 / Chapter 3.4.1 --- "Expression and Localization of RAR, VDR and RXR, CYP26 and CYP24 in PPCs" --- p.110 / Chapter 3.4.2 --- Incubation of PPC with atRA Enhances PPC Viability due to Increased Proliferation and Anti-apoptosis --- p.111 / Chapter 3.4.3 --- Incubation of PPCs with Calcitriol Enhances Viability due to Increased Proliferation --- p.111 / Chapter 3.4.4 --- Both atRA and Calcitriol Induce Up-regulation of both the RAR and the VDR but not the RXR --- p.112 / Chapter 3.4.5 --- Combination Treatment with atRA and Calcitriol on Cell Viability and NGN3 Expression --- p.112 / Chapter 3.5 --- Discussion --- p.114 / Chapter Chapter 4 --- Human fetal liver stromal cell co-culture enhances the growth and differentiation of pancreatic progenitor cells into islet-like cell clusters (In submission to Gastroenterology) / Chapter 4.1 --- Abstract --- p.128 / Chapter 4.2 --- Introduction --- p.129 / Chapter 4.3 --- Materials and Methods --- p.133 / Chapter 4.3.1 --- Use of human and animal tissues --- p.133 / Chapter 4.3.2 --- "Cell preparation, characterizations and Differentiation" --- p.133 / Chapter 4.3.3 --- Examination of PPC growth and ICC differentiation and functions with LSC co-culture --- p.133 / Chapter 4.3.3 --- Identification of growth factors and investigation of their effects --- p.134 / Chapter 4.3.4 --- Statistical Analysis --- p.135 / Chapter 4.4 --- Results --- p.136 / Chapter 4.4.1 --- "Isolation, Culture and Characterizations of LSCs" --- p.136 / Chapter 4.4.2 --- Establishment of LSC co-culture system --- p.136 / Chapter 4.4.3 --- LSC co-culture enhances PPC-derived ICC differentiation --- p.137 / Chapter 4.4.4 --- Differential expression of mRNA for cytokines and growth factors between 1st and 2nd trimester LSCs --- p.138 / Chapter 4.4.5 --- Characterization of IGF 1 receptors in PPCs and the effects of exogenous IGF1 on PPC growth and ICC differentiation --- p.139 / Chapter 4.4.6 --- Neutralizing antibodies against IGF1R inhibit ICC differentiation --- p.140 / Chapter 4.5 --- Discussion --- p.142 / Chapter 4.6 --- Supplementary Materials and Methods --- p.147 / Chapter 4.6.1 --- Cell Preparation and culture --- p.147 / Chapter 4.6.2 --- In Vitro ICC differentiation --- p.148 / Chapter 4.6.3 --- RNA expression analysis --- p.149 / Chapter 4.6.4 --- Immunocytochemistry --- p.149 / Chapter 4.6.5 --- PPC viability and cell count assays --- p.150 / Chapter 4.6.6 --- IGF1 and insulin ELISA --- p.151 / Chapter 4.6.7 --- Western blotting analysis --- p.152 / Chapter 4.6.8 --- Neonatal streptozotocin regeneration model --- p.153 / Chapter Chapter 5 --- General Discussion and Future Studies / Chapter 5.1 --- General Discussion --- p.165 / Chapter 5.1.1 --- Proliferative effects and enhance expression of NGN3 by vitamin A and vitamin D on PPC --- p.166 / Chapter 5.1.2 --- Induction of PPC derived ICCs by LSCs --- p.169 / Chapter 5.1.3 --- Potential effects of liver stroma derived IGF1 on PPC derived ICCs differentiation --- p.172 / Chapter 5.1.4 --- Significance of islet engineering in the management of diabetes --- p.174 / Chapter 5.1.5 --- Conclusions --- p.176 / Chapter 5.2 --- Future Studies --- p.177 / Chapter Chapter 6 --- Reference / Reference --- p.180

The study of diabetes mellitus is vital in this day and age because its incidence is increasing at an alarming rate. Diabetes results in the loss of function of beta-cells within the pancreas. Insulin resistance contributes to diabetes but the human body can compensate in various ways such as increasing the islet cell mass, glucose disposal and insulin secretion, in order to prevent the onset of diabetes. Growth hormone (GH) and insulin-like growth factor-I (IGF-I) are two integral hormones important in both glucose homeostasis and islet cell growth. Early studies using cultured islet cells have demonstrated positive regulation of beta-cell growth by both GH and IGF-I. To evaluate their relevance on normal beta-cell growth, compensatory growth, as well as in insulin responsiveness, we have used two mouse models that represent opposite manipulations of the GH/IGF-I axis. Specifically, the growth hormone receptor gene deficient (GHR-/-) and the IGF-I overexpression (MT-IGF) mice, to help understand the role of glucose homeostasis and islet cell growth in the GH/IGF-I axis. GH is essential for somatic growth and development as well as maintaining metabolic homeostasis. It is known that GH stimulates normal islet cell growth. Moreover, GH may also participate in islet cell overgrowth and compensate for insulin resistance induced by obesity. To determine whether the islet cell overgrowth is dependent on GH signaling, we studied the response of GHR-/- mice to high-fat diet (HFD)-induced obesity. We also studied the insulin responsiveness in GHR-/- mice. On the other hand, IGF-I promotes embryonic development, postnatal growth and the maturation of various organ systems. The notion that IGF-I stimulates islet cell growth has been challenged in recent years by results from IGF-I and receptor gene targeted models. We have characterized MT-IGF mice which overexpress the IGF-I gene. / The results of our studies indicate that (1) GH is essential for normal islet cell growth, but not required for compensatory overgrowth of the islets in response to obesity, (2) GHR gene deficiency caused delayed insulin responsiveness in skeletal muscle; in contrast to elevated insulin sensitivity in the liver; (3) although overexpression does not stimulate islet cell growth, a chronic IGF-I elevation caused significant hypoglycemia, hypoinsulinemia, and improved glucose tolerance, (4) finally IGF-I overexpression mice are resistant to experimental diabetes.

Diss. (sammanfattning) Linköping : Linköpings universitet, 2006. / Härtill 4 uppsatser.

Thesis (Ph.D. in Molecular Biology) -- University of Colorado Denver, 2007. / Typescript. Includes bibliographical references (leaves 162-196). Free to UCD affiliates. Online version available via ProQuest Digital Dissertations;

Thesis (Ph.D. in Molecular Biology) -- University of Colorado at Denver and Health Sciences Center, 2006. / Typescript. Includes bibliographical references (leaves 137-151). Free to UCD Anschutz Medical Campus. Online version available via ProQuest Digital Dissertations;

Diss. (sammanfattning) Linköping : Linköpings universitet, 2008. / Härtill 4 uppsatser.

Thesis (M.Sc.). / Written for the Dept. of Surgery, Division of Surgical Research. Title from title page of PDF (viewed 2009/06/30). Includes bibliographical references.

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