The overall objective of this research was to understand the mechanims by which growth hormone (GH) regulates insulin-like growth factor-I (IGF-I) gene expression in liver. Previous studies have suggested that GH regulation of IGF-I gene expression in liver is mediated by binding of the transcription factor signal transducer and activator of transcription (STAT) 5 to four binding sites located distantly from the IGF-I promoter. The first specific objective of this research was to determine whether additional STAT5 binding sites were involved in GH stimulation of IGF-I gene expression in liver. Sequence analysis of 170 kb of mouse genomic DNA revealed nineteen consensus STAT5 binding sequences corresponding to fourteen ~200 bp chromosomal regions that were conserved in the corresponding human DNA sequence. Eight of these chromosomal regions were able to mediate STAT5 activation of reporter gene expression in cotransfection experiments. Two of these chromosomal regions corresponded to those previously identified. Gel-shift assays indicated that the eight new STAT5 binding sites and three of the four previously identified STAT5 binding sites could bind GH-activated STAT5 from mouse liver. Together, these results suggest that GH stimulation of IGF-I gene transcription in the mouse liver may be mediated by at least eleven STAT5 binding sites located distantly from the IGF-I promoter. In a previous study, I found that liver expression of liver-enriched transcription factor hepatocyte nuclear factor 3γ (HNF-3γ) was increased by GH in cattle. Therefore, the second specific objective of this research was to determine how GH stimulates HNF-3γ gene expression and whether the increased HNF-3γ mediates GH stimulation of IGF-I gene expression in bovine liver. Sequence analysis of the bovine HNF-3γ promoter revealed the presence of two putative binding sites for STAT5. The proximal putative STAT5 binding site appears to be conserved in other mammals. Chromatin immunoprecipitation (ChIP) assays demonstrated that GH increased the binding of STAT5 to the HNF-3γ promoter in bovine liver and that this binding was associated with increased HNF-3γ expression. Gel-shift assays demonstrated that the proximal STAT5 binding site in the HNF-3γ promoter could bind GH-activated STAT5 from bovine liver. Cotransfection analyses showed that the proximal STAT5 binding site was necessary for the HNF-3γ promoter to be activated by GH. The promoter of the bovine IGF-I gene contains three putative HNF-3 binding sites that seem to be evolutionarily conserved. ChIP assays indicated that GH stimulated the binding of HNF-3γ to the IGF-I promoter in bovine liver. Gel-shift assays showed that one of the putative HNF-3 binding sites could bind HNF-3γ protein from bovine liver. Co-transfection analyses demonstrated that this HNF-3 binding site was necessary for HNF-3γ activation of reporter gene expression from the IGF-I promoter. In summary, the results of this dissertation research suggest that GH-activated STAT5 directly stimulates IGF-I gene transcription in liver by binding to at least eleven distantly located STAT5 binding sites in the IGF-I locus and indirectly stimulates IGF-I gene transcription by enhancing HNF-3γ gene expression in the liver. / Ph. D.

Breast cancer is a leading cause of cancer death of women in the U.S. today. Members of the family of insulin-like growth factors (IGFs) are proposed to play a major role in the development and subsequent uncontrolled proliferation of breast cancer cells. Insulin-like growth factor-I (IGF-I) is known to be a potent mitogen for mammary epithelial cells. IGF-I acts by binding to cell surface receptors, thereby stimulating a cascade of events leading to cell division. In the interest of interrupting the effect of IGF-I on cancerous mammary epithelial cells, an understanding of how IGF-I behaves in the presence of other extracellular components is needed. This study examines the IGF-I response of SV40-IGF-I, an immortalized bovine mammary epithelial cell line which secretes IGF-I constitutively. The microphysiometer allows real-time sampling of cellular activity by measuring the excretion of protons from a sample of cells stimulated by IGF-I binding. The contributions of other factors in enhancing or suppressing stimulation can be compared by examining the pH response of cells exposed to IGF-I in the presence of these factors. We present data showing the stimulatory effect of IGF-I in a dose dependent manner on the SV40-IGF-I cell line. In addition, we compare IGF-I stimulation with stimulation by long R3IGF-I, a substituted analogue of IGF-I having a reduced binding affinity for the IGF binding proteins. We examine the effect of insulin-like binding protein-3 (IGFBP-3) both in the presence and absence of IGF-I, finding no IGF-I independent effect in the rapid binding experiment and no effect on stimulation of IGFBP-3 pre-incubated cells by subsequent IGF-I challenge. This is of particular interest due to recent work demonstrating an IGF-independent IGFBP-3 response in a number of cell lines. Binding studies to correlate with the rapid binding stimulation show binding of the IGFBP-3 molecule with high affinity to a small number of surface receptors on the SV40-IGF-I cell. Analysis of the extracellular environment and the components contributing to the binding of IGF-I to the cell membrane receptor will provide information for the development of interventions to slow or interrupt the process of IGF-I binding and therefore cancer growth. Optimization of the Cytosensor(r) Microphysiometer System for the (transfected) SV40-IGF-I and the (parental) MAC-T cell lines was achieved to continue comparison studies of autocrine and paracrine stimulation of bovine mammary epithelial cells by IGF-I. This work was supported by the Whitaker Foundation Biomedical Engineering Grant. / Master of Science

Na infecção por Leishmania a resposta imune se inicia logo após a inoculação de promastigotas no indivíduo. Nesse contexto vai haver a participação de diversos fatores da resposta imune inata que vai direcionar para uma resposta imune adaptativa responsável pela evolução da doença. Um desses fatores que participa dessa interação parasito-hospedeiro é o fator de crescimento insulina-símile I (IGF-I). Foi demonstrado que o IGF-I extrínseco favorece a proliferação do parasito e progressão da infecção. No entanto, IGF-I está presente constitutivamente em macrófagos. Neste trabalho avaliamos a expressão do IGF-I, o parasitismo e a produção de óxido nítrico em macrófagos murinos infectado por Leishmania (L.) amazonensis e o efeito da inibição de IGF-I no parasitismo após o silenciamento do IGF-I por RNA de interferência. Macrófagos peritoneiais foram infectados por 2 e 4 horas com promastigotas de L. (L.) amazonensis na presença de soro fetal bovino (SFB) 5% e Albumina de Soro Bovino 0,5% (BSA) na presença ou ausência de small-interfering RNA (siRNA) de IGF-I e lipossoma (Lipo). As células foram lavadas e mantidas depois em meio de cultura por 24, 48 e 72 h. Quando o recombinante para IGF-I foi adicionado separadamente durante a incubação inicial o parasitismo aumentou em relação ao controle. Quando o siRNA foi adicionado houve diminuição na expressão de IGF-I e consequentemente diminuição no parasitismo em relação ao controle. Os resultados obtidos sugerem um papel importante de IGF-I na infecção de macrófagos peritoneais de camundongos murinos por Leishmania (l.) amazonensis. / In Leishmania infection the immune response begins soon after the inoculation of promastigotes in the individual. In this context will be the participation of several factors of the innate immune response that will direct to an adaptive immune response responsible for the evolution of the disease. One of these factors that participates in this parasite-host interaction is the insulin-like growth factor I (IGF-I). It has been shown that extrinsic IGF-I favors parasite proliferation and infection progression. However, IGF-I is constitutively present in macrophages. In this work we evaluated the expression of IGF-I, parasitism and nitric oxide production in murine macrophages infected with Leishmania (L.) amazonensis and the effect of IGF-I inhibition on parasitism after IGF-I silencing by RNA from interference. Peritoneal macrophages were infected for 2 and 4 hours with L. (L.) amazonensis promastigotes in the presence of 5% fetal bovine serum (FBS) and 0.5% Bovine Serum Albumin (BSA) in the presence or absence of IGF-I small-interfering RNA (siRNA) and liposome (Lipo). Cells were washed and then maintained in culture medium for 24, 48 and 72 h. When the recombinant IGF-I was added separately during the initial incubation the parasitism increased relative to the control. When the siRNA was added there was a decrease in IGF-I expression and consequently a decrease in parasitism in relation to the control. The results obtained suggest an important role of IGF-I in the infection of murine mouse peritoneal macrophages by Leishmania (L.) amazonensis.

Nas leishmanioses, sabe-se que tanto na resistência quanto na suscetibilidade à infecção, a resposta imune celular é considerada a mais importante. No entanto, na fase inicial, fatores inespecíficos estão sendo considerados fundamentais na determinação do curso da doença, como o fator de crescimento insulina-símile I (\"insulin-like growth factor\"-IGF-I). Em trabalhos anteriores realizados no grupo de pesquisa da Profa. Dra. Hiro Goto mostraram que IGF-I extrínseco favorece a proliferação do parasito e progressão da infecção, com diminuição na produção de óxido nítrico e ativação da arginase de macrófagos e do parasito. Sabendo que os macrófagos produzem intrinsecamente IGF-I, avaliamos o efeito do fator intrínseco no parasitismo em macrófagos de camundongos BALB/c infectados por L. (L.) infantum silenciando a expressão do RNA mensageiro (mRNA) de IGF-I na célula pela técnica de RNA de interferência (siRNA). Iniciamos avaliando a expressão do mRNA de IGF-I e do seu receptor (IGF-IR). Foi observado uma diminuição de 1,4 vezes da expressão do mRNA de IGF-I em 24 horas e um aumento de 1,5 vezes em 48 horas quando comparado com o grupo controle. Também foi observado um aumento na expressão de mRNA do receptor de IGF-I em 24 como em 48 horas nos grupos infectados quando comparado com o grupo controle. Com o silenciamento do IGF-I por siRNA, houve diminuição da expressão de mRNA do IGF-I no macrófago em torno de 71% em 24 horas e de 51% em 48 hora. Na ausência ou diminuição do IGF-I no macrófago, observou-se uma diminuição do parasitismo na infecção com promastigotas, sendo o parasitismo recuperado com a reposição de IGF-I extrínseco no sistema, atestando a importância de IGF-I na proliferação do parasito. Esses resultados reforçam a importância do IGF-I na infecção por L. infantum, sugerindo que o IGF-I está diretamente relacionado ao parasitismo. / In leishmaniasis, it is known that in both resistance and susceptibility to infection, the cellular immune response is considered the most important. However, in the initial phase, nonspecific factors are being considered as fundamental in determining the course of the disease, such as insulin-like growth factor I (IGF-I). Studies carried out in the research group of Profa. Dr. Hiro Goto showed that extrinsic IGF-I favors parasite proliferation and infection progression, with decrease in nitric oxide production and activation of arginase of macrophages and parasite. It is known that macrophages produced IGF-I (intrinsic IGF-I), thus, in the present study we have investigated the effect of the intrinsic factor in the parasitism on macrophages of BALB/c mice infected with L. (L.) infantum by silencing the expression of messenger RNA (IGF-I mRNA) in the cell by the interference RNA technique (siRNA). We started evaluating the expression of IGF-I mRNA and its receptor (IGF-IR). A 1.4-fold decrease in IGF-I mRNA expression was observed in 24 hours and a 1.5-fold increase in 48 hours as compared to the control group. An increase in mRNA expression of the IGF-IR was also observed in 24 as well as in 48 hours in the infected groups as compared to the control group. With IGF-I silencing by siRNA, there was a decrease in IGF-I mRNA expression in the macrophage around 71% in 24 hours and 51% in 48 hours. In the absence or decrease of IGF-I in the macrophage, a decrease in the parasitism in the infection with promastigotes was observed, and the parasitism recovered with the replacement of extrinsic IGF-I in the system, confirming the importance of IGF-I in the proliferation of the parasite. These results reinforce the importance of IGF-I in L. infantum infection, suggesting that IGF-I is directly related to the parasitism.

Cheung Chun Kai. / Thesis submitted in: December 2003. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 133-146). / Abstracts in English and Chinese. / Acknowledgements --- p.ii / Abstract --- p.iv / 摘要 --- p.vii / Table of Contents --- p.ix / List of Tables --- p.xv / List of Figures --- p.xvi / List of Abbreviations --- p.xxi / Chapter Chapter 1 --- Overview --- p.1 / Chapter Chapter 2 --- Literature Review --- p.3 / Chapter 2.1 --- Historical background --- p.3 / Chapter 2.2 --- Insulin-like growth factor --- p.5 / Chapter 2.2.1 --- Structure and synthesis --- p.5 / Chapter 2.2.2 --- Physiologic role and biological actions --- p.6 / Chapter 2.3 --- Insulin-like growth factor binding protein-3 --- p.8 / Chapter 2.3.1 --- Structure and synthesis --- p.8 / Chapter 2.3.2 --- Physiologic role and biological actions --- p.8 / Chapter 2.4 --- Clinical aspects --- p.10 / Chapter 2.4.1 --- Metabolic effects of IGF-1 --- p.10 / Chapter 2.4.1.1 --- Similarities between IGF-I and insulin --- p.11 / Chapter 2.4.1.2 --- Differences between IGF-I and insulin --- p.13 / Chapter 2.4.2 --- Glucose and protein metabolism --- p.14 / Chapter 2.4.3 --- Therapeutic use of IGF-I --- p.15 / Chapter 2.4.3.1 --- Type 1 diabetes mellitus --- p.16 / Chapter 2.4.3.2 --- Type 2 diabetes mellitus --- p.17 / Chapter 2.4.4 --- Side effects --- p.19 / Chapter 2.5 --- World demands --- p.21 / Chapter 2.5.1 --- Significance of large-scale production --- p.21 / Chapter 2.5.2 --- IGF-I production --- p.21 / Chapter 2.6 --- Plants as bioreactors --- p.24 / Chapter 2.6.1 --- Medical molecular farming --- p.24 / Chapter 2.6.2 --- Advantages of plant bioreactor --- p.24 / Chapter 2.6.3 --- Commercial biopharmaceutical protein --- p.25 / Chapter 2.7 --- Tobacco expression system --- p.26 / Chapter 2.7.1 --- Tobacco model plant --- p.26 / Chapter 2.7.2 --- Transformation methods --- p.26 / Chapter 2.8 --- Hypotheses and aims of study --- p.28 / Chapter Chapter 3 --- Expression of Human IGF-I and IGFBP-3 in Transgenic Tobacco --- p.30 / Chapter 3.1 --- Introduction --- p.30 / Chapter 3.2 --- Materials and methods --- p.31 / Chapter 3.2.1 --- Chemicals --- p.31 / Chapter 3.2.2 --- Plant materials --- p.31 / Chapter 3.2.3 --- Bacterial strains --- p.32 / Chapter 3.2.4 --- Codon modification of IGF-I and IGFBP-3 cDNAs --- p.32 / Chapter 3.2.5 --- Transient assay to study IGF-I or IGFBP-3 translatability --- p.39 / Chapter 3.2.5.1 --- Construction of chimeric genes for particle bombardment --- p.39 / Chapter 3.2.5.2 --- Particle bombardment of GUS fusion constructs --- p.42 / Chapter 3.2.6 --- Construction of chimeric genes for tobacco transformation --- p.44 / Chapter 3.2.6.1 --- Construction of chimeric genes with different promoters --- p.44 / Chapter 3.2.6.1.1 --- Construction of chimeric gene with CaMV 35S promoter --- p.44 / Chapter 3.2.6.1.2 --- Construction of chimeric genes with phaseolin promoter --- p.46 / Chapter 3.2.6.2 --- Construction of fusion constructs --- p.48 / Chapter 3.2.6.2.1 --- Construction of GUS fusion constructs --- p.48 / Chapter 3.2.6.2.2 --- Construction of LRP fusion constructs --- p.51 / Chapter 3.2.6.3 --- Construction of phaseolin targeting constructs --- p.56 / Chapter 3.2.6.3.1 --- Construction of phaseolin targeting constructs without AFVY --- p.56 / Chapter 3.2.6.3.2 --- Construction of phaseolin targeting constructs with AFVY --- p.60 / Chapter 3.2.6.4 --- Cloning of chimeric genes into Agrobacterium binary vector pBI 121 --- p.64 / Chapter 3.2.7 --- Confirmation of sequencing fidelity of chimeric genes --- p.66 / Chapter 3.2.8 --- Transformation of Agrobacterium by electroporation --- p.66 / Chapter 3.2.9 --- Transformation of tobacco --- p.67 / Chapter 3.2.10 --- Selection and regeneration of transgenic tobacco --- p.67 / Chapter 3.2.11 --- GUS assay --- p.68 / Chapter 3.2.12 --- Extraction of leaf genomic DNA --- p.68 / Chapter 3.2.13 --- PCR of genomic DNA --- p.69 / Chapter 3.2.14 --- Synthesis of DIG-labeled double-stranded DNA probe --- p.69 / Chapter 3.2.15 --- Southern blot analysis --- p.70 / Chapter 3.2.16 --- Extraction of total RNA from leaves or developing seeds --- p.70 / Chapter 3.2.17 --- Northern blot analysis --- p.71 / Chapter 3.2.18 --- Extraction of total protein --- p.71 / Chapter 3.2.19 --- Tricine SDS-PAGE --- p.72 / Chapter 3.2.20 --- Western blot analysis --- p.72 / Chapter 3.2.21 --- Enterokinase digestion of fusion protein --- p.73 / Chapter Chapter 4 --- Results --- p.74 / Chapter 4.1 --- Particle bombardment for transient assay --- p.74 / Chapter 4.1.1 --- Construction of GUS fusion genes for particle bombardment --- p.74 / Chapter 4.1.2 --- Transient expression of GUS fusion genes in soybean cotyledons and tobacco leaves --- p.76 / Chapter 4.2 --- Construction of chimeric genes for tobacco transformation --- p.78 / Chapter 4.3 --- "Tobacco transformation, selection and regeneration" --- p.81 / Chapter 4.4 --- Detection of GUS activity --- p.83 / Chapter 4.5 --- Detection of transgene integration --- p.84 / Chapter 4.5.1 --- Extraction of genomic DNA and PCR --- p.84 / Chapter 4.5.2 --- Southern blot analysis --- p.88 / Chapter 4.6 --- Detection of transgene transcription --- p.92 / Chapter 4.6.1 --- Extraction of total RNA --- p.92 / Chapter 4.6.2 --- Northern blot analysis --- p.92 / Chapter 4.7 --- Detection of transgene translation --- p.99 / Chapter 4.7.1 --- Extraction of total protein and Tricine SDS-PAGE --- p.99 / Chapter 4.7.2 --- Western blot analysis --- p.102 / Chapter 4.7.3 --- Enterokinase digestion of fusion protein --- p.109 / Chapter Chapter 5 --- Discussion --- p.111 / Chapter 5.1 --- Codon modification of IGF-I and IGFBP-3 cDNAs --- p.114 / Chapter 5.2 --- Transient expression of IGF-I and IGFBP-3 cDNAs --- p.116 / Chapter 5.3 --- Fusion of IGF-I and IGFBP-3 cDNA with LRP gene --- p.118 / Chapter 5.4 --- Enterokinase digestion --- p.120 / Chapter 5.5 --- Phaseolin targeting signal --- p.122 / Chapter 5.6 --- Gene silencing --- p.124 / Chapter 5.7 --- Future perspectives --- p.128 / Chapter Chapter 6 --- Conclusion --- p.131 / References --- p.133

Insulin-like growth factor I (IGF-I) is a polypeptide protein hormone similar to insulin. It plays an important role in growth and anabolic effects in life. Most circulating IGF-I is bound to high-affinity insulin-like growth factor binding protein-3 (IGFBP-3), to form a complex (IGF-I/IGFBP-3) that can treat growth hormone insensitivity syndrome (GHIS) and can lower plasma glucose in diabetic patients. Its side effects can be reduced without affecting the therapeutic efficacy. Human insulin-like growth factor binding protein 3 (hIGFBP-3) alone is an anti-tumor agent. It has been shown to have anti-proliferation effect on numerous cancer cells, such as breast, prostate and liver cancers. / Our previous study has demonstrated that recombinant hIGF-I (rhIGF-I) and hIGFBP-3 (rhIGFBP-3) could be synthesized in transgenic tobacco plant. In the present study, we propose to establish an efficient bioreactor platform for mass production of hIGF-I and hIGFBP-3 in rice, as rice grain contains 8-15% of protein by dry weight. In order to enhance rhIGF-I and rhIGFBP-3 stability and yield, and to control their glycosylation, various constructs were designed and transformed into rice by Agrobacterium-mediated transformation. Protein targeting signal sequence (KDEL) was fused to direct the target proteins to specific compartments in rice grain for glycosylation in the Golgi apparatus or for stable accumulation without complex glycan processing in the endoplasmic reticulum. These expression constructs were driven by seed-specific glutelin promoter (Gt1pro). Western blot analysis showed that the rhIGF-I and rhIGFBP-3 were successfully expressed in transgenic rice grains. Biological activity of rhIGF-I was evidenced by the induction of membrane ruffling in L6 rat skeletal muscle cells, while rhIGFBP-3 was effective in inhibiting the effect of IGF-I on membrane ruffling of L6 cell. Moreover, rhIGFBP-3 was also found to inhibit the growth of human breast cancer MCF-7 cells. Biological activity results showed that the active expression levels of rhIGF-I and rhIGFBP-3 were found to be 10 ug and 7.36 ug per 1 g of rice seed respectively. These findings suggested that both rice-produced rhIGF-I and rhIGFBP-3 were biologically active. / Cheung, Chun Kai. / "September 2007." / Adviser: Peter Tong Chun Yip. / Source: Dissertation Abstracts International, Volume: 69-08, Section: B, page: 4555. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (p. 209-243). / 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. / Abstract in English and Chinese. / School code: 1307.

O nível sérico do Fator de crescimento semelhante à insulina tipo I (IGF-I) é fundamental para auxiliar no dignóstico e controle terapêutico dos transtornos relacionados à secreção do Hormônio de Crescimento (GH), bem como no diagnóstico e seguimento de outras doenças. Estabelecer valores de referência para as dosagens séricas de IGF-I por um ensaio imunoquimioluminométrico (ICMA), utilizando o sistema automatizado Immulite 2000/Diagnostic Products Corporation (DPC), e por um ensaio imunoradiométrico (IRMA), utilizando o kit comercial ACTIVE IGF-I/Diagnostic System Laboratories (DSL)-5600, numa população brasileira adulta da cidade do Rio de Janeiro. Este estudo, aprovado pelo Comitê de Ética do Instituto Estadual de Hematologia Arthur de Siqueira Cavalcanti, Rio de Janeiro, Brasil, incluiu amostras de 484 indivíduos saudáveis (251 homens e 233 mulheres) com idades entre 18 e 70 anos. As amostras foram estudadas por ICMA- Immulite 2000/DPC and IRMA- ACTIVE IGF-I/DSL-5600. Para análise dos dados foram utilizados modelos específicos para idade e sexo, após transformação dos dados de IGF-I. Foi observada uma lenta diminuição dos níveis de IGF-I com a idade usando ambos os ensaios. Os níveis de IGF-I foram signicativamente (p=0,0181) mais elevados em mulheres do que em homens, quando as amostras foram analisadas usando ICMA. Não houve diferença significativa dos níveis de IGF-I entre homens e mulheres quando as amostras foram analisadas usando IRMA. Este estudo estabeleceu valores de referência de IGF-I específicos para idade e sexo, determinados com o sistema automatizado ICMA-Immulite 2000/DPC, e valores de referência de IGF-I específicos para idade, determinados com o kit comercial IRMA- ACTIVE IGF-I/DSL-5600, em uma população adulta brasileira, da cidade do Rio de Janeiro. / Serum level of insulin-like growth factor I (IGF-I) is fundamental in order to aid in the diagnosis and follow-up of growth hormone (GH)-related disorders, as well as in the diagnosis and follow-up of other diseases. The aim of this investigation was to determine reference values for IGF-I using an automated immunochemiluminometric assay (ICMA) system Immulite 2000/Diagnostic Products Corporation (DPC); and an immunoradiometric assay (IRMA), using the commercial kit ACTIVE IGF-I/Diagnostic System Laboratories (DSL)-5600, in an adult Brazilian population of Rio de Janeiro city. The study, approved by the Ethical Committee of the Instituto Estadual de Hematologia Arthur de Siqueira Cavalcanti, Rio de Janeiro, Brazil, included samples of blood taken from 484 healthy subjects (251men, 233 women) aged from 18 up to 70. The samples were analyzed by ICMA- Immulite 2000/DPC and IRMA- ACTIVE IGF-I/DSL-5600. For statistical analysis, age and sex-specific models were fitted after transformation of IGF-I values. In adulthood, a slow age-dependent decrease was found, using both assays. IGF-I in women were significantly (p=0,0181) higher than in men when samples were analayzed using ICMA.There was no significant difference between men and women IGF-I values when samples were analayzed using IRMA. The present study established age- and sex specific IGF-I reference values, determined with the automated system: ICMA-Immulite 2000/DPC and age-specific IGF-I reference values determined with the IRMA- ACTIVE IGF-I/DSL-5600, in an adult Brazilian population of Rio de Janeiro city.

Objective: Insulin-like growth factor-I (IGF-I) has been suggested to be a prognostic marker for the development of cancer and, more recently, cardiovascular disease. These diseases are closely linked to obesity, but reports of the association of IGF-I with measures of obesity are divergent. In this study, we assessed the association of age-dependent IGF-I standard deviation scores with body mass index (BMI) and intra-abdominal fat accumulation in a large population. Design: A cross-sectional, epidemiological study. Methods: IGF-I levels were measured with an automated chemiluminescence assay system in 6282 patients from the DETECT study. Weight, height, and waist and hip circumference were measured according to the written instructions. Standard deviation scores (SDS), correcting IGF-I levels for age, were calculated and were used for further analyses. Results: An inverse U-shaped association of IGF-I SDS with BMI, waist circumference, and the ratio of waist circumference to height was found. BMI was positively associated with IGF-I SDS in normal weight subjects, and negatively associated in obese subjects. The highest mean IGF-I SDS were seen at a BMI of 22.5–25 kg/m2 in men (+0.08), and at a BMI of 27.5–30 kg/m2 in women (+0.21). Multiple linear regression models, controlling for different diseases, medications and risk conditions, revealed a significant negative association of BMI with IGF-I SDS. BMI contributed most to the additional explained variance to the other health conditions. Conclusions: IGF-I standard deviation scores are decreased in obesity and underweight subjects. These interactions should be taken into account when analyzing the association of IGF-I with diseases and risk conditions.

Objective: IGF1 is associated with metabolic parameters and involved in glucose metabolism. Low-IGF1 has been implicated in the etiology of glucose intolerance and subjects with pathological causes of either low- or high-IGF1 are at risk of diabetes. We hypothesized that both low- and high-IGF1 levels increase the risk of diabetes and aimed to assess the role of IGF1 in the risk of developing diabetes in a large prospective study. Design: An analysis of two prospective cohort studies, the DETECT study and SHIP. Methods: We measured IGF1 levels in 7777 nondiabetic subjects and assessed incident diabetes mellitus during follow-up. Results: There were 464 cases of incident diabetes during 32 229 person-years (time of follow-up in the DETECT study and SHIP: 4.5 and 5 years respectively). There was no heterogeneity between both studies (P>0.4). The hazard ratios (HRs) of incident diabetes in subjects with IGF1 levels below the 10th or above the 90th age- and sex-specific percentile, compared to subjects with intermediate IGF1 levels, were 1.44 (95% confidence interval (CI) 1.07–1.94) and 1.55 (95% CI 1.06–2.06) respectively, after multiple adjustment. After further adjustment for metabolic parameters, the HR for low-IGF1 became insignificant. Analysis of IGF1 quintiles revealed a U-shaped association of IGF1 with risk of diabetes. Results remained similar after exclusion of patients with onset of new diabetes within 1 year or with borderline glucose or HbA1c levels at baseline. Conclusions: Subjects with low- or high-IGF1 level are at increased risk of developing diabetes.

Thesis (Ph. D.)--University of Washington, 2003. / Includes bibliographical references (leaves 101-113).