No description available.

The objective of this thesis was to investigate the effects of the somatotrope GH/IGF-1 axis upon the thymus. This work included two parts: 1. Translational research study: Thymus function in adult GH deficiency (AGHD) with and without GH treatment Background: Despite age-related adipose involution, T cell generation in the thymus (thymopoiesis) is maintained beyond puberty in adults. In rodents, growth hormone (GH), insulin-like growth factor-1 (IGF-1), and GH secretagogues reverse agerelated changes in thymus cytoarchitecture and increase thymopoiesis. GH administration also enhances thymic mass and function in HIV-infected patients. Until now, thymic function has not been investigated in adult GH deficiency (AGHD). The objective of this clinical study was to evaluate thymic function in AGHD, as well as the repercussion upon thymopoiesis of GH treatment for restoration of GH/IGF-1 physiological levels. Methodology/Principal Findings: Twenty-two patients with documented AGHD were enrolled in this study. The following parameters were measured: plasma IGF-1 concentrations, signal-joint T-cell receptor excision circle (sjTREC) frequency, and sj/b TREC ratio. Analyses were performed at three time points: firstly on GH treatment at maintenance dose, secondly one month after GH withdrawal, and thirdly one month after GH resumption. After 1-month interruption of GH treatment, both plasma IGF-1 concentrations and sjTREC frequency were decreased (p,0.001). Decreases in IGF-1 and sjTREC levels were correlated (r = 0.61, p,0.01). There was also a decrease in intrathymic T cell proliferation as indicated by the reduced sj/b TREC ratio (p,0.01). One month after reintroduction of GH treatment, IGF-1 concentration and sjTREC frequency regained a level equivalent to the one before GH withdrawal. The sj/b TREC ratio also increased with GH resumption, but did not return to the level measured before GH withdrawal. Conclusions: In patients with AGHD under GH treatment, GH withdrawal decreases thymic T cell output, as well as intrathymic T cell proliferation. These parameters of thymus function are completely or partially restored one month after GH resumption. These data indicate that the functional integrity of the somatotrope GH/IGF-1 axis is important for the maintenance of a normal thymus function in human adults. 2. Fundamental study: intrathymic expression of members of the GH/IGF-1 axis and effects of GH on T-cell differentiation in murine fetalthymic organ cultures (FTOC). We here address the question of expression and role of GH/IGF axis in the thymus. Methods: Using RT-qPCR, the expression profile of various components of the somatotrope GH/IGF axis was measured in different thymic cell types and during thymus embryogenesis in Balb/c mice. Effect of GH on T-cell differentiation was explored through thymic organotypic culture. Results: Transcription of Gh, Igf1, Igf2 and their related receptors predominantly occurred in thymic epithelial cells (TEC), while a low level of Gh and Igf1r transcription was also evidenced in thymic T cells (thymocytes). Gh, Ghr, Ins2, Igf1, Igf2, and Igfr1, displayed distinct expression profiles depending on the developmental stage. The protein concentration of IGF-1 and IGF-2 were in accordance with the profile of their gene expression. In fetal thymus organ cultures (FTOC) derived from Balb/c mice, treatment with exogenous GH resulted in a significant increase of double negative CD4-CD8- T cells and CD4+ T cells, with a concomitant decrease in double positive CD4+CD8+ T cells. These changes were inhibited by concomitant treatment with GH and GHR antagonist pegvisomant. However, GH treatment also induced a significant decrease in FTOC Gh, Ghr and Igf1 expression. Conclusion: These data show that the thymotropic properties of the somatotrope GH/IGF-1 axis involve an interaction between exogenous GH and GHR expressed by TEC. Since thymic IGF-1 is not increased by GH treatment, the effects of GH upon T-cell differentiation could implicate a different local growth factor or cytokine.

No description available.

(EN) GH/IGF-1 axis components (GH, growth hormone receptor (GH-R), IGF-1, IGF-1 receptor (IGF-1R), IGF-binding proteins (IGFBPs)) participate in the control of glucose metabolism, inflammatory processes as well as cell proliferation and differentiation, including adipocytes and monocytes. The aim of the present study was to evaluate the role of local mRNA expression of GH/IGF-1 axis components in subcutaneous adipose tissue (SCAT) and peripheral monocytes (PM) in the development of insulin resistance and differences of adipose tissue mass in following groups of patients: obese females with and without type 2 diabetes mellitus and subjects with active untreated acromegaly. A total number of 66 subjects were included in the study: obese females without type 2 diabetes mellitus (OB), obese females with type 2 diabetes mellitus (T2DM), acromegalic patients (AC) and healthy lean control subjects (C). T2DM underwent 2 weeks of very-low- calorie diet (VLCD - energy content 2500 kJ/day). According to our results we suggest that decreased mRNA expression of IGF-1, IGF-1R, IGFBP-2 and IGFBP-3 in adipose tissue of T2DM subjects may contribute to changes of fat differentiation capacity and the increased IGF-1R mRNA expression in peripheral monocytes in these patients may play a role in the regulation of...

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Idiopathic Short Stature is a heterogeneous set of conditions without obvious hormonal changes or defined etiologies. It may include the partial insensitivity to GH (PGHI) and the moderate GH deficiency (MGHD), both of them with low concentrations of growth factor like insulin type I (IGF-I) and hyper or sub-answer of GH on tests of stimulation, respectively. The objective of this study is to assess the response to treatment with GH in PGHI and MGHD, comparing them twith the results obtained in a group with severe GH deficiency (SGHD). It was studied in PGHI (GH peak ≥18 ng/ml) 20 individuals (14 boys), 12.07 (2.57-year-old); in MGHD (GH peak between 5 and 10 ng/ml) 12 (7 boys), 10.73 (1.79-year-old); and in SGHD (GH peak lower than 5 ng/ml) 19 (10 boys), 10.90-(3.51) yearold, treated with GH for one to ten years. The initial and present GH doses were, respectively, 43.33(10.00) and 49.61 (12.90) μg/kg/day in SGHD, 50.27 (11.76) and 57.27 (15.83) μg/kg/day in MGHD; and50.18 (6.99) and 55.66 (9.61) μg/kg/day in PGHI. The standard deviation score (SDS) of initial height of the SGHD group was lower than MGHD group (p< 0.01) and PGHI group (p <0.001).The SDS of initial IGF-I of SGHD was similar to MGHD and lower than PGHI group (p<0.0001).The initial bone age (BA) in SGHD group was similar to MGHD and lower than PGHI group GH (p < 0.01). GH treatment has brought about a lower increase in the height SSD and in the IGF-I SSD (both, p < 0.05) and in the bone age (p< 0.01) in the PGHI group than in the SGHD group, probably due to the more accentuated height deficit in the SGHD group and lower IGF-I increase in the PGHI group. Treatment response was similar in MGHD and SGHD groups. The lowest height gain in the PGHI suggests that the partial GH insensitivity needs higher GH doses to be effective. / A baixa estatura idiopática é um conjunto heterogêneo de condições sem evidentes alterações hormonais ou etiologias definidas. Pode incluir a insensibilidade parcial ao GH (IPGH) e a deficiência moderada de GH (DMGH), ambas com concentrações baixas de fator de crescimento semelhante à insulina tipo I (IGF-I) e hiper ou sub-resposta do GH aos testes de estímulo, respectivamente. O objetivo do presente trabalho é avaliar a resposta ao tratamento com GH na IPGH e DMGH, comparando-as com os resultados obtidos na deficiência grave de GH (DGGH). Foram estudados no grupo IPGH (pico de GH ≥18 ng/ml), 20 indivíduos (14 meninos), com 12,0 (2,57) anos de idade; no grupo DMGH (pico de GH entre 5 e 10 ng/ml), 12 (sete meninos), com 10,73 (1,79) anos; e no DGGH (pico de GH < 5 ng/ml), 19 (10 meninos), com 10,90 (3,51) anos, tratados com GH por um a dez anos. As doses de GH iniciais e atuais foram, respectivamente, 43,33 (10,00) e 49,61 (12,90) μg/kg/dia no DGGH; 50,27 (11,76) e 57,27 (15,83) μg/kg/dia no DMGH; e 50,18 (6,99) e 55,66 (9,61) μg/kg/dia no IPGH. O escore de desvio-padrão (EDP) da altura inicial do grupo DGGH foi menor do que no DMGH (p< 0,01) e no IPGH (p <0, 001). O EDP do IGF-I inicial do grupo DGGH foi similar ao DMGH e menor do que o do IPGH (p< 0, 0001). A idade óssea inicial no grupo DGGH foi similar ao DMGH e menor do que a do grupo IPGH (p < 0,01). O tratamento com GH propiciou um menor incremento no EDP da altura e no EDP do IGF-I (ambos, p < 0,05) e na IO (p< 0,01) no grupo IPGH do que no DGGH, provavelmente refletindo o maior déficit estatural no grupo com DGGH e menor aumento do IGF-I no grupo IPGH. A resposta ao tratamento nos grupos DMGH e DGGH foi semelhante. O ganho estatural menor no grupo IPGH sugere que a insensibilidade parcial ao GH necessitaria de doses mais altas de GH para ser vencida.

The GH/IGF-I axis is important for bone growth, but its effects on joint function are not completely understood. Adult onset GH deficient (GHD) individuals have often reduced bone mineral density (BMD). However, there are limited data on BMD in adult patients with untreated congenital isolated GHD (IGHD). We have shown that adult IGHD individuals from the Itabaianinha, homozygous for the c.57+1G>A GHRHR mutation, have reduced bone stiffness, but BMD and joint status in this cohort are unknown. The objective is to study BMD, joint function, and osteoarthritis score in IGHD adults harboring c.57+1G > A GHRHR mutation, previously untreated. It was performed a cross-sectional study. Areal BMD by dual-energy X-ray absorptiometry was measured in 25 IGHD and 23 controls. Volumetric BMD (vBMD) was calculated at the lumbar spine and total hip. Joint function was assessed by goniometry of elbow, hips and knees. X rays were used to measure the anatomic axis of knee and the severity of osteoarthritis, using a classification for osteophytes (OP) and joint space narrowing (JSN). Genu valgum was more prevalent in IGHD than controls. The osteoarthritis knees OP score was similar in both groups, and knees JSN score showed a trend to be higher in IGHD. The hips OP score, and JSN score were higher in IGHD. Areal BMD was lower in IGHD than controls, but vBMD was similar in the two groups. Range of motion was similar in elbow, knee and hip in IGHD and controls. Untreated congenital IGHD due inactivating GHRHR mutation causes hip joint osteoarthritis problems and genu valgum, without apparent clinical significance, reduces bone size but does not reduce vBMD of the lumbar spine and hip. / O eixo GH/IGF-I é importante para o crescimento e desenvolvimento ósseo, mas seus efeitos na densidade mineral óssea (DMO) e na função articular não são completamente conhecidos. Indivíduos com deficiência de GH (DGH) no início da vida adulta tem frequentemente redução da DMO. Entretanto, existem dados limitados em indivíduos com deficiência isolada e congênita do hormônio do crescimento (DIGH). Mostramos que indivíduos adultos com DIGH, decorrente de uma mutação no GHRHR tipo c.57+1G>A, provenientes da coorte de Itabaianinha, não tratados, apresentam uma redução da rigidez óssea, mas a DMO e a função articular dessa coorte são desconhecidas. O objetivo desse trabalho é estudar a DMO, a severidade da osteoartrite, a função e a anatomia articular em uma população de indivíduos com DIGH de ambos os sexos, portando a mutação c.57+1G > A GHRHR, provenientes de Itabaianinha. Foi realizado um estudo transversal, através da realização da densitometria óssea com cálculo da DMO areal e volumétrica (DMOv) em coluna lombar, quadril total e corpo inteiro, em 25 indivíduos com DIGH e 23 controles. A função articular foi avaliada pela goniometria dos cotovelos, quadris e joelhos. Radiografias foram feitas para mensurar o eixo anatômico do joelho e a severidade da osteoartrite, baseada numa adaptação da classificação da Sociedade Internacional de pesquisa da OA a partir dos osteófitos (OF) e estreitamento do espaço articular (EEA). Os resultados mostraram que DMO areal foi menor que nos controles, mas a DMOv foi similar em ambos os grupos. A amplitude de movimentos dos cotovelos, quadris e joelhos foram semelhantes em ambos os grupos. Geno valgo foi mais prevalente nos indivíduos com DIGH que nos controles. No joelho, o escore de osteoartrite para OF foi similar em ambos os grupos e o escore para EEA mostrou uma tendência a ser mais elevado na DIGH. No quadril, os escores de OF e do EEA foram maiores no DIGH. Em conclusão, DIGH congênita não tratada causa osteoartrite no quadril e geno valgo, sem aparente importância clínica, reduz o tamanho do osso, mas não reduz a DMOv da coluna lombar e quadril.

(EN) GH/IGF-1 axis components (GH, growth hormone receptor (GH-R), IGF-1, IGF-1 receptor (IGF-1R), IGF-binding proteins (IGFBPs)) participate in the control of glucose metabolism, inflammatory processes as well as cell proliferation and differentiation, including adipocytes and monocytes. The aim of the present study was to evaluate the role of local mRNA expression of GH/IGF-1 axis components in subcutaneous adipose tissue (SCAT) and peripheral monocytes (PM) in the development of insulin resistance and differences of adipose tissue mass in following groups of patients: obese females with and without type 2 diabetes mellitus and subjects with active untreated acromegaly. A total number of 66 subjects were included in the study: obese females without type 2 diabetes mellitus (OB), obese females with type 2 diabetes mellitus (T2DM), acromegalic patients (AC) and healthy lean control subjects (C). T2DM underwent 2 weeks of very-low- calorie diet (VLCD - energy content 2500 kJ/day). According to our results we suggest that decreased mRNA expression of IGF-1, IGF-1R, IGFBP-2 and IGFBP-3 in adipose tissue of T2DM subjects may contribute to changes of fat differentiation capacity and the increased IGF-1R mRNA expression in peripheral monocytes in these patients may play a role in the regulation of...

Tillväxthormon och insulinliknande tillväxtfaktor-1 är blodprover som tas vid misstanke om akromegali. Immulite 2000 XPi är ett instrument som använder chemiluminescent microparticle immunoassay metodik för att kvantitativt mäta koncentrationen av GH och IGF-1. Analys av biokemiska markörer påverkas av flera olika faktorer. En viktig sådan faktor är hemolys. Hemolys innebär att de röda blodkropparna går sönder, vilket leder till frisättning av dess innehåll såsom hemoglobin i serum/plasma. Syftet med detta projekt var att undersöka hur hemolys påverkar resultatet av GH- och IGF-1-prover på immulite 2000 XPi. Utifrån erhållna resultat kommer klinisk kemi vid Universitetssjukhuset Örebros laboratorie rutiner vid hemolytiska prover på GH eller IGF-1 att uppdateras . Hemolys tillverkades och tillsattes till olika serumprover med låg och hög nivå av GH respektive IGF-1 för att erhålla prover med varierande grad av hemolys. Resultatet visade att ökande hemolysindex korrelerar med GH- respektive IGF-1-koncentrationer, med undantag för den låga GH koncentrationen som inte uppvisade någon korrelation till hemolysindex. En 10%:ig skillnad av GH och IGF-1- koncentrationer uppnåddes vid en ökning av hemolysindex med 555,40 mg/dL för GH respektive 333,3 mg/dL för IGF-1.Utifrån resultaten var hemolysgränsen likvärdig med tillverkarens gränser. Därför kan klinisk kemi på Universitetssjukhuset Örebro fortsätta med nuvarande hemolysgränser. / Growth hormone and insulin-like growth factor-1 are blood samples taken upon suspicion of acromegaly and for follow-up of acromegaly treatment. Immulite 2000 XPi is an instrument that uses chemiluminescent microparticle immunoassay method to quantitatively measure the concentration of GH and IGF-1. Analysis of biochemical markers is affected by several different factors. An important such factor is hemolysis. Hemolysis means that the red blood cells break, whose contents leak into the serum/plasma. The study aimed to investigate how hemolysis affects the results of GH and IGF-1 samples on the Immulite 2000 XPi. The results will determine the routines for hemolytic samples for GH or IGF-1 at Örebro University Hospital. Hemolysis was produced and added to various serum samples with low and high levels of GH and IGF-1 to obtain samples with varying degrees of hemolysis. The results showed that increasing hemolysis index correlates with GH and IGF-1 concentrations, with the exception of low GH concentration, which did not show any correlation to hemolysis index. A 10% difference in GH and IGF-1 concentrations was achieved with an increase in hemolysis index of 555.40 mg/dL for GH and 333.3 mg/dL for IGF-1. Based on the results, the hemolysis limit was equivalent to the manufacturer's limits. Therefore, clinical chemistry at Örebro University Hospital can continue with current hemolysis limits.

La pulsatililité des sécrétions hormonales est cruciale dans le système endocrine, puisqu'elle confère aux hormones : leur rôle et leur efficacité d'action. Dans ce cadre, l'objectif de ma thèse a été d'étudier l'implication de l'horloge circadienne, qui contrôle les rythmes journaliers de nombreux aspects de la physiologie et du comportement, dans ces pulsatilités endocrines. Dans un premier temps, nous avons étudié deux fonctions impliquant une activité neuroendocrine pulsatile - la croissance et la reproduction -, chez les souris Cry1-/-Cry2-/-, dépourvues d'horloge circadienne fonctionnelle. Les principaux résultats indiquent, premièrement, que l'horloge circadienne interfère avec la pulsatilité ultradienne de GH, et deuxièmement, que l'horloge circadienne est nécessaire au maintien des cycles infradiens liés à la reproduction. Cette étude montre, d'une part, que l'horloge circadienne joue un rôle dans les mécanismes responsables des pulsatilités hormonales, et d'autre part, qu'elle peut contrôler des rythmes non-circadiens. Dans un second temps, afin de comprendre à quel niveau l'horloge agit pour réguler les pulsatilités endocrines, nous nous sommes intéressés à l'hypophyse, une glande majeure du système endocrine, qui présente différents types de pulsatilités, circadiennes et non circadiennes. L'hypophyse exprime les principaux gènes et protéines horloges avec un rythme journalier. Et, bien que les différentes cellules endocrines qui la composent, aient un fonctionnement rythmique différent, leurs horloges sont en phase. Enfin, l'horloge hypophysaire semble intégrer différents signaux : la lumière et la nourriture. Cette caractérisation sert de base pour de nouvelles études visant à comprendre si l'horloge hypophysaire pourrait aussi coordonner l'activité des cellules endocrines au sein de la glande et ainsi favoriser l'émergence d'une pulsatilité globale.

Cost and benefits of high individual growth rates are likely to vary across different environments leading to geographic differentiation in growth strategies. In ectotherms, habitats constrained by short growing seasons favour rapid growth and development leading to adaptive latitudinal clines in these traits. Geographic variation in growth strategies should be influenced by physiological variation as well as environmental factors, however many of these mechanisms remain largely unexplored. In my thesis, I studied hormonal correlates of growth strategies, and compensatory responses to phenological variation and environmental stress in anuran tadpoles. I tested the hypotheses that fast growing high latitude common frog Rana temporaria tadpoles have higher growth hormone (GH) expression, and low stress hormone (CORT) elevation in response to predator stress. I found no relationship between GH expression and latitude, but CORT response decreased with latitude after 24 hours of predator exposure. Lower CORT response at high latitude can be adaptive as it may enable the tadpoles to maintain high growth in time constrained habitats. I also found that breeding phenology affected latitudinal variation in growth, development and anti-predator strategies. Northern R. temporaria tadpoles were phenotypically more similar to southern tadpoles when breeding occurred early, suggesting that part of the latitudinal variation is plastic and affected by yearly variation in phenology. When time stress was manipulated by delaying hatching, tadpoles were able to compensate by increasing their development and growth during the larval stage, decreasing the cost of the delayed development. In the final study, I found that northern tadpoles showed stronger compensatory growth during the larval stage than southern tadpoles after being delayed by low food, however, temperature manipulation did not induce differences in the compensatory responses. In general, my results highlight the roles of both environmental and genetic variation in determining individual growth strategies. / Felaktigt tryckt som Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 735