Is biochemical hypoglycemia necessary during an insulin tolerance test?

ABSTRACT Objective The insulin tolerance test (ITT) has been accepted as the gold standard test for assessing the integrity of the growth hormone (GH) - insulin-like growth factor (IGF-1) axis and the hypothalamic-pituitary-adrenal (HPA) axis. The goal of the test is to achieve clinical and biochemical hypoglycemia at a blood glucose level ≤ 40 mg/dL to effectively and correctly assess the HPA and GH-IGF-1 axes. In this study, the GH and cortisol responses of patients who achieved and failed to achieve biochemical hypoglycemia during an ITT were compared. Subjects and methods One hundred thirty-five patients with pituitary disorders were included in the study. Samples for blood glucose levels were obtained after clear symptoms of clinical hypoglycemia developed. The patients were enrolled in the hypoglycemic and nonhypoglycemic groups according to whether their plasma glucose level ≤ 40 mg/dL or > 40 mg/dL during an ITT, and the groups were compared in terms of their GH and cortisol responses. Results The mean age, body mass index and waist circumference of the two patient groups were found to be similar. The mean blood glucose level was significantly lower in the hypoglycemic group than in the nonhypoglycemic group (19.3 and 52.0 mg/dL, respectively). When the two groups were compared in terms of peak cortisol and GH responses, no statistically significant differences were found. Conclusion The data presented suggest that clinically symptomatic hypoglycemia is as effective as biochemically confirmed hypoglycemia during an ITT. Arch Endocrinol Metab. 2020;64(1):82-8

Laboratory investigations in the diagnosis and follow-up of GH-related disorders

ABSTRACT In addition to auxiological, clinical and metabolic features measurements of growth hormone (GH) and insulin-like growth factor I (IGF-I) complement our tools in diagnosis and follow-up of GH-related disorders. While comparably robust during the pre-analytical phase, measurement and interpretation of concentrations of both hormones can be challenging due to analytical issues and biological confounders. Assay methods differ in terms of antibody specificity, interference from binding proteins, reference preparations and sensitivity. GH assays have different specificity towards different GH-isoforms (e.g. 20 kDa GH, placental GH) and interference from the GH antagonist Pegvisomant. The efficacy to prevent binding protein interference is most important in IGF-I assays. Methodological differences between assays require that reference intervals and diagnostic cut-offs are assay-specific. Among biological variables, pubertal development and age are most relevant for IGF-I, making detailed reference intervals mandatory for interpretation. GH has pulsatile secretion and short half-life. Its concentration is modified by acute factors such as stress, exercise and sleep, but also by intake of oral estrogens and anthropometric factors (e.g. BMI). Other GH dependent biomarkers such as free IGF-I, IGF binding protein 3 (IGFBP 3) and acid labile subunit (ALS) have been proposed. Their concentrations largely mirror the information obtained through measurement of IGF-I, but their measurement can be helpful in particular situations. In this review, we describe the evolution of analytical methods to measure biomarkers of GH action, the impact of the methodological changes on laboratory results and the need to include biological variables in their interpretation. Arch Endocrinol Metab. 2019;63(6):618-29

Hormona de crecimiento en sangre de papel filtro para el diagnóstico de deficiencia de hormona de crecimiento / Growth hormone of dried blood spot for the diagnosis of growth hormone deficiency

INTRODUCCIÓN: El diagnóstico de deficiencia de hormona de crecimiento (DHC) es difícil de establecer, y se puede asociar a serias complicaciones, especialmente en el período neonatal. La prueba de estímulo de secreción de hormona de crecimiento (HC) se considera de elección para el diagnóstico, pero presenta complicaciones metodológicas y se asocia a efectos adversos. Los neonatos presentan aumento de la secreción de HC de forma fisiológica, siendo una ventana diagnóstica. OBJETIVO: Evaluar si la muestra de sangre en papel filtro tomada en el período neonatal, en contexto del tamizaje neonatal de hipotiroidismo congénito y fenilcetonuria, permite diferenciar pacientes con DHC, de los que no la presentan. PACIENTES Y MÉTODO: Estudio de casos y controles mediante determinación de concentración de HC en sangre de papel filtro extraída en período neonatal, comparando controles con DHC con casos con deficiencia descartada. Se realizó extracción de la muestra del papel filtro, obteniendo dos discos de 0,125 pulgada por cada uno de los pacientes desde el centro de la mancha de sangre del papel, para un ELISA de HC humana altamente sensible basado en el uso de anticuerpos policlonales dirigidos contra la HC humana recombinante de 22kDa de peso molecular. RESULTADOS: Se obtuvo un total de 7 casos de DHC y 10 controles. La mediana de concentración de HC de papel filtro en los casos es 2,0 ng/ml (Rango intercuartil 3,6 ng/ml) y controles 2,05 ng/mL (RIC 2,0 ng/ml), U de Mann-Withney 30,5 (p = 0,68). Los dos casos con deficiencia de hormonas hipofisarias múltiples (DHHM) presentan concentraciones menores a 1 ng/ml. CONCLUSIÓN: La muestra de papel filtro no permitió diferenciar a los pacientes con DHC de los casos controles, aunque los casos con DHHM presentaron concentraciones mucho menores, en comparación a la deficiencia de hormona de crecimiento aislada (DHCA).

INTRODUCTION: The diagnosis of growth hormone deficiency (GHD) is difficult to determine, and could be associated with severe complications, especially in the neonatal period. The stimulation test of growth hormone (GH) secretion is considered the gold standard for diagnosis, but it has methodological complications and is associated with adverse effects. Neonates present physiological increased secretion of GH, representing a diagnostic window. OBJECTIVE: To evaluate if the dried blood spot on filter paper obtained in the neonatal period, as part of a neonatal screening for con genital hypothyroidism and phenylketonuria, allows differentiating patients with GHD from those who do not have it. PATIENTS AND METHOD: Study of cases and controls by measuring the GH concen tration in dried blood spot on filter paper obtained in the neonatal period, comparing controls with GHD with cases with discarded deficiency. The sample was extracted from the filter paper, obtaining two 0.125 inch discs per each patient from the center of the blood spot on the paper, for a highly sen sitive ELISA assay for human GH based on the use of polyclonal antibodies against 22 kDa recom binant human GH. RESULTS: Seven cases of GHD and ten controls were obtained. The median GH concentration of the dried blood spot in the cases is 2.0 ng/ml (Interquartile range 3.6 ng/ml) and 2.05 ng/ml (Interquartile range 2.0 ng/ml) in the controls, Mann-Whitney U test 30.5 (p = 0.68). The two cases with multiple pituitary-hormone deficiency (MPHD) present concentrations lower than 1 ng/ml. CONCLUSION: The dried blood spot sample did not differentiate GHD patients from control cases, although MPHD cases present much lower concentrations compared to isolated growth hor mone deficiency (IGHD).

Correlation analysis between short-term insulin-like growth factor-I and glucose intolerance status after transsphenoidal adenomectomy in acromegalic patients: a large retrospective study from a single center in China

ABSTRACT Objectives: Our study aimed to investigate the associations of glucose tolerance status with insulin-like growth factor-I (IGF-I) and other clinical laboratory parameters of acromegalic patients before and after the patients underwent transsphenoidal adenomectomy (TSA) by conducting a single-center, retrospective study. Subjects and methods: A total of 218 patients with acromegaly who had undergone TSA as the first treatment were retrospectively analyzed. Serum IGF-I, growth hormone (GH) and glucose levels were measured before and after surgery. Results: The follow-up levels for random GH, GH nadir, and the percentage of the upper limit of normal IGF-I (%ULN IGF-I) were decreased significantly. The percentages of normal (39.0%), early carbohydrate metabolism disorders (33.0%) and diabetes mellitus (28.0%) changed to 70.2%, 16.5% and 13.3%, respectively, after TSA. %ULN IGF-I at baseline was higher in the diabetes mellitus (DM) group than in the normal glucose tolerance group and impaired glucose tolerance (IGT) /impaired fasting glucose (IFG) groups before TSA, and the DM group exhibited a greater reduction in %ULN IGF-I value after surgery. The follow-up %ULN IGF-I value after surgery was significantly lower in the improved group, and Pearson's correlation analysis revealed that the reductions in %ULN IGF-I corresponded with the reductions in glucose level. Conclusion: This study examined the largest reported sample with complete preoperative and follow-up data. The results suggest that the age- and sex-adjusted IGF-I level, which reflects altered glucose metabolism, and the change of it are associated with improved glucose tolerance in acromegalic patients both before and after TSA.

Long-term follow-up of patients with elevated IGF-1 and nadir GH > 0 4 µg/L but < 1 µg/L

ABSTRACT Objective To report the results of initial investigation and after 5 years of patients with a suspicious clinical scenario for acromegaly, elevated IGF-1, and nadir GH during an oral glucose tolerance test (OGTT) > 0.4 µg/L but < 1 µg/L. Subjects and methods Seventeen patients who had elevated IGF-1 (outside puberty and pregnancy) in two measurements and GH between 0.4 and 1 µg/L during OGTT were selected. Results During initial assessment, only one patient had microadenoma on magnetic resonance imaging (MRI) of the pituitary. In this patient, IGF-1 returned to normal spontaneously after 5 years. In the remaining 16 patients, spontaneous normalization of IGF-1 was observed in four and IGF-1 continued to be elevated in 12 after 5 years. None of the latter patients developed a phenotype of acromegaly, changes in physiognomy or increase in IGF-1 and no tumor was detected by imaging methods. Two patients had nadir GH < 0.4 µg/L, while the nadir GH remained between 0.4 and 1 µg/L in 10 patients. Conclusion In patients (notably young adult or adult women) without a typical phenotype in whom IGF-1 is measured due to a suspicious clinical scenario and is found to be slightly elevated, even if confirmed and in the absence of other causes, a nadir GH cut-off value of 0.4 µg/L instead of 1 µg/L in the OGTT might be inadequate for the diagnosis.

Clonidine-stimulated growth hormone concentrations (cut-off values) measured by immunochemiluminescent assay (ICMA) in children and adolescents with short stature

OBJECTIVES: To establish cut-off values for growth hormone concentrations using clonidine as a secretagogue and an immunochemiluminescent assay as the method of measurement and to analyze the response time as well as the influence of gender, nutritional status and pubertal stage. METHODS: A total of 225 tests were performed in 3 patient groups, categorized as group 1 (normal), group 2 (idiopathic short stature) and group 3 (growth hormone deficiency). Among the 199 disease-free individuals, 138 were prepubertal, and 61 were pubertal. Clonidine (0.1 mg/m2) was orally administered, and the growth hormone level was measured by immunochemiluminescent assay. The growth hormone peak and the difference between the growth hormone peak and the baseline level were then analyzed. Statistical analyses were performed using Student’s t-test or the Mann-Whitney test and Kruskal-Wallis test followed by Dunn’s post hoc test. Cut-off values were determined using a receiver operating characteristic curve. RESULTS: Group 1 and group 2 had no difference in growth hormone peak, gender, body mass index standard deviation score, or pubertal stage. Group 3 exhibited a significantly lower growth hormone peak than the other groups did. The receiver operating characteristic curve demonstrated that growth hormone concentrations ≥ 3.0 ng/mL defined responsiveness to clonidine. In total, 3.02% of individuals in group 1 and group 2 were considered false positive, i.e., these children lacked growth hormone deficiency and had a peak below 3.0 ng/mL. CONCLUSION: Clonidine-stimulated growth hormone concentrations ≥3 ng/mL, as measured by immunochemiluminescent assay, suggest responsiveness to the stimulus regardless of gender, body mass index standard deviation score or pubertal stage.

Clinical, hormonal and radiological features of partial Sheehan's syndrome: an Indian experience

ABSTRACT Objective The objective of this study was to describe clinical presentation, hormonal profile and imaging characteristics of 21 patients with partial Sheehan’s syndrome. Subjects and methods This prospective study was carried out over a period of six years (2008-2013). The evaluation of patients included clinical assessment, hormone estimations and contrast enhanced magnetic resonance imaging of pituitary. Results We documented preservation of gonadotroph, corticotroph and lactotroph function in 71.4, 61.9, and 9.5% of patients respectively. Conclusion To conclude some of the pituitary functions can be preserved in Sheehan’s syndrome and this has important implications from the treatment and long term morbidity point of view.

Prevalence of lung structure abnormalities in patients with acromegaly and their relationship with gas exchange: cross-sectional analytical study with a control group / Prevalência de alterações na estrutura pulmonar em pacientes com acromegalia e sua relação com a troca gasosa: estudo transversal analítico com grupo controle

CONTEXT AND OBJECTIVE: Different functional respiratory alterations have been described in acromegaly, but their relationship with pulmonary tissue abnormalities is unknown. The objective of this study was to observe possible changes in lung structure and explain their relationship with gas exchange abnormalities. DESIGN AND SETTING: Cross-sectional analytical study with a control group, conducted at a university hospital. METHODS: The study included 36 patients with acromegaly and 24 controls who were all assessed through high-resolution computed tomography of the thorax (CT). Arterial blood gas, effort oximetry and serum growth hormone (GH) and insulin-like growth factor I (IGF-1) were also assessed in the patients with acromegaly. RESULTS: The abnormalities found in the CT scan were not statistically different between the acromegaly and control groups: mild cylindrical bronchiectasis (P = 0.59), linear opacity (P = 0.29), nodular opacity (P = 0.28), increased attenuation (frosted glass; P = 0.48) and decreased attenuation (emphysema; P = 0.32). Radiographic abnormalities were not associated with serum GH and IGF-1. Hypoxemia was present in seven patients; however, in six of them, the hypoxemia could be explained by underlying clinical conditions other than acromegaly: chronic obstructive pulmonary disease in two, obesity in two, bronchial infection in one and asthma in one. CONCLUSION: No changes in lung structure were detected through thorax tomography in comparison with the control subjects. The functional respiratory alterations found were largely explained by alternative diagnoses or had subclinical manifestations, without any plausible relationship with lung structural factors.

CONTEXTO E OBJETIVO: Diferentes alterações funcionais respiratórias são descritas na acromegalia. Sua relação com anormalidades do tecido pulmonar é desconhecida. O objetivo foi observar possíveis alterações da estrutura pulmonar e explicar sua relação com anormalidades da troca gasosa. TIPO DE ESTUDO E LOCAL: Estudo transversal, analítico, com grupo de controle, realizado em um hospital universitário. MÉTODOS: Incluíram-se 36 pacientes com acromegalia e 24 controles que foram avaliados com tomografia computadorizada de alta resolução de tórax (TC); os acromegálicos também foram avaliados com gasometria arterial, oximetria de esforço e dosagens de hormônio de crescimento (GH) e fator de crescimento semelhante à insulina (IGF-1). RESULTADOS: As alterações encontradas na TC não foram estatisticamente diferentes entre os grupos acromegálico e de controle: bronquiectasia cilíndrica leve (P = 0,59), opacidades lineares (P = 0,29), opacidades nodulares (P = 0,28), aumento da atenuação (vidro fosco) (P = 0,48) e redução da atenuação (enfisema; P = 0,32). As alterações radiológicas não se relacionaram com as dosagens de GH e IGF-1. Hipoxemia estava presente em sete pacientes; contudo, em seis deles a hipoxemia poderia ser explicada por condição clínica subjacente diversa da acromegalia: doença pulmonar obstrutiva crônica em dois, obesidade em dois, infecção brônquica em um e asma em um. CONCLUSÕES: Não foram observadas alterações da estrutura pulmonar por tomografia de tórax, quando comparadas ao grupo de controle; as alterações funcionais respiratórias encontradas são explicáveis em grande parte por diagnósticos alternativos, ou se manifestam de forma subclínica, não apresentando relação plausível com o aspecto da estrutura pulmonar.

Laboratory investigation of acromegaly: Is basal or random GH > 0.4 µg/L in the presence of normal serum IGF-1 an important result?

Objective To determine the frequency of indication of the GH suppression test and pituitary magnetic resonance imaging (MRI) in patients with clinical suspicion of acromegaly with GH concentrations > 0.4 µg/L despite normal serum IGF-1. Subjects and methods A total of 160 patients with clinical suspicion of acromegaly with normal IGF-1 were studied. Results Basal GH > 0.4 µg/L was observed in 70/88 women (79.5%). Nadir GH > 0.4 µg/L was found in 21/70 women (30%) and these patients were submitted to MRI, which revealed a microadenoma in 2/21 women (9.5%). In these two women, IGF-1 continued to be normal in subsequent measurements and no clinical progression has been observed so far (time of follow-up until now 4 years). Basal GH > 0.4 µg/L was seen in 33/72 men (45.8%). Nadir GH was < 0.4 µg/L in all of them. Conclusions In patients with clinical suspicion of acromegaly, concern over GH concentration in the presence of normal IGF-1 results in the unwarranted complementary investigation in many cases, and even in possible equivocal diagnoses. It is only in exceptional cases that normal IGF-1 should not rule out acromegaly. Arch Endocrinol Metab. 2015;59(1):54-8 .

Pituitary macroadenoma presenting as a nasal tumor: case report / Macroadenoma hipofisário, apresentando-se como um tumor nasal: relato de caso

CONTEXT: Pituitary macroadenomas are rare intracranial tumors. In a few cases, they may present aggressive behavior and invade the sphenoid sinus and nasal cavity, causing unusual symptoms. In this paper, we report an atypical case of pituitary adenoma presenting as a nasal mass. CASE REPORT: The patient was a 44-year-old woman who had had amenorrhea and galactorrhea for ten months, with associated nasal obstruction, macroglossia and acromegaly. Both growth hormone and prolactin levels were increased. Magnetic resonance imaging showed a large mass originating from the lower surface of the pituitary gland, associated with sella turcica erosion and tumor extension through the sphenoid sinus and nasal cavity. Histopathological analysis demonstrated a chromophobe pituitary adenoma with densely packed rounded epithelial cells, with some atypias and rare mitotic figures. There was no evidence of metastases. CONCLUSION: Macroadenoma invading the nasal cavity is a rare condition and few similar cases have been reported in the literature. This study contributes towards showing that tumor extension to the sphenoid sinus and nasopharynx needs to be considered and investigated in order to make an early diagnosis when atypical symptoms like nasal obstruction are present. .

CONTEXTO: Macroadenomas hipofisários são tumores intracraniais raros. Em alguns casos, podem apresentar comportamento agressivo e invadir o seio esfenoidal e a cavidade nasal, causando sintomas não usuais. Neste relato de caso, descrevemos um caso atípico de adenoma hipofisário manifestando-se como uma massa nasal. RELATO DE CASO: A paciente de 44 anos, do sexo feminino, apresentava amenorreia e galactorreia por 10 meses associando-se a obstrução nasal, macroglossia e acromegalia. Os níveis do hormônio de crescimento e de prolactina apresentaram-se aumentados. Ressonância magnética mostrou uma grande massa originada da superfície inferior da glândula hipofisária associada com erosão da sela túrcica e extensão do tumor através do seio esfenoidal e cavidade nasal. Análise histopatológica demonstrou adenoma hipofisário cromófobo com células epiteliais arrendondadas densamente agrupadas com algumas atipias e escassas figuras de mitose. Não houve evidências de metástase. CONCLUSÃO: O macroadenoma invasivo para a cavidade nasal é uma condição rara e há poucos relatos similares descritos na literatura. Este trabalho contribui para mostrar que, na presença de sintomas atípicos como a obstrução nasal, a extensão para o seio esfenoidal e para a nasofaringe deve ser considerada e investigada para um diagnóstico precoce. .

Comparison between the growth response to growth hormone (GH) therapy in children with partial GH insensitivity or mild GH deficiency / Comparação entre a resposta de crescimento ao tratamento com hormônio de crescimento (GH) em crianças com insensibilidade parcial ao GH ou deficiência de GH leve

Objectives: GH therapy is still controversial, except in severe GH deficiency (SGHD). The objective of this study was to compare the response to growth hormone (GH) therapy in children with partial GH insensitivity (PGHIS) and mild GH deficiency (MGHD) with those with SGHD.Subjects and methods: Fifteen PGHIS, 11 MGHD, and 19 SGHD subjects, followed up for more than one year in the Brazilian public care service, were evaluated regarding anthropometric and laboratory data at the beginning of treatment, after one year (1 st year) on treatment, and at the last assessment (up to ten years in SGHD, up to four years in MGHD, and up to eight years in PGHIS).Results: Initial height standard deviation score (SDS) in SGHD was lower than in MGHD and PGHIS. Although the increase in 1 st year height SDS in comparison to initial height SDS was not different among the groups, height-SDS after the first year of treatment remained lower in SGHD than in MGHD. There was no difference in height-SDS at the last assessment of the children among the three groups. GH therapy, in the entire period of observation, caused a trend towards lower increase in height SDS in PGHIS than SGHD but similar increases were observed in MGHD and SGHD.Conclusion: GH therapy increases height in PGHIS and produces similar height effects in MGHD and SGHD.

Objetivos: O tratamento com GH é ainda controverso, salvo na deficiência grave de GH (SGHD). O objetivo deste estudo foi comparar a resposta ao tratamento com GH em indivíduos com insensibilidade parcial ao GH (PGHIS) e na deficiência moderada do GH (MGHD) com SGHD.Sujeitos e métodos: Quinze pacientes com PGHIS, 11 com MGHD e 19 com SGHD, seguidos por mais de um ano no Sistema Único de Saúde, foram avaliados antropométrica e laboratorialmente, no início, com um ano de tratamento e na última avaliação (tempo máximo de dez anos na SGHD, quatro anos na MGHD e oito anos na PGHIS).Resultados: O escore de desvio-padrão (EDP) da estatura inicial foi menor nos indivíduos com SGHD do que naqueles com MGHD e PGHIS. Embora o aumento no EDP da estatura no primeiro ano em comparação com o inicial não fosse diferente entre os grupos, o EDP da altura no primeiro ano de tratamento permaneceu menor na SGHD que na MGHD. Não houve diferença no EDP da estatura na última avaliação entre os três grupos. O tratamento com GH, no período completo da observação, provocou uma tendência a menor aumento no EDP da estatura nos pacientes com PGHIS que naqueles com SGHD, entretanto aumentos semelhantes foram encontrados nos grupos MGHD e SGHD.Conclusão: O tratamento com GH aumentou a estatura nos indivíduos com PGHIS e produziu efeitos similares na estatura em MGHD e SGHD.

Reappraisal of serum insulin-like growth factor-I (IGF-1) measurement in the detection of isolated and combined growth hormone deficiency (GHD) during the transition period / Reavaliação da dosagem sérica do fator de crescimento insulina-símile-1 (IGF-1) para o diagnóstico da deficiência isolada e combinada de hormônio de crescimento no período de transição

OBJECTIVE: To evaluate the accuracy of serum IGF-1 in the detection of isolated (IGHD) or combined growth hormone deficiency (CGHD) at the transition phase. SUBJECTS AND METHODS: Forty nine patients with GHD during childhood [16 with IGHD (10 men) and 33 with CGHD (24 men); age 23.2 ± 3.5 yrs.] were submitted to an insulin tolerance test (ITT) with a GH peak < 5 µg/L used for the diagnosis of GHD at the transition phase. Pituitary function and IGF-1 measurements were evaluated in the basal sample of the ITT. Transition patients were reclassified as GH-sufficient (SGH; n = 12), IGHD (n = 7), or CGHD (n = 30). RESULTS: Five (31%) patients with IGHD and 32 (97%) with CGHD at childhood persisted with GHD at retesting. One patient with IGHD was reclassified as CGHD, whereas 3 patients with CGHD were reclassified as IGHD. Mean GH peak was 0.2 ± 0.3 µg/L in the CGHD, 1.3 ± 1.5 µg/L in the IGHD, and 18.1 ± 13.1 µg/L in the SGH group. Serum IGF-1 level was significantly higher in the SGH (272 ± 107 ng/mL) compared to IGHD (100.2 ± 110) and CGHD (48.7 ± 32.8) (p < 0.01). All patients reclassified as CGHD, 86% reclassified as IGHD, and 8.3% reclassified as SGH had low IGF-1 level, resulting in 97.3% sensitivity and 91.6% specificity in the detection of GHD at the transition period; the cutoff value of 110 ng/mL showed 94.5% sensitivity and 100% specificity. Mean IGF-1 values did not differ in IGHD or CGHD associated with one, two, three, or four additional pituitary deficiencies. CONCLUSION: IGF-1 measurement is accurate to replace ITT as initial diagnostic test for IGHD and CGHD detection at the transition phase.

OBJETIVO: Avaliar a acurácia da dosagem sérica de IGF-1 no diagnóstico da deficiência de hormônio de crescimento isolada (DGHI) ou combinada (DGHC) na fase de transição. SUJEITOS E MÉTODOS: Quarenta e nove pacientes com DGH na infância [16 DGHI (10 homens) e 33 DGHC (24 homens); idade 23,2 ± 3,5 anos] realizaram teste de tolerância à insulina (TTI), com pico de GH < 5 µg/L considerado diagnóstico de DGH na transição. Função hipofisária e níveis de IGF-1 foram determinados na amostra basal do TTI e os pacientes foram reclassificados em GH suficientes (SGH; n = 12), DGHI (n = 7) ou DGHC (n = 30). RESULTADOS: Cinco (31%) pacientes com DGHI e 32 (97%) com DGHC na infância persistiram com DGH no reteste. Um paciente com DGHI foi reclassificado como DGHC e três com DGHC como DGHI. Os picos médios de GH foram 0,2 ± 0,3 µg/L (DGHC), 1,3 ± 1,5 µg/L (DGHI) e 18,1 ± 13,1 µg/L (SGH). O nível médio de IGF-1 foi maior no grupo SGH (272 ± 107 ng/mL) comparado com DGHI (100,2 ± 110) e DGHC (48,7 ± 32,8) (p < 0,01). IGF-1 baixo foi observado em todos os pacientes reclassificados como DGHC, 86% dos DGHI e 8,3% dos SGH, resultando em sensibilidade de 97,3% e especificidade de 91,6% para detecção de DGH na transição; valor de corte de 110 ng/mL mostrou 94,5% sensibilidade e 100% especificidade. O nível médio de IGF-1 foi similar nos pacientes com DGHI ou DGHC com uma, duas, três ou quatro deficiências hipofisárias associadas. CONCLUSÃO: A dosagem sérica de IGF-1 mostrou-se acurada para substituir o TTI na detecção tanto de DGHI como DGHC na transição.

Change in Somatostatinergic Tone of Acromegalic Patients according to the Size of Growth Hormone-Producing Pituitary Tumors

The aim of this study was to investigate the relationship between somatostatinergic tone (SST) and the size of growth hormone (GH)-producing pituitary tumors. GH levels of 29 patients with newly diagnosed acromegaly were measured using a 75-gram oral glucose tolerance test (OGTT), an insulin tolerance test (ITT), and an octreotide suppression test (OST). Differences between GH levels during the ITT and the OGTT (DeltaGH(IO)), and between the OGTT and the OST at the same time point (DeltaGH(OS)) were compared according to the size of the tumor and the response pattern to the OST. DeltaGH(IO) of macroadenomas (n=22) was non-significantly higher than those of microadenomas while DeltaGH(OS) of macroadenomas were significantly higher than those of microadenomas. According to further analyses of macroadenomas based on the response pattern to the OST, GH levels during the ITT were significantly higher in non-responders. DeltaGH(OS) showed near-significant differences between responders and non-responders. In conclusion, as the size of the pituitary tumor increases, the effect of glucose on SST appears to be attenuated. Macroadenomas that are non-responders to the OST possess a portion of GH secretion exceeding the range of regulation by SST.

Eixo hormônio de crescimento/fator de crescimento semelhante à insulina-1: um possível fator não nutricional para o retardo de crescimento em crianças com paralisia cerebral / Growth hormone/insulin-like growth factor-1 axis: a possible non-nutritional factor for growth retardation in children with cerebral palsy

OBJETIVO: Avaliar o eixo hormônio de crescimento (GH)/fator de crescimento semelhante à insulina 1 (IGF-1) como possível fator não nutricional para o retardo de crescimento em crianças com paralisia cerebral (PC). MÉTODOS: Um estudo caso-controle foi realizado em um hospital universitário terciário. Trinta crianças com PC [sete crianças com crescimento normal (PC-N) e 23 com retardo de crescimento (PC-R)], 30 crianças com desnutrição proteico-energética (DPE), e 30 crianças sadias (grupo REF) tiveram avaliados seus parâmetros de crescimento, IGF-1 sérico, GH basal, e pico de GH após estímulo com insulina. RESULTADOS: Os pacientes com DPE apresentaram níveis basais mais elevados de GH do que os grupos PC-N, PC-R e REF (p = 0,026, p < 0,001 e p = 0,001, respectivamente). Após estímulo com insulina, os grupos PC-N, PC-R e DPE apresentaram níveis menores de GH se comparados ao grupo REF (p = 0,04, p = 0,007, p = 0,036, respectivamente). O nível de IGF-1 foi menor no grupo PC-R se comparado aos grupos PC-N e REF (p = 0,037 e p < 0,001, respectivamente), e no grupo DPE se comparado aos grupos PC-N e REF (p < 0,001 e p < 0,001, respectivamente). CONCLUSÕES: Os pacientes com PC-R não demonstraram a mesma resposta basal elevada do GH apresentada pelos pacientes com DPE, e responderam de forma inadequada ao estímulo com insulina, mas apresentaram níveis de IGF-1 comparáveis aos dos pacientes com DPE. Por outro lado, os pacientes com PC-N tiveram comportamento semelhante ao dos controles com relação aos níveis basais de GH e IGF-1, mas não responderam adequadamente ao estímulo com insulina. O grupo DPE apresentou GH basal elevado e IGF-1 baixo. Esses achados sugerem que fatores não nutricionais contribuem para o retardo de crescimento em crianças com PC.

OBJECTIVE: To assess growth hormone (GH)/insulin like growth factor-1 (IGF-1) axis as a possible non-nutritional factor for growth retardation in children with cerebral palsy (CP). METHODS: A case-control study was conducted at a tertiary university hospital. Thirty children with CP (seven children with normal growth [CP-N] and 23 with retarded growth [CP-R]), 30 children with protein energy malnutrition (PEM), and 30 healthy children (REF group) underwent an assessment of growth parameters, serum IGF-1, basal GH, and peak GH after stimulation with insulin. RESULTS: PEM patients had higher basal GH levels than CP-N, CP-R and REF groups (p = 0.026, p < 0.001, and p < 0.001 respectively). After insulin stimulation, CP-N, CP-R, and PEM patients had lower GH levels compared to the REF group (p = 0.04, p = 0.007, and p = 0.036 respectively). IGF-1 levels were lower in CP-R group compared to CP-N and REF groups (p = 0.037 and p < 0.001 respectively), and in PEM group compared to CP-N and REF groups (p < 0.001 and p < 0.001 respectively). CONCLUSIONS: CP-R patients failed to demonstrate the same high basal GH response as PEM patients, and responded inadequately to the insulin stimulation test, but they had IGF-1 levels comparable to those of PEM patients. On the other hand, CP-N patients behaved as controls regarding their basal GH and IGF-1 levels, but failed to respond adequately to the insulin stimulation test. The PEM group presented high basal GH and low IGF-1 levels. These findings suggest that non-nutritional factors contribute to growth retardation in CP children.

Hypertension-related factors in patients with active and inactive acromegaly / Fatores implicados com a hipertensão em pacientes com acromegalia ativa e inativa

INTRODUCTION: There are several complications of the cardiovascular system caused by acromegaly, especially hypertension. OBJECTIVES: To evaluate hypertension characteristics in patients with cured/controlled acromegaly and with the active disease. PATIENTS AND METHODS: Cross-sectional study of the follow-up of forty-four patients with acromegaly submitted to clinical evaluation, laboratory tests and cardiac ultrasound. Patients with cured and controlled disease were evaluated as one group, and individuals with active disease as second one. RESULTS: Forty-seven percent of the patients had active acromegaly, and these patients were younger and had lower blood pressure levels than subjects with controlled/cured disease. Hypertension was detected in 50 percent of patients. Subjects with active disease showed a positive correlation between IGF-1 and systolic and diastolic blood pressure levels (r = 0.48, p = 0.03; and r = 0.42, p = 0.07, respectively), and a positive correlation between IGF-1 and urinary albumin excretion (UAE) rates. In patients with active disease, IGF-1 was a predictor of systolic blood pressure, although it was not independent of UAE rate. For individuals with cured/controlled disease, waist circumference and triglycerides were the predictors associated with systolic and diastolic blood pressure. CONCLUSIONS: Our findings suggest that blood pressure levels in patients with active acromegaly are very similar, and depend on excess GH. However, once the disease becomes controlled and IGF-1 levels decrease, their blood pressure levels will depend on the other cardiovascular risk factors.

INTRODUÇÃO: Existem várias complicações no sistema cardiovascular causadas pela acromegalia, especialmente a hipertensão. OBJETIVOS: Avaliar as características da hipertensão em pacientes com acromegalia curada/controlada e com doença ativa. PACIENTES E MÉTODOS: Estudo transversal com 44 pacientes com acromegalia seguidos em nosso serviço. Eles foram submetidos a avaliação clínica, exames laboratoriais e ecocardiograma. Pacientes com doença curada/controlada foram avaliados como um grupo único e os indivíduos com doença ativa como outro grupo. RESULTADOS: Quarenta e sete por cento dos pacientes apresentaram acromegalia ativa. Esses indivíduos foram mais jovens e apresentaram níveis mais baixos de pressão arterial que os indivíduos com doença controlada/curada. A hipertensão foi detectada em 50 por cento da amostra. Indivíduos com doença ativa mostraram uma correlação positiva entre os níveis de IGF-1 e os níveis de pressão arterial sistólica e de pressão arterial diastólica (r = 0,48, p = 0,03; e r = 0,42, p = 0,07, respectivamente) e também apresentaram uma correlação positiva entre IGF-1 e excreção urinária de albumina (EUA). Em pacientes com doença ativa, o IGF-1 foi um preditor da pressão arterial sistólica, embora não tenha sido independente da taxa de EUA. Para indivíduos com doença curada/controlada, a circunferência da cintura e os triglicérides foram os preditores associados aos níveis de pressão arterial sistólica e diastólica. CONCLUSÕES: Nossos resultados sugerem que os níveis pressóricos em pacientes com acromegalia ativa dependem do excesso de GH. No entanto, uma vez que a doença torna-se controlada e os níveis de IGF-1 reduzem, os níveis de pressão arterial dependerão de outros fatores de risco cardiovasculares.

Sensibilidad diagnóstica de los distintos tiempos de la prueba de estímulo con clonidina, indicada para descartar deficiencia de hormona de crecimiento en niños con talla baja / Timing of growth hormone peaks during the clonidine provocation test

Background: Clonidine provocative test is used for the diagnosis of growth hormone (GH) deficiency. The duration of the test is not uniform across places where it is performed. Aim: To evaluate the frequency and timing of GH peaks during the clonidine test. To determine the timing with the highest diagnostic yield for GH deficiency. Patients and Methods: Analysis of the GH response during a clonidine test performed to 93 children with low stature, aged 11 +/- 3 years (41 percent women), with mean z scores of -2.3 +/- 0.8 for height and of 0.4 +/- 0.9 for body mass index, that were consecutively studied. A oral dose of 0.15 mg/m2 of clonidine was administered and GH levels were determined by the chemiluminescent enzyme immunoassay method of solid phase at 0, +30, +60, +90 and +120 minutes after. The cut-off point for GH deficiency was set at 7 ng/dL. Results: In ten children GH levels were lower than 7 ng/dL during the test and were considered as having GH deficiency. In 86 percent of the 83 patients without GH deficiency, the peak over 7 ng/mL appeared at +60 minutes and in 89 percent the peak had appeared at +90 minutes. In only 11 percent of these children, the peak appeared at +120 minutes. Conclusions: The timing with the highest diagnostic yield for GH is +60 minutes after the administration of clonidine. However the sample at +120 minutes should not be eliminated, considering that the highest GH peak appears at that time in 11 percent of children.

The role of insulin like growth factor (IGF)–1 and IGF-binding protein-3 in diagnosis of growth hormone deficiency in short stature children.

Objective. To evaluate the role of IGF-1 and IGFBP-3 in diagnosis of short stature children and adolescents in whom Growth Hormone Deficiency (GHD) was found. Methods. In this cross sectional study the referred short stature children and adolescents to Namazi Hospital in Shiraz- Iran, in 2003-2005 were studied. The inclusion criteria were proved short stature based on the physical examination, weight, height, standard deviation score (SDS) of height < -2 , with considering stage of puberty and predicted height in children without any genetic or chronic disorders. The exclusion criteria were any positive physical or laboratory data suggesting hypothyroidism, rickets or liver disorders. For all patients a provocative growth hormone test was performed with propranolol and L-dopa and serum IGF-1 and IGFBP-3 were measured. GHD defined as peak(cutoff ) serum GH level under 10 ìg/L and low IGF-1 and IGFBP-3 considered as cutoff serum level under -2 standard deviation. Results. Eighty one short stature patients (39 boys and 42 girls) with mean age of 10.6 ± 3.5 years completed the study. Seventeen patients with GHD were found and in 18 patients IGF-1 level were low. Only in 6 patients both GH and IGF-1 were low and 2 of them had low IGFBP-3. There were no correlations between the levels of GH,IGF-1 and IGFBP-3 in children with short stature due to GHD. The sensitivity and specifity of IGF-1 and IGFBP-3 in assessment of GHD were 35% and 81% for IGF-1 and 12% and 94% for IGFBP-3, respectively. Conclusion. No correlations were found between GH level and serum levels of IGF-1 and IGFBP-3 in short patients and the sensitivity of these tests in assessment of GHD was poor.

Influence of Gender on Serum Growth Hormone, Insulin-Like Growth Factor-I and Its Binding Protein-3 during Aging

PURPOSE: The serum concentrations of insulin-like growth factors-I (IGF-I), insulin-like growth factor binding protein-3 (IGFBP-3) and growth hormone (GH) are related to body composition, function and metabolism, and are influenced by the aging process. This study was to investigate the influence of gender on serum concentrations of IGF-I, IGFBP-3 and GH in middle and old age subjects. MATERIALS AND METHODS: Sixty healthy volunteers (male 35, female 25, 36-70 years) were divided into 50 years groups, based on gender. Women > 50 years were post-menopause. IGF-I, IGFBP-3, and GH were determined by immunoradiometric assay. RESULTS: IGF-I was shown to be negatively correlated with age (women r = -0.62, p 50 years showed a significant reduction in IGF-I values than women 50 years showed smaller IGF-I/IGFBP-3 molar ratios (0.177998 +/- 0.039404) than men of same age group (0.228326 +/- 0.050979, p < 0.01) and women < or = 50 years (0.247667 +/- 0.069411, p < 0.01). Age was shown to positively correlate with GH/IGF-I (r = 0.49, p < 0.05) and GH/IGFBP-3 ratios (r = 0.40, p < 0.05) in women. CONCLUSIONS: The influence of aging on serum concentrations of IGF-I is more remarkable in women than in men. Menopause causes reduction of IGF-I/IGFBP-3 molar ratio. Women have the trend of progressive hypoactivity of GH to stimulate IGF-I and IGFBP-3 secretions with age.