All levels of the growth hormone (GH), GH binding protein (GHBP), insulinlike growth factor (IGF) and IGF binding protein (IGFBP) axis are influenced by chronic hypercortisolism. Thus, there is a blunted response to GHRH alone or together with other stimuli associated with a marked suppression of endogenous GH secretion but accompanied by normal GHBP, normal to low IGF-1 and GHBPs 1 and 3 with the correspondent 41.5 and 38.5-kD molecular forms of the latter presenting values similar to normal. These findings may suggest enhanced GH sensitivity with normal or increased IGF-1 bioavailability to the correspondent tissue receptors. In conclusion, the glucocorticoid (GC)-induced target tissue resistance can neither be attributed to the suppression of the GH axis nor to changes in circulating GHBPs 1 and 3. However, it may be related either to the described 12- to-20-kD inhibitor(s) which antagonizes postbinding IGF-1 bioactivity (gene expression) and/or by the downmodulation of activator protein-1 (Fos/Jun) activity by the GC-GC receptor complex.
This paper reports a case of XY gonadal dysgenesis in two sisters. Both patients presented an eunochoid female phenotype with normal external genitalia. At laparotomy, the elder sister was found to have bilateral gonadoblastoma. Cytogenetic studies, which included G and C banding and in situ hybridization, showed that the patients had an apparently normal 46, XY karyotype. PCR analyses revealed absence of the conserved portion (HMG box) of the SRY gene and of the Y chromosome pseudoautosomal boundary region sequence in both patients. The presence of the ZFY sequence was detected by Southern hybridization in the two affected sisters. The patients' father (46, XY, no mosaicism detected in peripheral blood lymphocytes) was positive for SRY and ZFY sequences. The occurrence of gonadoblastoma is discussed in terms of the genetic factors that may lead to tumor development.
GH secretion in normal subjects is periodic, with pulses prevailing during sleep. During the day (basal secretion), GH levels are, in general, undetectable. We studied GH secretion by cluster analysis, collecting samples every 20 min for 24 h in 44 subjects: 11 patients with active acromegaly; 16 "cured" acromegalics, and 17 normal subjects. The purpose of this study was to compare GH secretion between patients with active acromegaly and "cured" patients and between "cured" acromegalic patients and normal controls. The number of pulses detected through the 24-h GH profile was not different between acromegalic patients regardless of disease activity (17.5 +/- 4.4 vs. 15.0 +/- 6.0, respectively), but was different when active acromegalic patients and normal controls were compared (8.1 +/- 1.0; P < 0.05) and when cured acromegalic patients and normal controls were compared (P < 0.05). The GH pulsatile secretion/total GH secretion ratio was higher in normal controls than in acromegalic patients regardless of disease activity. We concluded that 1) the increases in GH pulsatility in active and cured acromegalic patients are similar, but most of the 24-h GH secretion is nonpulsatile; 2) half of the GH secretion in normal subjects occurs during pulses; 3) cured acromegalic patients, even those with normal GH and insulin-like growth factor I levels, do not recover a normal GH secretory pattern.
Growth hormone (GH) secretion disorders have been reported in poorly controlled type I diabetes mellitus patients. Our work was aimed to evaluate GH secretion in 9 type I young diabetes mellitus patients as well as the low molecular weight IGF-binding protein secretion (IGFBP-1) in 5 of them. The patients did not show any signs of malnutrition or neurovascular complications, neither were they on any medication except for insulin. The study protocol included blood samples collection during a 24-h period for measurement of glucose, glycated hemoglobin, GH IGF-I and IGFBP-1 levels under two situations: on poor glycemic control and after 2-3 months on better control through systematic diet, low in carbohydrates and increase in insulin dosage. GH secretion data were analyzed by Cluster algorithm for pulsatility parameters; for rhythm assessment Cosinor method was used. The first study (poor control) reported significant increase of GH maximal and incremental amplitude and duration pulse values, when compared to the second study (better control). Mean 24-h secretion values as well mean GH for interpulse intervals (valleys) decreased, although not statistically significant. The fraction of pulsatile GH/24 h GH did not change significantly with better glycemic control. No changes in pulse frequency were observed. Mean IGF-I concentrations were significantly higher when patients were on better glycemic control. An ultradian variation for GH secretion was noticed in the first study (poor control) and a circadian variation in the second one (better control). IGFBP-1 analysis showed significant decrease of the mean 24-h values under better glycemic control. Linear regression analysis demonstrated a correlation between IGFBP-1 levels and fasting glucose levels. A circadian variation was present in IGFBP-1 secretion, irrespective of glycemic control. Therefore, we concluded that for type I diabetic patients: 1. GH secretion is increased on poor control, through maximal, incremental amplitude and pulse duration values; 2. IGFBP-1 values were significantly reduced and IGF-1 levels significantly higher after better glycemic control; 4. GH ultradian secretion is reported on poor control, and circadian on the better one, 5. IGFBP-1 circadian secretion occurred irrespective of glycemic control.
Objective: To assess the plasma levels and action of arginine vasopressin (AVP) in patients with Cushing's disease. There are many reports that patients with Addison's disease have increased AVP levels associated with hyponatraemia and hypoosmolality, but none on the dynamics of secretion of this neurohormone during osmolality-based stimulation in patients with chronic hypercortisolism. Design and subjects: The plasma AVP concentration and the urinary and plasma osmolality after a 7.5-h water deprivation test (WDT) were evaluated in 13 patients with Cushing's disease and 15 normal (control) individuals. In patients with Cushing's disease we also assessed the urinary osmolality in response to 10 mg i.v. desmopressin (DDAVP) administered at the end of the WDT. Results: At the end of the WDT, urinary osmolality was significantly lower in patients with Cushing's disease (511.5Ϯ148.5 mOsm/l) than in the normal subjects (981.1Ϯ107.1 mOsm/l, P<0.001), whereas plasma osmolality did not differ between the two groups. Consequently, the urine/plasma osmolality ratio (U osm /P osm ) was lower in patients with Cushing's disease than in normal individuals (1.8Ϯ0.5 compared with 3.4Ϯ0.4, P<0.001). The AVP concentration also was greater (7.3Ϯ3.1 pmol/l) in those with Cushing's disease than in the controls (3.9Ϯ2.3 pmol/l, P<0.005). After administration of DDAVP to the hypercortisolaemic patients, the urinary osmolality attained (718.0Ϯ200.0 mOsm/l) was still lower than that in the normal group at the end of WDT (P<0.005). Conclusions: Patients with Cushing's disease presented higher AVP levels and smaller U osm /P osm ratios than normal subjects. After DDAVP, the patients with Cushing's disease were unable to concentrate the urine adequately. These data suggest that the kidney shows resistance to the action of both endogenous and exogenous AVP in patients with Cushing's disease.
SUMÁRIOEm decorrência do hiperinsulinismo endógeno (HHE), a hipoglicemia é diagnosticada em um indivíduo sintomático com níveis baixos de glicose plasmática, concomitante a valores elevados de insulina plasmática e peptídeo-C. Entre as causas de HHE, estão as doenças das células-b das ilhotas pancreáticas, o uso de secretagogos e a hipoglicemia autoimune. Neste artigo de revisão, estudamos 24 pacientes com hipoglicemia decorrente de hiperinsulinismo endógeno com a finalidade de descrever os aspectos de diagnóstico e tratamento. Nosso estudo mostrou que, após a realização do teste de jejum de 12h (minijejum) em três dias diferentes, todos os pacientes preencheram os critérios diagnósticos de HHE. Adicionalmente, encontramos que 11 dos 12 pacientes (91,7%) que realizaram o teste do glucagon apresentaram níveis de glicose no tempo 120 minutos menores que 50 mg/dL e inferiores ao valor basal. O teste do minijejum (3 amostras) e o teste do glucagon poderiam ser úteis para evitar a realização do jejum prolongado no diagnóstico do hiperinsulinismo endógeno. Arq Bras Endocrinol Metab. 2012;56(2):83-95 Descritores Hiperinsulinismo; insulinoma; hipoglicemia; pâncreas SUMMARY Hypoglycemia due to endogenous hyperinsulinism (EH) is diagnosed in a symptomatic patient with low levels of plasma glucose concomitant with elevated plasma insulin and C-peptide. Causes of EH are pancreatic islet-cells disease, use of insulin secretagogues, and autoimmune hypoglycemia. In this review, the authors studied 24 patients with hypoglycemia due to endogenous hyperinsulinism in order to describe aspects of diagnosis and treatment. Our study demonstrated that after 12 hours of fasting (mini-fasting test; at least three samples), all patients presented the diagnostic criteria for EH. Additionally, we found that 11 of 12 patients (91.7%) who underwent glucagon test achieved glucose levels less than 50 mg/dL and below baseline after 120 minutes. Mini-fasting (3 samples) and glucagon test may be useful to prevent prolonged fasting test to clarify the diagnosis of endogenous hyperinsulinism. Arq Bras Endocrinol Metab. 2012;56 (2) INTRODUÇÃOA glicose é um substrato metabólico fundamental para o cérebro, sendo a prevenção e a correção da hipoglicemia fundamentais para a manutenção da vida (1). A hipoglicemia pode ser dividida em pós-prandial (até 5h após a refeição) e de jejum e seu diagnóstico se baseia na presença da tríade de Whipple (glicose plasmática baixa, sintomas compatíveis com hipoglicemia e melhora dos sintomas após o aumento nas concentrações de glicose), cuja presença deve impelir à análise de suas potenciais causas, sendo essa investigação fortemente recomendada (2,3). Entretanto, o diagnóstico é praticamente inequívoco mesmo na ausên cia de sintomas se os valores de glicose plasmática estiverem abaixo de: 50 mg/dL na idade adulta e na adolescência (4,5), 40 mg/dL na criança pré-púbere (6), 30 mg/dL no neonato a termo e 20 mg/dL no neonato prematuro e/ou pequeno para a idade gestacional (7). EnCorrespondência para:
Nodular corticotrope hyperplasia is a rare pathology causing Cushing's syndrome owing to a primary pituitary disease or ectopic CRH production. In this study, we evaluated the laboratory and pathological findings and results of transsphenoidal pituitary surgery in four patients with Cushing's disease. Dynamic tests of pituitary-adrenal function (dexamethasone suppression, metyrapone, CRH, and DDAVP tests) were done before and after transsphenoidal pituitary surgery. Plasma and total urinary cortisol, serum 11-deoxycortisol, and plasma ACTH were determined by RIA. Hormonal dynamic tests and radiologic studies were compatible with a pituitary ACTH source. The transsphenoidal surgery revealed the presence of corticotrope hyperplasia confirmed by immunoperoxidase stain and a preserved reticulum framework in the removed pituitary tissue of these four patients. The pituitary surgery led to a short period of improvement in two of the patients (1 and 4), a 3-yr remission in one patient (patient 2), and no improvement in one (patient 3). We conclude that although our patients appear to have inadequate suppression with high-dose dexamethasone, there is no way to diagnose this pathology presurgically, and that total hypophysectomy, bilateral adrenalectomy, and irradiation are the only alternatives for definitive treatment. A CRH-secreting ectopic tumor could not be found in our patients either before or after surgery in the follow-up period.
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