Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01275 (glucagon)
 26,492 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Iron overload was produced in Wistar rats by repeated intraperitoneal injections of ferric nitrilotriacetate (Fe(3+)-NTA) for one to six months. Pancreatic tissues from these iron-overloaded rats and untreated controls were examined for insulin (for B cells), glucagon (for A cells), transferrin receptor (TfR), transferrin (Tf) and ferritin (Ft) using immunohistochemical methods, and for iron by histochemical Berlin blue staining. In the islets of iron-overloaded rats, increased Ft staining appeared prior to deposition of Berlin blue-stainable iron, and the staining intensity of Ft and iron was stronger in B cells than in A cells. In the islets of untreated control rats, the staining intensity of TfR was stronger in B cells than in A cells. TfR staining of the islets was weaker in iron-overloaded rats than in the controls. These findings suggest that 1) iron uptake by islet cells in vivo is regulated and mediated by TfR, 2) intracytoplasmic Ft transforms into stainable iron in iron-overloaded rats, and 3) predominance of TfR expression in B cells may result in selective deposition of iron and predispose B cells to damage and diabetes mellitus in iron-overloaded rats.
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PMID:Transferrin receptors and selective iron deposition in pancreatic B cells of iron-overloaded rats. 177 64

Transferrin mRNA content and gene transcription rate were measured in the liver of rats submitted to iron overload or depletion, castration, treatment with sexual steroid hormones, glucagon and cyclic AMP. The influence of puberty in males and females and of pregnancy was also analysed. Glucagon and cyclic AMP reduced mRNA level by about 50% at the 12th hour of treatment and transferrin gene transcription by as much as 95% at the 30th minute of drug infusion, with a secondary increase of the transcription rate for a protracted treatment. None of the other hormones tested had any detectable effect on transferrin gene expression, the same being true for iron overload or depletion.
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PMID:Transient transcriptional inhibition of the transferrin gene by cyclic AMP. 286 86

Fifty healthy and 12 thalassaemic subjects underwent both an oral glucose tolerance test (OGTT) and arginine test in order to investigate their alpha and beta cell activity. While basal plasma levels were similar in both group of subjects (82 +/- 4 vs 74 +/- 4 mg/dl, p = NS), following glucose intake impaired glucose tolerance was observed in thalassaemic subjects. These subjects showed impaired insulin secretion either in steady-state conditions or after glucose intake. When an arginine test was performed in thalassaemic subjects, impaired insulin secretion with concomitant exaggeration of glucagon response was also observed. In the thalassaemic subjects no statistically significant correlations were found between impaired insulin secretion and iron overload. It is suggested that in thalassaemic subjects beta-cell dysfunction and alpha cell overactivity may lead to the development of diabetes mellitus.
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PMID:Role of alpha and beta cells in the impaired glucose tolerance of thalassaemic subjects. 331 64

Insulin, glucagon, somatostatin and pancreatic polypeptide cells were quantified after immunoperoxidase staining in sections of pancreases obtained from nine control subjects and seven diabetic patients with primary or secondary iron overload. One was normoglycaemic, two had glucose intolerance and four presented insulin-requiring diabetes. The whole pancreas was studied, taking into account the heterogeneous distribution of the endocrine cells. In the diabetic patients, the weight of the pancreas tended to be lower. Iron overload predominated in the exocrine tissue, whereas in islets iron concentration was quite variable from case to case. At the Haemalun-Eosine staining the histological appearance of the islets was normal, their shape and size being unchanged; amyloid deposits were absent, as were atrophic islets. Immunoperoxidase staining revealed a severe reduction in the number of immunoreactive B cells in the four diabetic patients. The mass of immunoreactive B cells was calculated from their volume density and from the weight of each lobe of the pancreas. It averaged 950 mg in control subjects, 1580 mg in the normoglycaemic patient, 1010 mg in patients with glucose intolerance and 180 mg in insulin-requiring diabetic patients. The electron microscopic examination, performed in four cases, revealed that the iron deposits were restricted to B cells and associated with progressive loss of their endocrine granules. The study shows that the pancreatic islet abnormalities in iron overloaded diabetic patients are completely different from those of Type 1 (insulin-dependent) and Type 2 (non-insulin-dependent) diabetic patients. This constitutes a further argument for a specific role of iron in the pathogeny of diabetes in haemochromatotic patients.
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PMID:The haemochromatotic human pancreas: a quantitative immunohistochemical and ultrastructural study. 355 22

Insulin and glucagon secretion were studied during an oral glucose tolerance test and arginine infusion in 11 patients with thalassaemia intermedia, who showed laboratory evidence of iron overload. Mean blood glucose concentrations in patients with thalassaemia intermedia were significantly higher than normal and 3 of 11 patients had impaired glucose tolerance. The principal abnormality appears to be a deficiency in insulin and glucagon from the pancreas in response to oral glucose tolerance and arginine stimulation tests. Several factors, such as iron overload, chronic hypoxia, zinc deficiency and increased catecholamine production secondary to anaemia, might play a part in the pathogenesis of these abnormalities. Each of these factors affect individual cases to a varied degree. Our data emphasize the mildness of carbohydrate defect as compared to the degree of insulinopenia and indicate the necessity for prescribing measures which prevent excessive iron deposition and improve iron excretion in thalassaemic patients with iron overload.
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PMID:Alpha and beta cell evaluation in patients with thalassaemia intermedia and iron overload. 390 15

Hepatic and pancreatic damage owing to iron overload is often present in patients with beta-thalassemia major. In order to investigate B-cell function and hepatic insulin clearance in these patients, under a high transfusion program and regular chelation therapy, we studied the glucose (BG), insulin (IRI) and C-peptide (CPR) response and the CPR/IRI ratio after OGTT in 27 patients with Cooley's anemia and in 10 sex- age- and weight-matched healthy subjects; we also studied BG and IRI levels after IVGTT in 9 beta-thalassemic patients and in 9 control subjects. Furthermore, BG, CPR, IRI and glucagon (IRG) response to arginine infusion were evaluated in 5 thalassemic patients with normal OGTT and in 5 age-, sex- and weight-matched normal children, in order to assess pancreatic A-cell function, too. OGTT and IVGTT were normal in the patients with beta-thalassemia major. Plasma IRI level 30 min after an oral glucose load and the insulinogenic index for cumulative intervals were significantly lower in thalassemics after OGTT, whereas the insulin response and insulinogenic index were normal following i.v. glucose. No significant difference was observed for the CPR/IRI ratio during OGTT between thalassemics and normal subjects. Finally, BG, CPR, IRI and IRG levels were similar in the thalassemic patients and in healthy children both fasting and following arginine infusion. Our data suggest that patients with beta-thalassemia major, under a high transfusion program and regular chelation therapy, may have normal glucose tolerance and normal hepatic insulin clearance in spite of iron overload in pancreas and liver. Insulin response to oral glucose was lower than the one to IVGTT, probably because of diminished secretion of the gastrointestinal hormones which stimulate insulin release.
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PMID:Study of A- and B-cell function in beta-thalassemia major. 634 2

Severe autoimmune haemolytic anaemia in a five year old boy was unaffected by treatment with prednisone and splenectomy, but subsided after combined immunosuppressive therapy and three plasma exchanges. Over five months, a total of 93 transfusions of concentrated erythrocytes was given (equal to 18.6 grams of iron or 1.1 g/kg BW). This resulted in severe iron overload with cardiac, hepatic, and pancreatic complications, together with growth-retardation. These complications disappeared after treatment with desferrioxamine and vitamin C, but despite a normal growth hormone response to glucagon the concentration of somatomedin in serum remained low. Treatment by plasma exchanges and immunosuppressive agents may therefore be of value in severe haemolytic anaemia refractory to corticosteroids and splenectomy. Iron chelating therapy should be considered if multiple transfusions result in iron overload.
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PMID:Autoimmune haemolytic anaemia treated with multiple transfusions, immunosuppressive therapy, plasma exchange, and desferrioxamine. 670 46

Disturbances of growth and development in patients with thalassaemia receiving hypertransfusion programmes are well recognised and are most likely to be due to iron overload. The extent of endocrine dysfunction was investigated in a group of 18 patients thought to have been treated by acceptable modern standards, 11 of whom could be considered as well chelated. Assessment of growth and puberty showed a wide variation in height SD scores with five patients having significantly short stature. Most patients are progressing through puberty normally with the exception of two boys with marked pubertal delay. The most prominent finding was that growth hormone responses to glucagon stimulation were significantly impaired in all of the patients with iron overload. Basal endocrine assessment showed primary hypothyroidism in two patients aged 16.8 and 12.9 years with plasma thyroxine-concentrations of 86 and 59 nmol/l (normal range 65-165 nmol/l) and plasma thyroid stimulating hormone 10.2 and 30.3 mU/l (normal range 0.5-5 mU/l). One patient had diabetes mellitus. These results show that even when ideal management is sought a significant amount of endocrine damage occurs; surveillance of these patients is thus essential.
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PMID:Relationship of endocrinopathy to iron chelation status in young patients with thalassaemia major. 794 32

Hypertransfusion therapy has dramatically increased the duration and quality of life in patients with B-thalassemia major; however, it leads to chronic iron overload, and is frequently complicated by the development of diabetes mellitus or impaired glucose tolerance. To determine the early effect of iron overload on the endocrine pancreatic function, we studied glucose, insulin, and glucagon responses to oral load of glucose and to arginine provocation in 15 children with B-thalassemia major, before and after (3.1 +/- 0.6 years) high-transfusion and iron chelation and compared them with 15 age matched normal controls. In addition, we evaluated growth hormone (GH) responses to oral clonidine and measured the circulating insulin-like growth factor-I concentration in thalassemic children on long-term transfusion and controls. After long-term high-transfusion, thalassemic children had significantly decreased serum insulin concentrations and low insulin/glucose ratios at 60 and 120 min after an oral glucose load (1.75 g/kg) in comparison with values before therapy and those for controls. None of the thalassemic children had glucose intolerance after this period of frequent blood transfusion; however, their serum glucose levels at 60 and 120 min after the oral glucose load were significantly higher compared to control children. Thirty minutes after starting arginine infusion, serum insulin concentration was significantly lower in thalassemic children compared to before therapy. Basal and arginine-stimulated glucagon secretions were significantly elevated in thalassemic children on long-term blood transfusion with significantly low serum insulin/glucagon ratios. In addition, the high basal serum glucagon concentrations were not suppressed after the oral glucose load. Despite hyperglucagonaemia in all thalassemic children, their blood glucose dropped appropriately below 50 per cent of the fasting glucose level after an intravenous insulin dose (0.1 U/kg) ruling out any significant insulin-resistance. GH responses to clonidine provocation were subnormal in thalassemic children after long-term blood transfusion compared to controls. In summary, thalassemic children on long-term blood transfusion and iron chelation have progressive and early loss of B-cell mass, manifested by decreased insulin release in response to secretagogues, before the development of significant insulin resistance or impairment of glucose tolerance.
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PMID:Insulin and glucagon responses to provocation with glucose and arginine in prepubertal children with thalassemia major before and after long-term blood transfusion. 893 61

Serum insulin, and plasma glucagon and glucose levels were measured in 56 Chinese patients with aplastic anemia (AA) and 40 normal controls. Serum insulin and plasma glucose levels in 18 newly diagnosed cases and 11 previously treated cases with prednisone were significantly higher than those in the controls. Serum insulin and plasma glucose levels in 27 cases previously treated with stanozolol were significantly higher than those in the newly diagnosed cases and the previously treated cases with prednisone. There was no significant difference in plasma glucagon levels between the patients and the controls. Serum insulin and plasma glucose levels were significantly correlated with the amount of blood transfusions and serum ferritin and cortisone concentrations in the AA patients. Our findings suggest that AA patients may have hyperinsulinemia accompanying hyperglycemia, which can be further aggravated by stanozolol and prednisone therapy and iron overload.
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PMID:Hyperinsulinemia accompanying hyperglycemia in Chinese patients with aplastic anemia. 937 26


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