Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P02794 (ferritin)
 17,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In screening a rat pancreatic islet cDNA library by differential hybridization for transcripts increased by glucose, the H chain of ferritin, an iron storage protein, was identified. An ELISA for rat ferritin showed that the insulin cell contains a surprisingly high amount of ferritin comparable to that of iron storage tissues. Most of the ferritin was located in the beta cell, as judged from colocalization of ferritin and insulin by immunohistochemical staining of the pancreas. Islets maintained for 24 h in culture medium containing 20 mM glucose are capable of releasing insulin in response to stimulation with glucose, but islets maintained at 1 mM glucose are incapacitated in response to glucose (see ref 1). Immunoassayable ferritin was threefold higher in 20 mM glucose islets than in 1 mM glucose islets and the glucose-stimulated increase in H ferritin mRNA was confirmed by probing Northern blots of islet RNA with authentic H and L chain cDNAs. This showed that H ferritin mRNA was four- to eightfold higher in 20 mM-glucose islets than in 1 mM glucose islets, whereas L ferritin mRNA was decreased 75-90% in 20 mM glucose islets relative to 1 mM glucose islets. The physiological reason for the abundance of (apo)ferritin in the beta cell is not readily apparent because the islet contains very little iron. Whether or not ferritin is used to handle another metal such as zinc, which is plentiful in the beta cell, is unknown. Another potential reason for ferritin in the beta cell is that ferritin has antioxidant properties and the beta cell is particularly sensitive to oxygen radicals. Regardless of its physiologic purpose, the high amount of ferritin can explain why iron is preferentially retained in the insulin cell and causes diabetes in diseases of iron overloading.
 ...
PMID:Large amount of (apo)ferritin in the pancreatic insulin cell and its stimulation by glucose. 805 Jun 78

An elevated serum ferritin concentration recently has been shown to be associated with coronary artery disease and its risk factors, including blood glucose concentration. The purpose of this study is to establish the prevalence of elevated levels of serum ferritin in patients with non-insulin-dependent diabetes mellitus (NIDDM) without hemochromatosis and to determine whether or not deferoxamine is of therapeutic value in treating such patients. The level of serum ferritin was measured in consecutive eligible patients with NIDDM seen at routine outpatient visits. Five patients with an elevated serum ferritin were treated with deferoxamine, 1 g intramuscularly, twice a week for 12 weeks. The level of serum ferritin was measured every 4 weeks, and the level of glycosylated hemoglobin was measured at baseline, at the end of the treatment, and 12 weeks after treatment was completed. The level of serum ferritin was elevated in 34 of 102 (33%) patients with NIDDM. The level of serum ferritin remained elevated in 30 of 32 (94%) of these patients on repeat testing. In three of the five patients treated with deferoxamine, the level of serum ferritin was normalized, but no patient had an appreciable change in dosage of medication for diabetes or glycemic control. Non-insulin-dependent diabetes is a condition frequently associated with elevated levels of serum ferritin. Treatment with deferoxamine intramuscularly was not effective in improving control of glucose in our patient group.
 ...
PMID:Non-insulin-dependent diabetes mellitus and elevated serum ferritin level. 821 68

The ES 300 system, a fully automated multichannel immunoassay analyzer, was evaluated simultaneously for 9 weeks in four major centers. Precision, accuracy, carryover, comparison to in-house methods, and interferences were assessed for the following 17 tests: T4, T3, FT4, TSH, TBK, TBG, LH, FSH, prolactin, HCG, digoxin, cortisol, ferritin, IgE, insulin, AFP, and CEA. All centers reported good intra-lab and inter-lab precision. Accuracy was judged to be good based on correlation with in-house methods and recovery of target values in commercial and proficiency control materials. Linearity was evaluated for 14 analytes. Method biases were observed for T3 and insulin that were attributed to differences in standardization. No significant interferences from bilirubin, lipemia, and hemolysis were observed for all methods except insulin and AFP. Featuring random access capability, low daily maintenance, and high throughput, the ES 300 system performed well and met the stated claims of the manufacturer.
 ...
PMID:A multicenter evaluation of the Boehringer Mannheim ES 300 immunoassay system. 844 40

Deferoxamine has been proposed as a potentially important therapy for individuals with NIDDM and mild elevations in serum ferritin. Previously, iron chelation therapy with intravenous deferoxamine over a 5-13-wk period has been reported to normalize serum ferritin and markedly improve glycemic control. To confirm these results and to study potential beneficial effects of deferoxamine on insulin secretion, 9 individuals with NIDDM and elevated serum ferritin levels were treated twice weekly with deferoxamine infusion, following a previously described protocol. Although 8 of 9 subjects achieved normal or near-normal serum ferritin values after deferoxamine therapy, we found little evidence that it produced beneficial effects on glycemic control. Fasting glucose levels pre- and post-deferoxamine therapy were unchanged (11.6 +/- 1.2 and 11.3 +/- 1.5 mM, respectively, P = 0.80). GHb levels declined slightly after deferoxamine therapy (9.3 +/- 0.7 vs. 8.8 +/- 0.7%, P < 0.05); however, this effect was small and was not associated with elimination of or even substantial reduction in insulin or oral hypoglycemic therapy. Deferoxamine therapy did not significantly alter fasting insulin or C-peptide levels, nor stimulated insulin or C-peptide responses to intravenous arginine or glucose. During follow-up studies 1.5-8 mo after deferoxamine therapy, serum ferritin levels again were elevated in 5 of 8 subjects who showed an initial response. Thus, although deferoxamine therapy reduced serum ferritin levels in our subjects, we were unable to confirm a previous report that this effect was associated with any meaningful improvement in glycemic control or insulin secretion.
 ...
PMID:No effect of deferoxamine therapy on glucose homeostasis and insulin secretion in individuals with NIDDM and elevated serum ferritin. 845 4

Glucose intolerance is a common consequence of transfusion therapy in patients with thalassemia major (TM), but the relative contribution of pancreatic damage and insulin resistance to glucose intolerance is unclear. We have investigated oral (OGTT) and intravenous (IVGTT) glucose tolerance, insulin sensitivity, and fasting concentrations of insulin, proinsulin, and des 31,32 proinsulin in 12 patients with TM (seven hepatitis C virus [HCV] antibody-negative and five-positive), eight patients with hepatic cirrhosis, and nine healthy controls. Two-hour plasma glucose concentrations were marginally higher in anti-HCV-negative (median, 7.4 mmol/ L; range, 4.0 to 8.2) and significantly so in anti-HCV-positive thalassemics (median, 8.5 mmol/L; range, 6.4 to to 23.0) and cirrhotics (median, 8.0 mmol/L; range, 4.7 to 17.6) than in controls (median, 5.5 mmol/L; range, 3.0 to 6.3). Insulin sensitivity was also reduced in the three patient groups (P < .05). Insulin resistance was the main determinant of oral glucose intolerance in all patient groups (partial r2 = .49, P < .0001, n = 28). In turn, the main determinants of insulin insensitivity in TM patients were liver damage (albumin, r = .67, P = .02) and serum ferritin concentration (r = -.62, P = .03). There was no relationship of either 2-hour or incremental insulin concentrations with ferritin levels or with HCV status in TM subjects. Moreover, these patients showed no elevation of concentrations of proinsulin and des 31,32 proinsulin, markers of pancreatic beta-cell damage, in excess of those observed in cirrhotic patients. In conclusion, the glucose intolerance of TM, like that of cirrhosis, is associated with insulin resistance, not insulin deficiency, and may be a direct or indirect consequence of hepatic damage.
 ...
PMID:Glucose intolerance in thalassemia major is related to insulin resistance and hepatic dysfunction. 862 11

The endocrine function was studied in 9 hemodialysis patients with iron overload (IO) before and after iron depletion. Diagnosis of IO was established by high serum ferritin (> 1100 micrograms/L), high hepatic CT density (> 70 Hounsfield units), and excessive iron stores in bone marrow aspirate (grade 6). At the start of the study, 8 patients had gonadal failure, 6 of whom had hypothalamopituitary disease, and 4 manifested thyroid abnormalities. At the end of the study, the hypothalamopituitary function and thyroid abnormalities improved in all patients except one who manifested hypothalamic disease. Primary gonadal failure persisted in the 8 patients. ACTH stimulation produced adequate increments in plasma cortisol at the start and end of the study. Pancreatic (beta cell) function was adequate at the end of the study as shown by normal oral glucose tolerance test and free insulin increments during the test. The CT scan and follow-up indicated significant iron mobilization from the liver, pancreas, and the adrenal glands. Hormonal studies were repeated in 4 of the 5 patients who manifested endocrine abnormalities and had received recombinant human erythropoietin (rHuEPO), 3 mo after discontinuation of the drug. Improvement in the endocrine function persisted in those patients. Our results indicated that dialysis patients exposed to iron overload are at risk for development of multiple endocrine defects. Fortunately, aggressive iron depletion can mobilize iron from these organs and reverse some of the defects.
 ...
PMID:Endocrine abnormalities in hemodialysis patients with iron overload: reversal with iron depletion. 874 13

We evaluated tobacco use, physical activity, dietary intake and cardiovascular risk indicators (s-lipids, s-insulin, s-ferritin, anthropometric measurements, blood pressure, physical fitness) in healthy 14- and 17-year-old Swedish adolescents in relation to socio-economic status (SES) of their parents. Girls reported more smoking than boys (14-year-olds 10 and 3%, 17-year-olds 27 and 18%, girls and boys, respectively). Daily smoking was associated to low SES of the family, but was most strongly associated to smoking in peers (OR = 58.7). Tobacco use was considerably higher among adolescents attending vocational programs at secondary high school as compared with theoretical programs. Daily smokers had a more unfavourable serum lipid profile compared with non-smokers. Adolescents from families with a low educational level of the mother had a higher relative dietary fat intake. Boys and girls from families of low SES had higher body mass index (BMI), and girls, but not boys, also had lower physical fitness. Clustering of high BMI, low physical fitness and daily smoking was more pronounced in girls from families of low SES. In conclusion, our study shows that in both boys and girls low SES and educational level of the parents are related to an unfavourable cardiovascular risk profile in Swedish adolescents. Furthermore, smoking in adolescents is more related to smoking in peers than to smoking in parents, implying that preventive efforts should focus on peer groups.
 ...
PMID:Cardiovascular risk indicators cluster in girls from families of low socio-economic status. 888 23

Ten patients (18 +/- 1 yr) on chronic hemodialysis (HD) with anemia were studied before and after treatment with erythropoietin (EPO) for 9 mo. Six patients had evidence of iron overload (serum ferritin over 300 ng/ml; group I) and the other four patients (serum ferritin below 300 ng/ml; group II) did not. Before treatment, both groups of patients were glucose tolerant but insulin resistant and hyperinsulinemic. There was equal correction of anemia but no significant changes in serum biochemistry (apart from iron studies) or anthropometric measurements in both groups. With amelioration of anemia and iron overload in group I, insulin sensitivity increased by 53% to within normal values. Insulin secretion also normalized. With amelioration of anemia but no change in iron status in group II, insulin sensitivity (increased by 60%) and insulin secretion also normalized. Thus correction of anemia by EPO reversed insulin resistance and hyperinsulinemia in HD patients with or without iron overload. The effects of correction of anemia rather than iron overload may be more important in the pathogenesis of insulin abnormalities in end-stage renal disease.
 ...
PMID:Correction of anemia by erythropoietin reverses insulin resistance and hyperinsulinemia in uremia. 892 46

Available evidence suggests that glucose, the most potent physiologic insulin secretagogue, capacitates glucose-induced insulin secretion by stimulating synthesis of various proteins in the beta cell. To obtain more clues about proteins that might be involved in insulin secretion, rat pancreatic cDNA libraries were screened by differential hybridization for non-preproinsulin transcripts that were increased when pancreatic islets were cultured for 1 day at a high (20 mM) versus a low concentration (1 mM) of glucose. More than 100,000 pfu were initially screened. After repeated rescreening, 33 transcripts were 1-3-fold higher in the presence of the high glucose. For comparison, preproinsulin transcripts were 4-8-fold higher at the high concentration of glucose. The sequences of 12 clones were > or = 85% similar to published sequences. These included annexin, calbindin, protein kinase C receptor, the G protein beta subunit, the guanyl cyclase A/atrial natriuretic peptide receptor and the serotonin 5HT-2 receptor. As previously reported, ferritin H chain transcripts were discovered to be 3-6-fold higher in the presence of the high glucose (MacDonald et al., FASEB J. 8, 777-781, 1994). Unidentified glucose responsive clones have been assigned GenBank accession numbers N55606-N55636, N65938 and N65939. The results implicate the proteins encoded by these mRNAs in insulin secretion.
 ...
PMID:Glucose-stimulated expressed sequence tags from rat pancreatic islets. 896 Dec 57

Elevated serum ferritin concentrations between 200 and 500 microg/l have been found to be a strong risk factor for acute myocardial infarction in Finnish men, but the reason for this association is still uncertain. In the Finnish population ferritin concentrations correlated with factors of insulin resistance syndrome. As these factors have been found to be associated with an LDL subfraction phenotype of increased concentrations of small, dense LDL particles, we hypothesized an association between ferritin and an atherogenic LDL subfraction profile, a finding which could be an explanation for the observed relationship between ferritin and atherosclerosis. Therefore we determined serum ferritin levels, metabolic cardiovascular risk factors, and the LDL subfraction phenotype in 93 healthy men without signs for infection or coronary heart disease. We found that men with moderately elevated ferritin levels (200-500 microg/l; n = 31) had a significantly worse coronary risk profile than men with lower levels ( < 200 microg/l; n = 62). Elevated ferritin concentrations were associated with significantly higher values for serum triglycerides, VLDL cholesterol, VLDL apolipoprotein B (P < 0.01), IDL cholesterol, fasting glucose (P < 0.05) and uric acid (P < 0.01), and lower levels for HDL2b and HDL2a cholesterol and apolipoprotein A-I (P < 0.05), and lipoprotein(a) (P < 0.01). Elevated ferritin levels were, however, not associated with an unfavourable LDL subfraction profile of increased concentrations of small, dense LDL particles.
 ...
PMID:Relationship of serum ferritin concentrations with metabolic cardiovascular risk factors in men without evidence for coronary artery disease. 905 Jul 80


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>