Search results for "glucose uptake"
showing 10 items of 44 documents
Glycolytic phenotype and AMP kinase modify the pathologic response of tumor xenografts to VEGF neutralization.
2011
Abstract VEGF antagonists are now widely used cancer therapeutics, but predictive biomarkers of response or toxicity remain unavailable. In this study, we analyzed the effects of anti-VEGF therapy on tumor metabolism and therapeutic response by using an integrated set of imaging techniques, including bioluminescence metabolic imaging, 18-fluorodeoxyglucose positron emission tomography, and MRI imaging and spectroscopy. Our results revealed that anti-VEGF therapy caused a dramatic depletion of glucose and an exhaustion of ATP levels in tumors, although glucose uptake was maintained. These metabolic changes selectively accompanied the presence of large necrotic areas and partial tumor regress…
Glucose uptake in germinating Aspergillus nidulans conidia: involvement of the creA and sorA genes
2003
d-Glucose uptake in germinating wild-typeAspergillus nidulansconidia is an energy-requiring process mediated by at least two transport systems of differing affinities for glucose: a low-affinity system (Km∼1·4 mM) and a high-affinity system (Km∼16 μM). The low-affinity system is inducible by glucose; the high-affinity system is subject to glucose repression effected by the carbon catabolite repressor CreA and is absent insorA3mutant conidia, which exhibit resistance tol-sorbose toxicity. An intermediate-affinity system (Km∼400 μM) is present insorA3conidia germinating in derepressing conditions.creAderepressed mutants show enhanced sensitivity tol-sorbose. The high-affinity uptake system ap…
Pathophysiological Aspects of Glucose Uptake by the Tumor Tissue under Various Conditions of Oxygen and Glucose Supply
1976
Earlier examinations of the glucose uptake in neoplastic tissue by isolated DS- Carcinosarcoma implanted into the rat kidney had the results as follows (VAUPEL, 1974): 1. An increase of the tumor mass from 3 to 13 g wet weight caused an exponential decrease of the glucose consumption by the tumor tissue from 44.4 to 6.7/umoles per 100 g/min; very young tumors of 3 – 4 g bad uptake rates from 27.8 to 44.4/umoles/100 g/min. 2. Simultaneous measurements of the mean actual glucose concentrations in the tumor tissue showed that in the very young tumors the concentration still ranged from 1.75 to 2.25/umoles/g wet weight, whereas those in old tumors drop as low as 0 to 0.17/umoles/g.
Splenic respiratory gas exchange and glucose uptake in patients with splenomegaly in hypersplenism and Hodgkin's disease.
1977
Blood samples are taken from the splenic artery, vein and pulp of patients suffering from Hodgkin's disease (n=10) or hypersplenism (n=7) and undergoing splenectomy. In these samples, the relevant parameters of the respiratory gas exchange as well as glucose and lactate concentrations are determined. In hypersplenism (mean splenic wet weight: 543 g) the mean oxygen consumption of the splenic tissue amounts to 0.9 ml O2/100 g/min taking into account a mean splenic blood flow of 80 ml/100 g/min. The glucose uptake and the lactate release are 9 mg/100 g/min and 5.5 mg/100 g/min, respectively. These values are in close agreement with the results obtained in the normal and undisturbed spleen in …
Diabetes Secondary to Acromegaly: Physiopathology, Clinical Features and Effects of Treatment.
2018
Acromegaly is a rare disease due to chronic GH excess and to the consequent increase in IGF-1 levels. Both GH and IGF-1 play a role in intermediate metabolism affecting glucose homeostasis. Indeed, chronic GH excess impairs insulin sensitivity, increases gluconeogenesis, reduces the glucose uptake in adipose tissue and muscle and alters pancreatic β cells function. As a consequence, glucose metabolism alterations are a very frequent complication in acromegaly patients, further contributing to the increased cardiovascular risk and mortality. Treatment modalities of acromegaly differently impact on glucose tolerance. Successful surgical treatment of acromegaly ameliorates glucose metabolism a…
Hypertension, diabetes mellitus, and insulin resistance: the role of intracellular magnesium.
1997
Magnesium is one of the most abundant ions present in living cells and its plasma concentration is remarkably constant in healthy subjects. Plasma and intracellular magnesium concentrations are tightly regulated by several factors. Among them, insulin seems to be one of the most important. In fact, in vitro and in vivo studies have demonstrated that insulin may modulate the shift of magnesium from extracellular to intracellular space. Intracellular magnesium concentration has also been shown to be effective on modulating insulin action (mainly oxidative glucose metabolism), offset calcium-related excitation-contraction coupling, and decrease smooth cell responsiveness to depolarizing stimul…
Early, but not late onset estrogen replacement therapy prevents oxidative stress and metabolic alterations caused by ovariectomy.
2014
Aims: The usefulness of estrogen replacement therapy (ERT) in preventing oxidative stress associated with menopause is controversial. We aimed to study if there is a critical time window for effective treatment of the effects of ovariectomy with estrogens at the molecular, metabolic, and cellular level. Results: Our main finding is that early, but not late onset of ERT prevents an ovariectomy-associated increase in mitochondrial hydrogen peroxide levels, oxidative damage to lipids and proteins, and a decrease in glutathione peroxidase and catalase activity in rats. This may be due to a change in the estrogen receptor (ER) expression profile: ovariectomy increases the ER α/β ratio and immedi…
Addition of NMDA-receptor antagonist MK801 during oxygen/glucose deprivation moderately attenuates the upregulation of glucose uptake after subsequen…
2011
During stroke the blood–brain barrier (BBB) is damaged which can result in vasogenic brain edema and inflammation. The reduced blood supply leads to decreased delivery of oxygen and glucose to affected areas of the brain. Oxygen and glucose deprivation (OGD) can cause upregulation of glucose uptake of brain endothelial cells. In this letter, we investigated the influence of MK801, a non-competitive inhibitor of the NMDA-receptor, on the regulation of the glucose uptake and of the main glucose transporters glut1 and sglt1 in murine BBB cell line cerebEND during OGD. mRNA expression of glut1 was upregulated 68.7- fold after 6 h OGD, which was significantly reduced by 10 μM MK801 to 28.9-fold.…
Effects of repeated treatments with an extract ofGinkgo biloba (EGb 761) and bilobalide on liver and muscle glycogen contents in the non-insulin-depe…
1997
The effects of repeated (15-day) oral treatments with an extract of Ginkgo biloba (EGb 761; 50 mg/kg/day) or with its terpenoid constituent, bilobalide (2 mg/kg/day), were assessed in normal rats and in rats that had been previously injected with streptozotocin (50 mg/kg, i.p. in saline solution), a dose which provided a model of non-insulin-dependent diabetes mellitus (NIDDM). In this model of diabetes, blood glucose is significantly increased while the circulating insulin level remains unchanged. Glucose penetrates cells because of decreased glycogen turnover, a metabolic abnormality that can be revealed by using an oral glucose tolerance test (OGTT). In control rats, hyperglycemia was ac…
Effects of repeated treatments with an extract ofGinkgo biloba (EGb 761) and bilobalide on glucose uptake and glycogen synthesis in rat erythrocytes:…
1994
The metabolic action of an extract of Ginkgo biloba (EGb 761) has been examined in an ex vivo study of rat erythrocytes. Oral administration of EGb 761 (100 mg/kg/day) for 5 days to Wistar rats caused an increase in the in vitro uptake of glucose by erythrocytes, especially in high-glucose (13.32 mM) medium, an effect that was associated with an increase in intracellular energy metabolism and reflected as a significant reduction in free glucose concentration. In contrast, the lactate concentration of the erythrocytes and lactate release to the bathing medium were not modified. Conversion of glucose into glycogen was significantly increased in the erythrocytes of EGb 761-treated animals. Tak…