نتایج جستجو برای: ascorbate levels
تعداد نتایج: 923535 فیلتر نتایج به سال:
Previous studies showed that administration of ascorbate to glutathione (GSH)-deficient newborn rats and guinea pigs prevented toxicity and mortality and led to increased tissue and mitochondrial GSH levels; ascorbate thus spares GSH. In the present work, we tried to answer the converse question: Does administration of GSH spare ascorbate? Because administered GSH is not well transported into m...
The intermediate lobe of the pituitary contains the alpha-amidated peptide alpha-melanotropin and high levels of a copper and ascorbate-dependent peptidylglycine alpha-amidating monooxygenase (PAM) capable of converting peptides terminating in -X-Gly into amidated products (-X-NH2). As reported previously, the ability of cultured intermediate pituitary cells to produce alpha-amidated alpha-mela...
During hibernation in Arctic ground squirrels (Spermophilus parryii), O(2) consumption and plasma leukocyte counts decrease by >90%, whereas plasma concentrations of the antioxidant ascorbate increase fourfold. During rewarming, O(2) consumption increases profoundly and plasma ascorbate and leukocyte counts return to normal. Here we investigated the dynamic interrelationships among these change...
Oxidative stress and free radical production have been implicated in Alzheimer's disease, where low levels of the antioxidant vitamin C (ascorbate) have been shown to be associated with the disease. In this study, neuroblastoma SH-SY5Y cells were treated with hydrogen peroxide in the presence of ascorbate in order to elucidate the mechanism(s) of protection against oxidative stress afforded by ...
Ascorbate is a strong antioxidant; however, it can also act as a prooxidant in vitro by reducing transition metals. To investigate the in vivo relevance of this prooxidant activity, we performed a study using guinea pigs fed high or low ascorbate doses with or without prior loading with iron dextran. Iron-loaded animals gained less weight and exhibited increased plasma beta-N-acetyl-D-glucosami...
Glutathione deficiency, induced in adult mice by administering buthionine sulfoximine (an inhibitor of glutathione synthesis), led to a rapid and substantial increase in ascorbate in the liver. This effect was apparent 2-4 hr after giving the inhibitor; subsequently, the level of ascorbate decreased and that of dehydroascorbate increased markedly, supporting the conclusion that glutathione func...
Sufficient uptake and whole body distribution of vitamin C (ascorbate) is essential for many biochemical processes, including some that are vital for tumor growth and spread. Uptake of ascorbate into cancer cells is modulated by availability, tumor blood flow, tissue diffusion parameters, and ascorbate transport proteins. Uptake into cells is mediated by two families of transport proteins, name...
Hypoxia-inducible factor-1 (HIF-1) is a heterodimer transcription factor whose elevated activity in many cancers helps them to survive under hypoxic conditions and enhances their capacity to grow invasively, establish metastases, and survive chemo- or radiotherapy. Optimal intracellular levels of ascorbate suppress the level and transcriptional activity of HIF-1under normoxic or mildly hypoxic ...
Two wheat cultivars, C306 and PBW343 contrasting in drought tolerance were compared for their antioxidant response and Lea genes' expression under salt stress (SS) and combined stress (CS) of salt stress plus water stress during seedlings growth. The drought susceptible cultivar (PBW343) behaved different towards SS/CS than towards WS. It accumulated more dry masses in shoots, more ascorbate, h...
Ascorbate, or vitamin C, is usually thought of as an antioxidant. The body tightly controls blood levels of orally ingested ascorbate, capping them at 0.2 mM. However, Qi Chen et al. show that injection can circumvent this limit, allowing pharmacological concentrations up to 30 mM, which exert an oxidative effect and slow tumor growth. A previous study suggested that ascorbate might be effectiv...
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