Ascorbic acid accumulation in plated human neutrophils

Abstract

Ascorbic acid uptake was investigated in isolated, plated human neutrophils using high-performance liquid chromatography with coulometric electrochemical detection. Freshly isolated neutrophils contained 1.3 mM ascorbic acid and accumulated significantly greater amounts when physiologic concentrations of the vitamin were present in the extracellular buffer. In several different butlers uptake was dependent on the presence of cakium and magnesium. Under these conditions, ~intillation spectrometry of ~4C]ascorbic acid in conjunction with hip-~rfo~an~ liquid chromatography was suited for measuring ascorbic acid transport.

Hyperpolarized 13 C dehydroascorbate as an endogenous redox sensor for in vivo metabolic imaging

“…Vitamin C is also an effective reducing agent protecting cells from the injurious effects of reactive oxygen species (4). Pauling championed the antiviral properties of Vitamin C, and cells of the immune system including mononuclear leukocytes and neutrophils are known to accumulate large quantities of ascorbate, which may be protective against free radicals generated during the respiratory burst (5)(6)(7). In reactions with free radicals, ascorbic acid acts as a stable electron donor, converted to the radical anion semidehydroascorbate, which can be recycled back to ascorbate by a number of mechanisms, or undergo disproportionation to form ascorbate and dehydroascorbate (8).…”

“…Here we report the development of [1- 13 C] dehydroascorbate [DHA], the oxidized form of Vitamin C, as an endogenous redox sensor for in vivo imaging using hyperpolarized 13 C spectroscopy. In murine models, hyperpolarized [1-13 C] DHA was rapidly converted to [1][2][3][4][5][6][7][8][9][10][11][12][13] C] vitamin C within the liver, kidneys, and brain, as well as within tumor in a transgenic prostate cancer mouse. This result is consistent with what has been previously described for the DHA/Vitamin C redox pair, and points to a role for hyperpolarized [1][2][3][4][5][6][7][8][9][10][11][12][13] C] DHA in characterizing the concentrations of key intracellular reducing agents, including GSH.…”

The transport of vitamin C and effects of disease

“…Transport through biological (Rose, 1989;Washko et al 1989). Vitamin C can be filtered by the kidney (Basu & Schorah, 1982) and ultrafiltered from plasma suggesting that protein binding in the blood is minimal.…”

“…The presence of Na seems to decrease the Michaelis constant (Km) and, therefore, increase the affinity of the vitamin for its membrane carrier protein rather than changing the maximum velocity Vma; (Diliberto et al 1983;Padh & Aleo, 1987;Wilson & Dixon, 1989b). There is also some evidence that divalent metal ions, such as calcium, may also stimulate ascorbate transport (Padh & Aleo, 1987;Garcia & Municio, 1990;Washko et al 1990). …”

Η Επίδραση Της Έκκεντρης Προπόνησης Σε Δείκτες Μυϊκής Βλάβης Και Οξειδωτικού Στρες

“…Ο μεταφορέας του ασκορβικού οξέος είναι πιθανό ο SVCT2 που ελέγχει και τη συγκέντρωση αυτού στα ουδετερόφιλα (Washko, Rotrosen, & Levine, 1989). Τα ουδετερόφιλα με την ενεργοποίηση τους παράγουν δραστικά στοιχεία τα οποία οξειδώνουν το ασκορβικό σε διυδροασκορβικό οξύ στον εξωκυττάριο χώρο.…”