EFFECTS OF ASCORBIC ACID ON MICROSOMAL DRUG METABOLISM<sup>*</sup>

Zannoni, Vincent G.; Sato, Paul H.

doi:10.1111/j.1749-6632.1975.tb29272.x

Cited by 61 publications

(15 citation statements)

References 11 publications

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“…However, ASC has been previously shown to increase liver microsomal drug metabolism (e.g. NADPH-cytochrome c reductase, NADPH-cytochrome P-450 reductase; Zannoni & Sato, 1975). The chemical reduction of MISO with Fe2+ ions and MEA reported by Bahnemann et al (1978) could be reproduced here (data not shown).…”

Section: Discussionsupporting

confidence: 74%

Sulphydryls, ascorbate and oxygen as modifiers of the toxicity and metabolism of misonidazole in vitro

Taylor¹,

Rauth²

1980

Br J Cancer

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Summary.-Equimolar concentrations of cysteamine and reduced glutathione protected against the cytotoxicity of 5mm misonidazole (MISO), whereas 5mM ascorbate enhanced its toxicity to hypoxic CHO and HeLa cells in vitro. Protection (reappearance of a shoulder region) could also be seen when cysteamine was added at later incubation times. These changes in toxicity were accompanied by changes in drug metabolism, as evidenced by radiochromatograms of cell extracts obtained after treatment with 14C-labelled MISO. In contrast, radiochromatograms obtained from cells treated with toxic levels of MISO (75mm) under aerobic conditions indicated no drug metabolism. Both toxicity and drug metabolism could be immediately halted by introducing 02 during hypoxic exposures to MISO. These observations are discussed in terms of a possible model for the metabolism-mediated toxicity of MISO and the roles which sulphydryls and 02 may play.

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Section: Discussionsupporting

confidence: 74%

Sulphydryls, ascorbate and oxygen as modifiers of the toxicity and metabolism of misonidazole in vitro

Taylor¹,

Rauth²

1980

Br J Cancer

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“…This may vary in different conditions so an estimate of the rate of the metabolism and excretion of the vitamin and its metabolites will be required in both health and disease. Iatrogenic effects on vitamin C must also be examined for there is evidence that drugs and vitamin C mutually affect each others metabolism (Rivers & Devine, 1975;Zannoni & Sato, 1975).…”

Section: Future Studiesmentioning

confidence: 99%

The level of vitamin C reserves required in man: towards a solution to the controversy

Schorah

1981

Proc. Nutr. Soc.

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“…Furthermore in the presence of inhibition of cyclooxygenase, prostaglandin F2,, stimulated the release of histamine from actively sensitized guinea-pig lung while prostaglandin E2 inhibited the release (Hitchcock, 1978). Guinea-pig lung cyclo-oxygenase is a microsomal enzyme (Parkes & Eling, 1974) and guinea-pigs deficient in ascorbic acid are also deficient in microsomal protein and have reduced activity of a number of microsomal enzymes (Zannoni & Sato, 1975).…”

Section: Discussionmentioning

confidence: 99%

EFFECT OF VARIATION IN ENDOGENOUS LEVELS OF ASCORBIC ACID ON THE in vitro IMMUNOLOGICAL RELEASE OF HISTAMINE AND SLOW REACTING SUBSTANCE OF ANAPHYLAXIS FROM ACTIVELY SENSITIZED GUINEA‐PIG LUNG FRAGMENTS

Hitchcock

1980

British J Pharmacology

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The in vitro immunological release of histamine and slow reacting substance of anaphylaxis (SRS‐A) from actively sensitized guinea‐pig lung fragments was greatly reduced when the animals were maintained on an ascorbic acid‐deficient diet. Excessive dietary levels of ascorbic acid did not increase mediator release above normal levels. Restoration of ascorbic acid in the diet of scorbutic guinea‐pigs restored in vitro immunological histamine to normal levels. Variation in dietary levels of ascorbic acid had no effect on lung histamine content. The lung ascorbic acid content was proportional to the dietary intake. Approximately 60% of the total lung ascorbic acid was removed by the process of chopping and washing of the tissue. This relationship was independent of dietary intake. The results indicate that the immunological release of mediators of inflammation from guinea‐pig lung is dependent on adequate endogenous levels of ascorbic acid.

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EFFECTS OF ASCORBIC ACID ON MICROSOMAL DRUG METABOLISM^*

Cited by 61 publications

References 11 publications

Sulphydryls, ascorbate and oxygen as modifiers of the toxicity and metabolism of misonidazole in vitro

Sulphydryls, ascorbate and oxygen as modifiers of the toxicity and metabolism of misonidazole in vitro

The level of vitamin C reserves required in man: towards a solution to the controversy

EFFECT OF VARIATION IN ENDOGENOUS LEVELS OF ASCORBIC ACID ON THE in vitro IMMUNOLOGICAL RELEASE OF HISTAMINE AND SLOW REACTING SUBSTANCE OF ANAPHYLAXIS FROM ACTIVELY SENSITIZED GUINEA‐PIG LUNG FRAGMENTS

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EFFECTS OF ASCORBIC ACID ON MICROSOMAL DRUG METABOLISM*

Cited by 61 publications

References 11 publications

Sulphydryls, ascorbate and oxygen as modifiers of the toxicity and metabolism of misonidazole in vitro

Sulphydryls, ascorbate and oxygen as modifiers of the toxicity and metabolism of misonidazole in vitro

The level of vitamin C reserves required in man: towards a solution to the controversy

EFFECT OF VARIATION IN ENDOGENOUS LEVELS OF ASCORBIC ACID ON THE in vitro IMMUNOLOGICAL RELEASE OF HISTAMINE AND SLOW REACTING SUBSTANCE OF ANAPHYLAXIS FROM ACTIVELY SENSITIZED GUINEA‐PIG LUNG FRAGMENTS

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EFFECTS OF ASCORBIC ACID ON MICROSOMAL DRUG METABOLISM^*