Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0003969 (vitamin C deficiency)
 625 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

2 studies, A and B, were conducted to determine the metabolic effects of oral contraceptives (OCs). The subjects were healthy nonsmokers (17 to 27 years old, 1.52 m. to 1.75 m. in height, and 50 kg. to 60 kg. in weight) who were not undergoing any therapy. Controls did not have any previous history of hormonal therapy. In Study A, biochemical data from 17 women who were not on OCs were compared with those of women taking pills containing either 30 ug of ethinyl estradiol (EE) and 150 ug of D. norgestrel (18 women) or 50 ug. of EE and 250 ug. of D. norgestrel (9 women). In Study B, 8 women were studied before and during 3 to 4 cycles of low-dosed OC therapy (30 ug. of EE and 150 ug. of D. norgestrel). In both studies, the 2 oral contraceptive dosage forms had similar metabolic quantitative and qualitative changes: both resulted in an increase in serum concentration of triglycerides (30 to 33%), B-lipoproteins (27 to 29%), and ceruloplasmin (75 to 90%), and a decrease in serum levels of antithrombin 3 (22 to 29%) and ascorbic acid (30 to 42%). Serum cholesterol and phospholipid concentration did not change. The proportion of serum cholesterol carried by a-lipoproteins (high density lipoproteins) did decrease (the change is much smaller than that seen in coronary heart disease) while that carried by B-lipoproteins (or low density and very low density lipoproteins) increased. A significant negative correlation was observed between serum concentrations of ascorbic acid and cholesterol; this is interesting as clinical and experimental evidence suggests that latent ascorbic acid deficiency leads to hypercholesteroleamia, while ascorbic acid supplements reduce plasma cholesterol levels. As 500 mg. daily of ascorbic acid supplements supposedly help maintain normal ascorbic acid levels in blood during OC use, they should perhaps be prescribed to pill users in this study.
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PMID:Metabolic effects of oral contraceptives containing 30 micrograms and 50 micrograms of oestrogen. 23 Apr 11

Copper uptake from human ceruloplasmin (Cp) into cells of a human erythroleukemic cell line, K562, was investigated. The interaction between ascorbic acid and the copper atoms in ceruloplasmin was a focal point of the study. Nondenatured 67Cu-labeled ceruloplasmin (67Cu-Cp) was prepared by an ascorbate-catalyzed exchange of Cp with 67CuCl2 in vitro. The complex was stable, even in the presence of 1.0 mM ascorbate. Adding K562 cells and incubating at 37 degrees C resulted in an immediate transfer of 67Cu from ceruloplasmin to the cells. At 37 degrees C the copper accumulated by the K562 cells resisted dissociation by mild acid washing. The rate of transfer of 67Cu was proportional to the Cp concentration in the medium. Ascorbate (100 microM) enhanced the uptake of 67Cu at least fourfold. D-Isoascorbate worked as well as L-ascorbate, suggesting that the reducing potential of the vitamin (or its isomer) was important in the uptake of copper. Approximately 20% of the 67Cu absorbed into the cytosol was precipitable with antibodies to Cu-Zn superoxide dismutase (Cu-Zn SOD). Ascorbate, however, did not enhance the incorporation of radioactivity into Cu-Zn SOD, suggesting that copper may not be the only rate-limiting factor in the synthesis of this enzyme in K562 cells. The possible relevance of these observations to vitamin C deficiency is discussed.
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PMID:Ascorbate enhances copper transport from ceruloplasmin into human K562 cells. 272 26

Female, adult guinea pigs were fed a low ascorbic acid diet ad libitum. Oral administrations of either estinyl (5 micrograms) or progestogen (250 micrograms) in combination with 5 mg of ascorbic acid (minimum requirement) daily for 21 d, resulted in significantly lower (P less than 0.05) concentrations of ascorbic acid in plasma, liver, adrenals and urine than in animals receiving only 5 mg of the vitamin. None of these animals showed any clinical signs of ascorbic acid deficiency. Clinical manifestations of scurvy were exhibited, however, when animals receiving no ascorbic acid supplement were treated with the steroid hormones for 7 d. All of these animals died by d 10. On the other hand, the animals receiving neither ascorbic acid nor the steroids remained free from any signs of scurvy, except one (out of six), which died by d 12. In vitro studies revealed a markedly higher rate of oxidation of ascorbic acid in the presence of either estinyl or progestogen than in untreated controls. These results were further supported by a higher level of plasma ceruloplasmin in animals receiving a combination of estrogen and progestogen than in animals receiving no hormones. An in vivo dose-related effect of ascorbic acid indicated that the steroid-mediated lowering effect of the vitamin status could be counteracted by increasing the dose of ascorbic acid from 5 to 10 mg/d for 2 wk. These results suggest that the interactions between oral contraceptive hormones and ascorbic acid may be of clinical importance only in the case of borderline intake of the vitamin.
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PMID:Effects of estrogen and progestogen on the ascorbic acid status of female guinea pigs. 395 5

Although interaction of vitamin C, copper and iron have been studied in several species, little is known about these interactions in species which require the vitamin in the diet. Young male Hartley guinea pigs were fed a basal diet, or a basal diet and supplemented daily with vitamin C, p.o. Pharmacologic doses (25 mg per 100 g BW per day) of vitamin C resulted in two-to-three-fold decreases in liver copper, when compared with those receiving normal (0.5 mg per 100 g BW per day) intakes. Under conditions of vitamin C deficiency, serum copper and ceruloplasmin were elevated along with liver copper. Serum and hepatic iron levels, hepatic microsomal cytochrome P-450 and cytochrome b5, and blood heme parameters all appeared to be directly related to vitamin C intake, i.e. the iron and heme parameters increased as the vitamin dose increased. These data are consistent with the hypothesis that interaction between vitamin C, copper and iron influence normal heme formation through the oxidation/reduction of iron and/or by regulating iron absorption and availability at the gut level.
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PMID:Effect of vitamin C on copper and iron metabolism in the guinea pig. 742 59