scholarly journals Effect of pharmacological doses of ascorbic acid on the hepatic microsomal haemoproteins in the guinea-pig

1983 ◽  
Vol 49 (1) ◽  
pp. 27-33 ◽  
Author(s):  
Judith L. Sutton ◽  
T. K. Basu ◽  
J. W. T. Dickerson
Keyword(s):  
Ascorbic Acid ◽  
Guinea Pig ◽  
Guinea Pigs ◽  
Sucrose Solution ◽  
Significant Rise ◽  
Mixed Function Oxidase ◽  
Ascorbic Acid Deficiency ◽  
Acid Deficiency ◽  
Specific Activities ◽  
Endogenous Substrates

1. Ascorbic acid deficiency results in a reduction in the activity of the hepatic mixed function oxidase systems in the guinea-pig. In this study, male Dunkin-Hartley guinea-pigs were given 0, 50, 100, 200 or 300 mg ascorbic acid/d in two equal doses in buffered sucrose solution (200 g/l) for 4 d. Controls received an equal volume of sucrose solution.2. A dose of 50 mg ascorbic acid/d resulted in a significant rise in the specific activities of both cytochromes P-450 and b5. At doses of 200 and 300 mg ascorbic acid/d the concentration of both haemoproteins was significantly lower than the control values. These effects were mirrored by total microsomal haem concentration.3. These results suggest that when given in large doses, ascorbic acid ceases to act simply as a vitamin and should be considered a drug competing for substrates and cofactors with co-administered drugs and endogenous substrates such as cholesterol.

Effect of Prolonged Marginal Ascorbic Acid Deficiency on Lenticular Levels of Antioxidants and Lipid Peroxide in Guinea Pigs

2001 ◽  
Vol 71 (2) ◽  
pp. 103-109 ◽  
Author(s):  
Yoshiji Ohta ◽  
Takafumi Niwa ◽  
Takashi Yamasaki
Keyword(s):  
Ascorbic Acid ◽  
Vitamin E ◽  
Guinea Pigs ◽  
Antioxidant Status ◽  
Serum Vitamin ◽  
Lipid Peroxide ◽  
Ascorbic Acid Content ◽  
Ascorbic Acid Deficiency ◽  
Acid Deficiency ◽  
Deficient Group

We examined the effect of prolonged marginal ascorbic acid deficiency of the levels of antioxidants and lipid peroxide in lenses of guinea pigs in order to clarify lenticular antioxidant status under ascorbic acid deficiency. Male guinea pigs aged 4 weeks were given a scorbutic diet (20 g/animal per day) with either marginally deficient ascorbic acid (0.5 mg/animal per day) or sufficient ascorbic acid (1 g/animal per day) in drinking water for 3 and 6 months. The deficient group showed no lens opacity during the administration period. The deficient group had 62.3 and 53.9% of lenticular ascorbic acid content in the sufficient group at 3 and 6 months of ascorbic acid deficiency, respectively. There were no differences in lenticular contents of reduced glutathione and thiobarbituric acid reactive substances, an index of lipid peroxidation, between both groups at 3 and 6 months of ascorbic acid deficiency, while the deficient group tended to have higher lenticular vitamin E content than the sufficient group. The deficient group had higher serum vitamin E concentration than the sufficient group at 3 and 6 months of ascorbic acid deficiency. These results indicate that lenticular antioxidant status is maintained well in guinea pigs with prolonged marginal ascorbic acid deficiency, which may result in no cataract formation.

scholarly journals The effect of siderosis and ascorbic acid depletion on bone metabolism, with special reference to osteoporosis in the Bantu

1971 ◽  
Vol 25 (3) ◽  
pp. 367-376 ◽  
Author(s):  
A. A. Wapnick ◽  
S. R. Lynch ◽  
H. C. Seftel ◽  
R. W. Charlton ◽  
T. H. Bothwell ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Bone Resorption ◽  
Bone Formation ◽  
Iron Overload ◽  
Bone Mineral ◽  
Guinea Pigs ◽  
Iron Concentration ◽  
Ascorbic Acid Deficiency ◽  
Acid Deficiency ◽  
Liver Storage

1. There is an association between iron overload, ascorbic acid deficiency and osteoporosis in middle-aged South African Bantu males. The iron overload contributes to the ascorbic acid deficiency by accelerating its oxidative catabolism. The object of the present investigation was to explore the possibility that the osteoporosis results from chronic ascorbic acid deficiency.2. On quantitative microradiography, percentage bone-formation surface was normal but percentage bone-resorption surface was significantly increased in ten osteoporotic subjects compared with seven control subjects.3. There was a significant inverse correlation between bone mineral density and liver storage iron concentration in thirty-five Bantu subjects. In thirteen individuals aged 39 years or less, liver storage iron concentration was significantly correlated with percentage bone-resorption surface.4. Guinea-pigs deprived of ascorbic acid for 21 d exhibited both significantly diminished percentage bone-formation surface and increased percentage bone-resorption surface.5. Guinea-pigs overloaded with iron by injections of iron dextran developed significantly reduced hepatic ascorbic acid concentrations and bone mineral densities; percentage bone-formation surface was significantly diminished and percentage bone-resorption surface significantly increased. Ascorbic acid injection largely prevented the bone changes.

scholarly journals Ascorbic acid deficiency affects the metabolism of cytosolic ferritin but not lipid-associated ferritin in livers of guinea pigs

1990 ◽  
Vol 267 (2) ◽  
pp. 535-537 ◽  
Author(s):  
B E Cham ◽  
H P Roeser ◽  
A C Nikles
Keyword(s):  
Ascorbic Acid ◽  
Acid Concentration ◽  
Iron Content ◽  
Guinea Pigs ◽  
Physicochemical Characteristics ◽  
Ascorbic Acid Concentration ◽  
Ascorbic Acid Deficiency ◽  
Functional Roles ◽  
Acid Deficiency ◽  
Synthesis And Degradation

Two physicochemically and metabolically separate pools of ferritin, namely cytosolic ferritin and lipid-associated ferritin, are present in the livers of guinea pigs. In this paper we establish that the iron content of cytosolic ferritin is dependent on and linearly related to ascorbic acid concentration, whereas changes in concentration of this vitamin do not affect the iron content of lipid-associated ferritin. In livers of ascorbic acid-deficient guinea pigs both synthesis and degradation of cytosolic ferritin are diminished equally. Consequently cytosolic ferritin is metabolized more slowly without changes in its pool size. In contrast with cytosolic ferritin, the metabolism of lipid-associated ferritin is unaffected by ascorbic acid deficiency. The differential effects of ascorbic acid deficiency on the physicochemical characteristics as well as on the metabolism of cytosolic ferritin and lipid-associated ferritin suggest that the two forms of ferritin have different functional roles.

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