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Effect of exogenous ascorbic acid intake on biosynthesis of ascorbic acid in mice
Life Sciences
|January 1, 1989
Summary
High dietary ascorbic acid (vitamin C) intake in mice lowered the activity of enzymes responsible for its own synthesis. This suggests vitamin C levels regulate its production through a local feedback mechanism.
Area of Science:
- Biochemistry
- Nutritional Science
- Animal Physiology
Background:
- Ascorbic acid (vitamin C) is an essential nutrient.
- The endogenous synthesis of ascorbic acid is regulated by various factors.
Purpose of the Study:
- To investigate the impact of exogenous ascorbic acid intake on the biosynthesis of ascorbic acid in mice.
- To explore the regulatory mechanisms controlling ascorbic acid synthesis.
Main Methods:
- Mice were fed diets supplemented with 0.5%, 1%, or 5% ascorbic acid for two months.
- Activity of ascorbic acid synthesizing enzymes in liver homogenates was measured using L-gulono-gamma-lactone as a substrate.
Main Results:
- Increased dietary ascorbic acid led to higher blood ascorbic acid concentrations.
- Enzyme activities involved in ascorbic acid synthesis in the liver decreased with higher ascorbic acid intake.
- Erythorbic acid, an ascorbic acid stereoisomer, did not affect enzyme activities.
Conclusions:
- Ascorbic acid synthesis in mice appears to be regulated by a local feedback mechanism.
- Hepatic portal blood ascorbic acid concentration may play a role in regulating endogenous synthesis.