scholarly journals Effects of vitamins A and D on the biosynthesis of l-ascorbic acid by rat-liver microsomes

1965 ◽  
Vol 97 (1) ◽  
pp. 247-249 ◽  
Author(s):  
NC Ghosh ◽  
I Chatterjee ◽  
GC Chatterjee
Keyword(s):  
Vitamin D ◽  
Ascorbic Acid ◽  
Vitamin A ◽  
Rat Liver ◽  
Liver Microsomes ◽  
Rat Liver Microsomes ◽  
Stock Diet ◽  
Hypervitaminosis A ◽  
Hypervitaminosis D ◽  
Liver Tissues

1. The synthesis of l-ascorbic acid from either d-glucuronolactone or l-gulonolactone by liver microsomes of rats is decreased under conditions of hypervitaminosis A; under hypervitaminosis D the synthesis from d-glucuronolactone is increased and that from l-gulonolactone is not affected. 2. The microsomal conversion of l-gulonolactone into l-ascorbic acid is impaired in liver tissues of rats made deficient with respect to either vitamin A or vitamin D when compared with the controls maintained on stock diet.

In vitro inhibitor studies of vitamin D 25-hydroxylase in rat liver microsomes

1983 ◽  
Vol 221 (1) ◽  
pp. 38-45 ◽  
Author(s):  
Bruce Kabakoff ◽  
Heinrich K. Schnoes ◽  
Hector F. De Luca
Keyword(s):  
Vitamin D ◽  
Rat Liver ◽  
Liver Microsomes ◽  
Rat Liver Microsomes

scholarly journals The mechanism of initiation of lipid peroxidation. Evidence against a requirement for an iron(II)-iron(III) complex

1989 ◽  
Vol 258 (2) ◽  
pp. 617-620 ◽  
Author(s):  
O I Aruoma ◽  
B Halliwell ◽  
M J Laughton ◽  
G J Quinlan ◽  
J M C Gutteridge
Keyword(s):  
Lipid Peroxidation ◽  
Ascorbic Acid ◽  
Rat Liver ◽  
Liver Microsomes ◽  
Rat Liver Microsomes ◽  
Brain Phospholipids ◽  
Lag Period

When Fe2+ ions are added to rat-liver microsomes, lipid peroxidation begins after a short lag period. Fe2+-dependent peroxidation in the first few minutes of the incubation can be increased by adding Fe3+, ascorbic acid or Pb2+ ions; these stimulations are not additive. By contrast, Pb2+ ions inhibit peroxidation of microsomes in the presence of Fe3+/ascorbate or Fe3+-ADP/NADPH. In liposomes made from ox-brain phospholipids, Fe2+-dependent peroxidation is stimulated slightly by Fe3+, but much more so by ascorbic acid, Al3+ or Pb2+; these stimulations are not additive. Liposomal peroxidation in the presence of Fe3+/ascorbate is inhibited by Pb2+ or Al3+. These results argue against the participation of an Fe2+-Fe3+-O2 complex, or a critical 1:1 ratio of Fe2+ to Fe3+, in the initiation of lipid peroxidation in liposomes and rat-liver microsomes.

scholarly journals Liver microsomal membrane fluidity and lipid characteristics in vitamin A-deficient rats

1987 ◽  
Vol 245 (3) ◽  
pp. 907-910 ◽  
Author(s):  
M W Hamm ◽  
V Chan ◽  
G Wolf
Keyword(s):  
Fatty Acids ◽  
Vitamin A ◽  
Membrane Fluidity ◽  
Rat Liver ◽  
Microsomal Fraction ◽  
Liver Microsomes ◽  
Membrane Lipid ◽  
Microsomal Membrane ◽  
Rat Liver Microsomes ◽  
Omega 6

Rat liver microsomes (microsomal fraction) were isolated from vitamin A-deficient and -sufficient rats and analysed for membrane lipid characteristics. Membrane fluidity was found to be significantly decreased in microsomes from the vitamin A-deficient rats, but not in liposomes prepared from lipid extracts. Microsomes from vitamin A-deficient animals showed a significant decrease in C18:2, omega 6 and an increase in C22:5, omega 6 fatty acids.

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