Vitamins in rat

O Brien, M. L., Twaroski, T. R, Cunningham, M. L., Glauert, H. R, and Spear, B. T. (2001b). Effects of peroxisome proliferators on antioxidant enzymes and antioxidant vitamins in rats and hamsters. 

Little is known of the mechanism of breakdown of vitamin A in humans or in other animals. Some insight into vitamin A catabolism was achieved by injecting " C-labeled vitamin in rats. Some water-soluble " C-compounds were excreted, demonstrating that part of the vitamin must be catabolized. Five per cent of the vitamin-labeled carbon was expired in the form ofC02. 

It has been known for some years that vitamin K must be reduced to its hydroquinone for activity in prothrombin synthesis, i.e. it is the hydroquinone that is the active metabolite of the vitamin. In rats treated with warfarin and given C-... 

Bioassays are based on the growth response of vitamin-depleted rats or chicks to graded amounts of vitamin B 2 added in the diet. These assays are not specific for vitamin B 2 because factors, other than vitamin B 2 present in biological materials, produce a growth response. Because coen2yme primary form of natural vitamin 2 is light sensitive, assays should be carried out in subdued light. 

USP also issues vitamin D capsules for AO AC deterrnination in rats and an oil solution for the vitamin D AO AC deterrnination in chicks. Historically, the following units (shown with their approximate international unit equivalence) have been used but are currendy abandoned 1 clinical unit = 12-17 lU 1 biological unit = 0.125 lU 1 protection unit = 0.125 lU 1 Laquer unit = 0.14 lU 1 Poulson unit = 0.2 lU 1 Steenbach unit = 3 lU. The MRC, ICU, and Coward units all approximated the international unit and are also no longer in common use. 

Brewers and bakers dried yeasts are used as dietary supplements. They contribute some protein and trace minerals, and some B vitamins, but no vitamin C, vitamin B 2 or fat-soluble vitamins. The glucose tolerance factor (GTE) of yeast, chromium nicotinate, mediates the effect of insulin. It seems to be important for older persons who caimot synthesize GTE from inorganic dietary chromium. The ceU wall fraction of bakers yeast reduces cholesterol levels in rats fed a hypercholesteremic diet. 

In a study of the effect of nutrition on reproduction in the rat in the 1920s, Herbert Evans and Katherine Bishop found that rats failed to reproduce on a diet of rancid lard, unless lettuce or whole wheat was added to the diet. The essential factor was traced to a vitamin in the wheat germ oil. Named vitamin E by Evans (using the next available letter following on the discovery of vita-... 

We demonstrated that the mutagenic activity from the reaction of nitrite and Sanma was carcinogenic (48). It is quite relevant that this product induced glandular stomach cancer in rats. Since the formation of the mutagen can be blocked by vitamin C, it would seem that the formation of glandular stomach cancer can also be so Inhibited. 

The two major sites of P-carotene conversion are the intestine and liver in hnmans. The liver seems to have a greater capacity for metabolizing P-carotene to vitamin A than the intestine. " In rats, BCO activity was also reported to be higher in the small intestine and liver, followed by brain, Inng, and kidney. In agreement with the tissne distribntion of BCO activity, high levels of hnman BCO mRNA were reported in the jejnnnm, liver, and kidney, whereas lower levels were present in the prostate, testes, ovaries, and skeletal mnscles. 

Perumal, A.S., Gopal, V.B., Tordzro, W.K., Cooper, T.B. and Cadet, J.L. (1992). Vitamin E attenuates the toxic effects of 6-hydrooxydopamine on free radical scavenging systems in rat brain. Brain Res. Bull. 29, 699-701. 

Lead was found to decrease tissue levels of vitamin C in a study in rats (Vij et al. 1998). Since vitamin C is required for the synthesis of heme, the authors suggested that some hematological effects of lead (e.g., inhibition of ALAD) may be due at least partially to a lead-induced decrease in bioavailability or increased demand of vitamin C. Supplementation with vitamin C almost completely restored ALAD activity in blood and liver. 

Parvin, S. G. and B. Sivakumar. 2000. Nutritional status affects intestinal carotene cleavage activity and carotene conversion to vitamin A in rats. J Nutr 130(3) 573-577. 

Salgo and Pryor [111] studied the effect of Trolox C (a water-soluble analog of vitamin E) on peroxynitrite-mediated DNA damage in rat thymocytes. They proposed that peroxynitrite mediated the formation of TBAR products, which caused the DNA-protein crosslinks. The latter were inhibited by the posttreatment of cells with Trolox. However, Trolox produced no effects on hydrogen peroxide- or bleomycin-induced DNA damage in human lymphocytes [108],... 

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