Survey of animal livers for vitamin A content

Scotter, Michael J.; Thorpe, S. A.; Reynolds, S. L.; Wilson, Lee A; Lewis, D. John

doi:10.1080/02652039209374067

Cited by 14 publications

(5 citation statements)

References 2 publications

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“…Results of the present study show that total amounts of vitamin A in uterine tissue were comparable to those found in other extrahepatic tissues but much lower than those found in the liver, where levels are generally below 400 g/g, ranging between 10 and 1100 g/g tissue [14]. With the progress of gestation, both the quantitative measurement by HPLC and the semiquantitative method of macroscopic and microscopic fluorescence showed a decrease in total vitamin A.…”

Section: Discussionmentioning

confidence: 56%

Distribution of Vitamin A, Retinol-Binding Protein, Cellular Retinoic Acid-Binding Protein I, and Retinoid X Receptor β in the Porcine Uterus During Early Gestation1

Schweigert

Bonitz

Siegling

et al. 1999

Biology of Reproduction

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Retinol and retinol-binding protein (RBP), among the major secretory products of the uterine endometrium in the uterine fluid of pigs, are assumed to be of importance for early embryonic development. While uterine RBP has been widely characterized, little information is available on the metabolism of vitamin A itself or other specific binding proteins or nuclear receptors in the uterus of pigs. In the present study, the content and distribution of vitamin A in uterine tissue of pigs during early gestation (Days 14-30) were examined macroscopically and microscopically via autofluorescence and HPLC. In addition, the distribution of specific proteins involved in vitamin A metabolism at the cellular and nuclear level was investigated. Macroscopically, the yellowish-greenish autofluorescence characteristic of vitamin A was observed in uterine endometrium. Microscopy showed that the autofluorescence was associated with glandular and surface epithelium of the endometrium. In these structures, immunoreactive RBP was localized, as was cellular retinoic acid-binding protein I. Retinoid X receptor beta was observed in the nucleus of myometrium and endometrium. The intensity of fluorescence decreased with the progress of gestation. This decrease was paralleled by a decrease in vitamin A content of endometrium and myometrium. In general, vitamin A concentration in the endometrium was higher than in the myometrium (P < 0.01). In the myometrium, if present at all, vitamin A was found almost exclusively as retinyl esters. In the endometrium, the dominant fraction was retinol, representing more than 90% of total vitamin A. These results show for the first time that the yellowish-greenish autofluorescence in the pig uterus can be attributed to vitamin A. Differences in the form of vitamin A present in endometrium and myometrium might point to differences in metabolism. In the myometrium, vitamin A might be stored, and in the endometrium, vitamin A is present primarily as retinol-the form in which it is secreted into the uterine fluid.

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Section: Discussionmentioning

confidence: 56%

Distribution of Vitamin A, Retinol-Binding Protein, Cellular Retinoic Acid-Binding Protein I, and Retinoid X Receptor β in the Porcine Uterus During Early Gestation1

Schweigert

Bonitz

Siegling

et al. 1999

Biology of Reproduction

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“…It is important to note that there have been no case reports of birth defects from vitamin A exposure due to dietary sources [79]. Intake from a dinner with 150 g of liver would represent about 100,000 to 200,000 IU of vitamin A (30-60 mg of retinol) [86], but liver is not likely to be consumed frequently.…”

Section: Case Reports Of Teratogenicity From Preformed Vitamin Amentioning

confidence: 99%

Vitamin A and Carotenoid Toxicity

Blomhoff

2001

Food Nutr Bull

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Large differences in time and dose needed to induce hypervitaminosis A have been observed. High doses of vitamin A in food and oily solutions are well tolerated, whereas emulsified preparations have higher toxicity. Chronic hypervitaminosis seems to be induced following daily doses of 300,000 to 600,000 IU of vitamin A (90-180 mg of retinol) in oily preparations for many months or years, whereas teratogenicity may be induced by daily doses as low as 40,000 IU of vitamin A (12 mg of retinol) in oil during the first trimester. For the provitamin A, β-carotene, serious adverse effects have been reported in large-scale prospective randomized trials: four years of supplementation with 20 to 30 mg β-carotene per day was associated with increased risk of lung cancer and cardiovascular disease among smokers and workers exposed to asbestos. These results strongly suggest that high doses of β-carotene should not be recommended for any group until the safety of such doses can be established.

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“…Reports by Parker et al (1982) and Ihrke and Goldshmidt (1983) indicated that some dogs with seborrheic dermatitis responded positively to intense vitamin A supplementation; however, the long-term effect of this therapy has not been fully elucidated. Another area of concern is that the beef and pork liver and offal products used in canned dog foods are increasing in vitamin A content (Scotter et al, 1992). The average vitamin A concentration in canned dog food found in Australia was 26,225 IU/1,000 kcal ME (Heanes, 1990).…”

Section: Introductionmentioning

confidence: 99%

Effect of increasing dietary vitamin A on bone density in adult dogs.

Cline

Czarnecki-Maulden

Losonsky

et al. 1997

Journal of Animal Science

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There has been an increase in vitamin A fortification of livestock feeds resulting in increased residual vitamin A in organ meats, which are often used in canned dog foods. The effect on bone density of feeding various concentrations of vitamin A in a canned dog food product was investigated. Thirty-two random-source dogs were assigned to four treatments in a randomized complete block design. The diets contained 15,000, 50,000, 116,000, or 225,000 IU vitamin A/1,000 kcal ME. Diets were fed up to 1 yr. Computed tomography was used to determine bone density of the right tibia at 0, 3, 6, 9, and 12 mo. Computed tomography is a more sensitive technique for determining bone density in vivo than conventional x-rays. There were no differences (P > .10) in tibia bone or marrow density in any of the dogs fed the various concentrations of vitamin A. There was no interaction of time x diet on bone density (P > .05) or bone marrow density (P > .05). In addition, there were no changes in serum alkaline phosphatase, calcium, or phosphorus. These results indicate that concentrations of vitamin A three times the recommended maximum safe amount (71,429 IU/1,000 kcal ME) are not detrimental to normal bone health in dogs. Therefore, these data support the hypothesis that canines are less sensitive to excess vitamin A in the diet than some other mammals.

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Survey of animal livers for vitamin A content

Cited by 14 publications

References 2 publications

Distribution of Vitamin A, Retinol-Binding Protein, Cellular Retinoic Acid-Binding Protein I, and Retinoid X Receptor β in the Porcine Uterus During Early Gestation1

Distribution of Vitamin A, Retinol-Binding Protein, Cellular Retinoic Acid-Binding Protein I, and Retinoid X Receptor β in the Porcine Uterus During Early Gestation1

Vitamin A and Carotenoid Toxicity

Effect of increasing dietary vitamin A on bone density in adult dogs.

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