Effects of retinoic acid on the concentrations of radioactive metabolites of retinol in tissues of rats maintained on a retinol-deficient diet

1991 ◽  
Vol 69 (6) ◽  
pp. 826-830 ◽  
Author(s):  
Pangala V. Bhat ◽  
André Lacroix

The effect of feeding retinoic acid for 2 and 6 days on the metabolism of labeled retinol in tissues of rats maintained on a vitamin A deficient diet was studied. The metabolites of retinol were analyzed by high performance liquid chromatography. Feeding retinoic acid for 2 days significantly reduced the blood retinol and retinyl ester levels without affecting the vitamin A content of the liver. In intestine and testis the content of labeled retinoic acid was decreased significantly by dietary retinoic acid. Addition of retinoic acid to the diet for 6 days resulted, in addition to decreased blood retinol and retinyl ester values, in an increase in the retinyl ester values in the liver. The accumulation of retinyl ester in the retinoic acid fed rat liver was accompanied by an absence of labeled retinoic acid. Kidney tissue was found to contain the highest levels of labeled retinoic acid, retinol, and retinyl esters; dietary retinoic acid did not alter the concentrations of these retinoids in the kidney during the experimental period. Since kidney retained more vitamin A when the liver vitamin A was low and also dietary retinoic acid did not affect the concentrations of radioactive retinoic acid in the kidney, it is suggested that the kidney may play a major role in the production of retinoic acid from retinol in the body.Key words: retinol, retinoic acid, vitamin A deficiency, tissue metabolites, rat.

1969 ◽  
Vol 23 (3) ◽  
pp. 619-626 ◽  
Author(s):  
W.A. Coward ◽  
J.McC. Howell ◽  
J.N. Thompson ◽  
G. A. J. PITT

1. Hooded rats were fed from weaning on a basal retinol-deficient diet containing retinoic acid. Such a diet maintains growth and general health but does not prevent the appearance of lesions associated with vitamin A deficiency in the retina and testis. Some animals were also given supplements of retinol averaging 0.1, 0.25, 1 or 5 μg retinyl acetate per day. Rats were killed at intervals up to 28 weeks after weaning. The weights of the testes and the histological appearance of the testes and epididymides indicated that 5 μg retinyl acetate per day had maintained spermatogenesis throughout the experimental period. Doses averaging 1 μg retinyl acetate per day were only partially effective and the two smaller doses had little beneficial effect.2. In a second similar experiment rats were given doses of retinyl acetate averaging 0.25, 0.5, 1, 2 or 100 μg per day. Measurements of the electroretinogram thresholds of the rats indicated that a dose of 1 μg retinyl acetate per day maintained mainly normal vision until the end of the experiment 29 weeks after weaning. Additional histological observations made 21 weeks after weaning showed that this dose level had not maintained spermatogenesis but that doses of 2 μg retinyl acetate per day had been effective.3. The experiments show that the differing functions of vitamin A in spermatogenesis and vision are reflected in the hooded rat in differences in the dietary retinol levels needed to maintain these processes.


2013 ◽  
Vol 83 (2) ◽  
pp. 122-128 ◽  
Author(s):  
Cécile Renaud ◽  
Jacques Berger ◽  
Arnaud Laillou ◽  
Sylvie Avallone

Vitamin A deficiency is still one of the major public health problems in least developed countries. Fortification of vegetable oils is a strategy implemented worldwide to prevent this deficiency. For a fortification program to be effective, regular monitoring is necessary to control food quality in the producing units. The reference methods for vitamin A quantification are expensive and time-consuming. A rapid method should be useful for regular assessment of vitamin A in the oil industry. A portable device was compared to high-performance liquid chromatography (HPLC) for three plant oils (rapeseed, groundnut, and soya). The device presented a good linearity from 3 to 30 mg retinol equivalents per kg (mg RE.kg- 1). Its limits of detection and quantification were 3 mg RE.kg- 1 for groundnut and rapeseed oils and 4 mg RE.kg- 1 for soya oil. The intra-assay precision ranged from 1.48 % to 3.98 %, considered satisfactory. Accuracy estimated by the root mean squares error ranged from 3.99 to 5.49 and revealed a lower precision than HPLC (0.4 to 2.25). Although it offers less precision than HPLC, the device estimates quickly the vitamin A content of the tested oils from 3 or 4 to 15 mg RE.kg- 1.


2011 ◽  
Vol 81 (5) ◽  
pp. 335-342 ◽  
Author(s):  
Fabian Rohner ◽  
Simone K. Frey ◽  
Ralf Mothes ◽  
Andrea Hurtienne ◽  
Simone Hartong ◽  
...  

Vitamin A deficiency continues to be a global public health problem. Fortification of oil with vitamin A is considered a cost-effective, feasible strategy to prevent this problem but quality control poses a challenge to program implementation. To overcome this, we have validated a newly developed device that quantitatively measures the content of retinyl palmitate in refined palm oil, is simple to use, and yields immediate results.Linearity of analysis ranged from 2.5 - 30 mg retinol equivalents (RE)/ kg of palm oil, with 2.5 mg RE/kg being the determination limit; inter- and intra-assay precision ranged from 1.4 - 7.1 %. Comparison with a high-performance liquid chromatography method showed high agreement between the methods (R2 = 0.92; Limits of Agreement: -1.24 mg to 2.53 mg RE/kg), and further comparisons illustrate that the new device is useful in low-resource settings. This device offers a field- and user-friendly solution to quantifying the vitamin A content in refined palm oil.


2020 ◽  
Vol 7 (1) ◽  
pp. 24-31
Author(s):  
Samia Sams ◽  
Mohammad Khairul Alam ◽  
Monira Ahsan ◽  
Sheikh Nazrul Islam

Background: Carotenoids are natural plant pigments and precursors of vitamin A, which provide a health benefit, protect against chronic degenerative diseases, and contribute to immune functions. Utilization and identification of foods with a high content of carotenoids received greater attention nowadays. Objective: The present study was aimed at evaluating total carotenoids content (TCC) and carotene composition of unconventional leafy vegetables growing in Bangladesh. Materials and Methods: The samples were collected from different locations of Bangladesh and mixed together to ensure sample representativeness. Acetone–petroleum ether extraction followed by spectrophotometric measurement was utilized for quantification of TCC. High-performance liquid chromatography (HPLC- DAD) was used to separate and quantify carotene components. Results and Discussion: The TCC values ranged from 129.38 μg/100 g edible portion (EP) in Helencha to 12803.31 μg/100 g EP in Roktodrone. The study findings also revealed that the selected plant samples exhibited high content of β-carotene ranging from 120.99 μg/100 g EP in Parul to 11301.16 μg/100 g EP in Roktodrone. It was also observed that most of the vegetables analyzed did not have α-carotene, lycopene, β-cryptoxanthin or it was in such a small quantity that could not be detected with HPLC. Conclusion: It can be suggested that regular intake of these vegetables may provide pro-vitamin A. In order to address the vitamin A deficiency and to maintain biodiversity, the analysis of carotenoids composition of these unconventional plant foods is to be initiated and make it available to the mass population. It would also fill up the data gap in the existing food composition table of Bangladesh.


2003 ◽  
Vol 90 (1) ◽  
pp. 191-198 ◽  
Author(s):  
Marianne Husson ◽  
Valérie Enderlin ◽  
Serge Alfos ◽  
Catherine Féart ◽  
Paul Higueret ◽  
...  

Recent studies have revealed that retinoids play an important role in the adult central nervous system and cognitive functions. Previous investigations in mice have shown that vitamin A deficiency (VAD) generates a hypo-expression of retinoic acid (RA, the active metabolite of vitamin A) receptors and of neurogranin (RC3, a neuronal protein involved in synaptic plasticity) and a concomitant selective behavioural impairment. Knowing that RC3 is both a triiodothyronine (T3) and a RA target gene, and in consideration of the relationships between the signalling pathways of retinoids and thyroid hormones, the involvement of T3 on RA signalling functionality in VAD was investigated. Thus, the effects of vitamin A depletion and subsequent administration with RA and/or T3 on the expression of RA nuclear receptors (RAR, RXR), T3 nuclear receptor (TR) and on RC3 in the brain were examined. Rats fed a vitamin A-deficient diet for 10 weeks exhibited a decreased expression of RAR, RXR and TR mRNA and of RC3 mRNA and proteins. RA administration to these vitamin A-deficient rats reversed only the RA hypo-signalling in the brain. Interestingly, T3 is able to restore its own brain signalling simultaneously with that of vitamin A and the hypo-expression of RC3. These results obtained in vivo revealed that one of the consequences of VAD is a dysfunction in the thyroid signalling pathway in the brain. This seems of crucial importance since the down regulation of RC3 observed in the depleted rats was corrected only by T3.


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