scholarly journals Effects of dietary vitamin A intake on acrosin- and plasminogen-activator activity of ram spermatozoa

Reproduction ◽  
2005 ◽  
Vol 129 (6) ◽  
pp. 707-715 ◽  
Author(s):  
I A Zervos ◽  
M P Tsantarliotou ◽  
G Vatzias ◽  
P Goulas ◽  
N A Kokolis ◽  
...  
Keyword(s):  
Vitamin A ◽  
Plasminogen Activator ◽  
Proteolytic Enzymes ◽  
Vitamin A Deficiency ◽  
Plasminogen Activators ◽  
The Body ◽  
Dietary Vitamin ◽  
Retinyl Acetate ◽  
Plasminogen Activator Activity ◽  
Group B

Acrosin and plasminogen activators are proteolytic enzymes of ram spermatozoa that play an essential role in the induction of the acrosome reaction, as well as the binding of spermatozoa to the oocyte and their penetration through the layers that surround the oocyte. Since vitamin A can alter gene expression in various tissues, testis included, this study was undertaken to evaluate the possible effect of vitamin A intake on acrosin- and plasminogen-activator activity. During a 20-week experiment, 15 rams of the Greek breed Karagouniki, divided to three groups, received different amounts of vitamin Aper osin retinyl acetate capsules (group A, controls, 12 500 iu/animal per day; group B, 50 000 iu/animal per day; group C, 0 iu/animal per day up to the 13th week, then 150 000 iu/animal per day until the end of the experiment). Acrosin- and plasminogen-activator activity were determined by spectrophotometric methods. Vitamin A was determined in blood plasma by HPLC. No statistical differences were detected regarding the body weight of the rams or the qualitative and quantitative parameters of their ejaculate throughout the whole experiment. No statistically significant alterations of enzyme activity were detected in group B. In group C, both enzyme activities started declining in week 9. Compared with controls, maximum reduction for acrosin was 49% on week 11 and for plasminogen activators 51% in week 14. Activities returned to normal rates after vitamin A resupplementation. To date, the main result of vitamin A deficiency was known to be arrest of spermatogenesis and testicular degeneration. A new role for vitamin A may be suggested, since it can influence factors related to male reproductive ability before spermatogenesis is affected.

Research Recommendations for Applying Vitamin A-Labelled Isotope Dilution Techniques to Improve Human Vitamin A Nutrition

2014 ◽  
Vol 84 (Supplement 1) ◽  
pp. 52-59 ◽  
Author(s):  
Sherry A. Tanumihardjo ◽  
Anura V. Kurpad ◽  
Janet R. Hunt
Keyword(s):  
Public Health ◽  
Vitamin A ◽  
Vitamin A Deficiency ◽  
Human Subjects ◽  
The Body ◽  
Pool Size ◽  
Serum Retinol ◽  
Vitamin A Status ◽  
Status Assessment ◽  
Total Body

The current use of serum retinol concentrations as a measurement of subclinical vitamin A deficiency is unsatisfactory for many reasons. The best technique available for vitamin A status assessment in humans is the measurement of total body pool size. Pool size is measured by the administration of retinol labelled with stable isotopes of carbon or hydrogen that are safe for human subjects, with subsequent measurement of the dilution of the labelled retinol within the body pool. However, the isotope techniques are time-consuming, technically challenging, and relatively expensive. There is also a need to assess different types of tracers and doses, and to establish clear guidelines for the use and interpretation of this method in different populations. Field-friendly improvements are desirable to encourage the application of this technique in developing countries where the need is greatest for monitoring the risk of vitamin A deficiency, the effectiveness of public health interventions, and the potential of hypervitaminosis due to combined supplement and fortification programs. These techniques should be applied to validate other less technical methods of assessing vitamin A deficiency. Another area of public health relevance for this technique is to understand the bioconversion of β-carotene to vitamin A, and its relation to existing vitamin A status, for future dietary diversification programs.

Vitamin A deficiency among children younger than 5 y in India: an analysis of national data sets to reflect on the need for vitamin A supplementation

2020 ◽  
Author(s):  
G Bhanuprakash Reddy ◽  
Raghu Pullakhandam ◽  
Santu Ghosh ◽  
Naveen K Boiroju ◽  
Shalini Tattari ◽  
...  
Keyword(s):  
Vitamin A ◽  
Vitamin A Deficiency ◽  
Public Health Problem ◽  
Sample Survey ◽  
Dietary Vitamin ◽  
High Dose ◽  
Serum Retinol ◽  
Indian Children ◽  
Vitamin A Supplementation ◽  
National Prevalence

ABSTRACT Background Biochemical vitamin A deficiency (VAD) is believed to be a serious public health problem (low serum retinol prevalence >20%) in Indian children, justifying universal high-dose vitamin A supplementation (VAS). Objective To evaluate in Indian children younger than 5 y the risk of biochemical VAD from the Comprehensive National Nutrition Survey, as well as dietary vitamin A inadequacy and excess over the tolerable upper limit of intake (TUL) from national and subnational surveys, factoring in fortification and VAS. Methods Child serum retinol data, corrected for inflammation, were examined to evaluate national- and state-level prevalence of VAD. Simultaneously, dietary intakes from the National Sample Survey Office and the National Nutrition Monitoring Bureau were examined for risk of dietary vitamin A deficiency against its average requirement (AR) derived for Indian children. Theoretical estimates of risk reduction with oil and milk vitamin A fortification were evaluated along with the risk of exceeding the TUL, as well as when combined with intake from VAS. Results The national prevalence of biochemical VAD measured in 9563 children was 15.7% (95% CI: 15.2%, 16.3%), and only 3 states had prevalence significantly >20%. The AR of vitamin A was 198 and 191 µg/d for boys and girls; the risk of dietary inadequacy was ∼70%, which reduced to 25% with oil and milk fortification. Then, the risk of exceeding the TUL was 2% and 1% in 1- to 3-y-old and 4- to 5-y-old children, respectively, but when the VAS dose was added to this intake in a cumulative 6-mo framework, the risk of exceeding the TUL rose to 30% and 8%, respectively. Conclusion The national prevalence of VAD risk is below 20% in Indian children. Because there is risk of excess intake with food fortification and VAS, serious consideration should be given to a targeted approach in place of the universal VAS program in India.

scholarly journals Bilateral Keratomalacia Secondary to Diet Induced Vitamin A Deficiency in an Ethiopian Young woman: A Case Report

1970 ◽  
Vol 29 (2) ◽  
Author(s):  
Kumale Tolesa Daba ◽  
Dagmawit Kifle ◽  
Jafer Kedir Ababora
Keyword(s):  
Vitamin A ◽  
Low Socioeconomic Status ◽  
Night Blindness ◽  
Early Recognition ◽  
Vitamin A Deficiency ◽  
The Body ◽  
Parotid Glands ◽  
Low Socioeconomic ◽  
Background Diet ◽  
University Department

BACKGROUND: Diet induced vitamin A deficiency is less commonly seen in otherwise healthy adults, due to large store of vitamin A in the body. Night blindness is the commonest manifestation of vitamin A deficiency in adults, whereas Keratomalacia is a rare manifestation.CASE REPORT: A 27 years old Ethiopian woman came to Jimma University Department of Ohthalmology with a compliant of protrusion of the globe content of both eyes within a week, after having redness and fear of light of both eyes for 2 months. She was a mother of twins and had low socioeconomic status. On general examination, she was cachectic with enlarged parotid glands. On ocular examination, she was bilaterally blind and had dry ocularsurface. There was bilaterally melted cornea with prolapsed uveal tissue. After several investigations she was diagnosed as bilateral Keratomalacia (stage X3B) secondary to diet induced vitamin A deficiency. She was supplemented with vitamin A and other nutritional supplementation. Topical lubricating drops and ointments were administered. Finally, conjunctival flap was done to preserve the globe.CONCLUSION: Although it is rare, treating physicians should be aware of the occurrence of Keratomalacia in adults which is potentially blinding. Early recognition and treatment of vitamin A deficiency at the stage of night blindness is essential in reducing blindness caused by Keratomalacia.

scholarly journals Improving the Dietary Vitamin A Content of Rural Communities in South Africa by Replacing Non-Biofortified White Maize and Sweet Potato with Biofortified Maize and Sweet Potato in Traditional Dishes

Nutrients ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1198 ◽  
Author(s):  
Laurencia Govender ◽  
Kirthee Pillay ◽  
Muthulisi Siwela ◽  
Albert Thembinkosi Modi ◽  
Tafadzwanashe Mabhaudhi
Keyword(s):  
South Africa ◽  
Rural Communities ◽  
Vitamin A ◽  
Sweet Potato ◽  
Vitamin A Deficiency ◽  
Nutritional Composition ◽  
Dietary Vitamin ◽  
Micronutrient Deficiencies ◽  
Isoleucine Leucine ◽  
Lower Protein

Biofortification of staple crops has a potential for addressing micronutrient deficiencies, such as vitamin A deficiency (VAD), which are prevalent in South Africa. The poor acceptability of provitamin A (PVA)-biofortified foods could be improved by combining them with other food items to produce modified traditional dishes. The nutritional composition of the dishes could also be improved by the modification. The study aimed to investigate the effect of replacing white maize and cream-fleshed sweet potato (CFSP)] with PVA-biofortified maize and orange-fleshed sweet potato (OFSP) on the nutritional composition of South African traditional dishes. The protein, fibre, total mineral (ash), lysine, and iron concentrations of the PVA maize phutu (traditional porridge) composite dishes (control), were not significantly different (P > 0.05) from those of white maize phutu composite dishes. However, the PVA concentration of PVA maize phutu composite dishes was higher than that of the white phutu composite dishes (P > 0.05). The OFSP had a significantly lower protein concentration, but a significantly higher (P > 0.05) fibre, ash, lysine, isoleucine, leucine, and PVA concentration, relative to the CFSP. The findings indicate that composite dishes in which white maize is replaced with PVA-biofortified maize, and switching over from CFSP to OFSP, would contribute to combating VAD in South Africa, and in other developing counties.

scholarly journals Vitamin A-Deficient Diet Accelerated Atherogenesis in Apolipoprotein E−/−Mice and Dietaryβ-Carotene Prevents This Consequence

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Noa Zolberg Relevy ◽  
Dror Harats ◽  
Ayelet Harari ◽  
Ami Ben-Amotz ◽  
Rafael Bitzur ◽  
...  
Keyword(s):  
Vitamin A ◽  
Apolipoprotein E ◽  
Vitamin A Deficiency ◽  
Plasma Cholesterol ◽  
Atherosclerotic Lesion ◽  
Dietary Vitamin ◽  
Control Group ◽  
Chow Diet ◽  
Deficient Diet ◽  
Aortic Sinus

Vitamin A is involved in regulation of glucose concentrations, lipid metabolism, and inflammation, which are major risk factors for atherogenesis. However, the effect of vitamin A deficiency on atherogenesis has not been investigated. Therefore, the objective of the current study was to examine whether vitamin A deficiency accelerates atherogenesis in apolipoprotein E-deficient mice (apoE−/−). ApoE−/−mice were allocated into the following groups: control, fed vitamin A-containing chow diet; BC, fed chow diet fortified withDunaliellapowder containingβc isomers; VAD, fed vitamin A-deficient diet; and VAD-BC group, fed vitamin A-deficient diet fortified with aDunaliellapowder. Following 15 weeks of treatment, liver retinol concentration had decreased significantly in the VAD group to about 30% that of control group. Vitamin A-deficient diet significantly increased both plasma cholesterol concentrations and the atherosclerotic lesion area at the aortic sinus (+61%) compared to the control group. Dietaryβc fortification inhibited the elevation in plasma cholesterol and retarded atherogenesis in mice fed the vitamin A-deficient diet. The results imply that dietary vitamin A deficiency should be examined as a risk factor for atherosclerosis and that dietaryβc, as a sole source of retinoids, can compensate for vitamin A deficiency.

scholarly journals Evaluation of a two-generation rat model for vitamin A deficiency and the interrelationship with iron metabolism

1995 ◽  
Vol 74 (5) ◽  
pp. 689-700 ◽  
Author(s):  
Annet J. C. Roodenburg ◽  
Clive E. West ◽  
Robert Hovenier ◽  
Anton C. Beynen
Keyword(s):  
Vitamin A ◽  
Rat Model ◽  
Binding Capacity ◽  
Vitamin A Deficiency ◽  
Dietary Vitamin ◽  
Vitamin A Status ◽  
Normal Vitamin ◽  
Before And After ◽  
Pregnancy And Lactation ◽  
Plasma Retinol

In order to induce a range of vitamin A-deficient states in young growing rats and to study the effect of vitamin A deficiency on Fe status, we designed the following two-generation experiment. Dams were fed on diets with one of five vitamin A levels from 2 weeks before and throughout pregnancy and lactation. The pups received the same diets as their mothers both before and after weaning. The five dietary levels of vitamin A were 1200, 450, 150, 75 and 0 retinol equivalents/kg feed. Vitamin A intake did not affect reproduction outcome, nor were body and liver weights of the pups affected when they were 3·5 weeks old. Male pups with normal vitamin A status had higher plasma retinol levels than female pups. Vitamin A status of the offspring was affected from 3·5 weeks onwards. Body and liver weights were decreased in the male pups given the lowest dietary vitamin A levels from week 6·5 onwards but not in the female pups. Fe status was marginally affected. Haemoglobin levels were increased and total Fe-binding capacity was decreased in the groups given no dietary vitamin A at week 9·5. Splenic Fe was increased only in the male pups given the lowest levels of dietary vitamin A. However, as a whole, Fe status was only mildly affected and subject to considerable variation. We conclude that the two-generation rat model described here is not suitable for studying effects of vitamin A deficiency on Fe metabolism.

scholarly journals Multiple cytochrome P-450 genes are concomitantly regulated by vitamin A under steady-state conditions and by retinoic acid during hepatic first-pass metabolism

2011 ◽  
Vol 43 (1) ◽  
pp. 57-67 ◽  
Author(s):  
A. Catharine Ross ◽  
Christopher J. Cifelli ◽  
Reza Zolfaghari ◽  
Nan-qian Li
Keyword(s):  
Gene Expression ◽  
Retinoic Acid ◽  
Steady State ◽  
Vitamin A ◽  
Dynamic Range ◽  
Dynamic Change ◽  
The Body ◽  
Retinol Binding Protein ◽  
Dietary Vitamin ◽  
Wide Range

Vitamin A (retinol) is an essential precursor for the production of retinoic acid (RA), which in turn is a major regulator of gene expression, affecting cell differentiation throughout the body. Understanding how vitamin A nutritional status, as well as therapeutic retinoid treatment, regulates the expression of retinoid homeostatic genes is important for improvement of dietary recommendations and therapeutic strategies using retinoids. This study investigated genes central to processes of retinoid uptake and storage, release to plasma, and oxidation in the liver of rats under steady-state conditions after different exposures to dietary vitamin A (deficient, marginal, adequate, and supplemented) and acutely after administration of a therapeutic dose of all- trans-RA. Over a very wide range of dietary vitamin A, lecithin:retinol acyltransferase (LRAT) as well as multiple cytochrome P-450s (CYP26A1, CYP26B1, and CYP2C22) differed by diet and were highly correlated with one another and with vitamin A status assessed by liver retinol concentration (all correlations, P < 0.05). After acute treatment with RA, the same genes were rapidly and concomitantly induced, preceding retinoic acid receptor (RAR)β, a classical direct target of RA. CYP26A1 mRNA exhibited the greatest dynamic range (change of log 26 in 3 h). Moreover, CYP26A1 increased more rapidly in the liver of RA-primed rats than naive rats, evidenced by increased CYP26A1 gene expression and increased conversion of [3H]RA to polar metabolites. By in situ hybridization, CYP26A1 mRNA was strongly regulated within hepatocytes, closely resembling retinol-binding protein (RBP)4 in location. Overall, whether RA is produced endogenously from retinol or administered exogenously, changes in retinoid homeostatic gene expression simultaneously favor both retinol esterification and RA oxidation, with CYP26A1 exhibiting the greatest dynamic change.

scholarly journals Preparation, properties and metabolism of retro-3-dehydroretinyl acetate

1968 ◽  
Vol 109 (2) ◽  
pp. 293-299 ◽  
Author(s):  
A. Krishna Mallia ◽  
M. R. Lakshmanan ◽  
K. V. John ◽  
H. R. Cama
Keyword(s):  
Small Intestine ◽  
Vitamin A ◽  
Hydrobromic Acid ◽  
The Body ◽  
Rat Intestine ◽  
Retinyl Acetate ◽  
Major Site ◽  
Rat Growth ◽  
Growth Assay ◽  
Biological Potency

1. Treatment of 3-dehydroretinyl acetate with aqueous hydrobromic acid resulted in the formation of retro-3-dehydroretinyl acetate, which, on alkaline hydrolysis, gave the corresponding alcohol. 2. retro-3-Dehydroretinyl acetate was isomerized to 3-dehydrovitamin A when fed to vitamin A-deficient rats. 3. When retro-3-dehydroretinyl acetate was administered orally, it was hydrolysed to retro-3-dehydroretinol in the rat intestine, isomerized to 3-dehydroretinol and esterified before being transported to the liver for storage. 4. When administered intraperitoneally, both 3-dehydrovitamin A and retro-3-dehydrovitamin A were accumulated in liver and other tissues, whereas after enterectomy 3-dehydrovitamin A was not detected anywhere in the body. 5. The small intestine was shown to be the major site of conversion of retro-3-dehydrovitamin A into 3-dehydrovitamin A. 6. The extent of conversion of retro-3-dehydroretinyl acetate into 3-dehydrovitamin A was much smaller than that of the conversion of retro-retinyl acetate into vitamin A. 7. The biological potency of retro-3-dehydroretinyl acetate, determined by the rat-growth assay, was 2·6% of that all-trans-retinyl acetate, when given orally.

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