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.

scholarly journals Preparation, properties and metabolism of 5,6-monoepoxy-3-dehydroetinal

1969 ◽  
Vol 111 (1) ◽  
pp. 23-26 ◽  
Author(s):  
A. Krishna Mallia ◽  
M. R. Lakshmanan ◽  
K. V. John ◽  
H. R. Cama
Keyword(s):  
Vitamin A ◽  
Rat Growth ◽  
Growth Assay ◽  
Biological Potency ◽  
Reduction And Oxidation

1. 5,6-Monoepoxy-3-dehydroretinal was synthesized from 3-dehydroretinyl acetate and characterized. 2. When fed to vitamin A-deficient rats, 5,6-monoepoxy-3-dehydroretinal was converted into 5,6-monoepoxy-3-dehydrovitamin A and stored in the liver. 3. It was demonstrated that the rat possesses the necessary enzymes for the reduction and oxidation of 5,6-monoepoxy-3-dehydroretinal to the corresponding alcohol and acid respectively. 4. The biological potency of the epoxy-3-dehydroretinal by the rat-growth assay (determined by USP XIV procedure) was 1·07% of that of vitamin A.

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.

KINETICS OF URIC ACID TRANSPORT AND ITS PRODUCTION IN RAT SMALL INTESTINE

1967 ◽  
Vol 45 (1) ◽  
pp. 121-127 ◽  
Author(s):  
Jung H. Oh ◽  
John B. Dossetor ◽  
Ivan T. Beck
Keyword(s):  
Uric Acid ◽  
Small Intestine ◽  
Intestinal Wall ◽  
The Body ◽  
Rat Small Intestine ◽  
Acid Transport ◽  
Major Site ◽  
Initial Concentration ◽  
Uricosuric Agents ◽  
Kinetics Of

Segments of the middle third of rat small intestine were incubated at 30 °C for 1 hour in the model of Crane and Wilson. When comparison was made between the uric acid contained in unincubated segments and that in both incubated segments and their incubation media, the latter was found to exceed the former nearly fivefold. This indicates that the small intestine is a major site of uric acid production in the body. The rate of uric acid-14C transport across the intestinal wall was studied with the same model, and found to be linearly proportional to its initial concentration gradient in both directions. This rate was not altered by hypoxanthine or uricosuric agents, which have been shown to influence uric acid transport in other systems. It is concluded, therefore, that uric acid transport across the wall of the small intestine is by passive diffusion.

Structure and function of the gut

2010 ◽  
pp. 2201-2204
Author(s):  
D.G. Thompson
Keyword(s):  
Small Intestine ◽  
Gastrointestinal Tract ◽  
Oral Cavity ◽  
Anal Sphincter ◽  
Structure And Function ◽  
The Body ◽  
Major Site ◽  
Colon And Rectum ◽  
Small Intestinal ◽  
And Function

The gastrointestinal tract is a hollow tube stretching from the oral cavity through the oesophagus, stomach, small intestine, colon, and rectum to the anal sphincter. Its function is the transport, digestion, and elimination of ingested material to supply nutrients, vitamins, minerals, and electrolytes that are essential for life, together with the protection of the rest of the body from injurious or allergenic material. The stomach acts as a storage, sterilizing, and digestive tank; the small intestine is the major site of digestion and absorption; the colon’s function is to salvage water and electrolyte from the small intestinal effluent; and the rectum provides a storage function, enabling the elimination of colonic residue (defecation) to be restricted to times of personal convenience....

Structure and function of the gastrointestinal tract

2020 ◽  
pp. 2721-2726
Author(s):  
Michael E.B. FitzPatrick ◽  
Satish Keshav
Keyword(s):  
Small Intestine ◽  
Gastrointestinal Tract ◽  
Oral Cavity ◽  
Anal Sphincter ◽  
Structure And Function ◽  
The Body ◽  
Major Site ◽  
Colon And Rectum ◽  
Small Intestinal ◽  
And Function

The gastrointestinal tract is a hollow tube stretching from the oral cavity through the oesophagus, stomach, small intestine, colon, and rectum to the anal sphincter. Its function is the transport, digestion, and elimination of ingested material to supply nutrients, vitamins, minerals, and electrolytes that are essential for life, together with the protection of the rest of the body from injurious or allergenic material. The stomach acts as a storage, sterilizing, and digestive tank; the small intestine is the major site of digestion and absorption; the colon’s function is to salvage water and electrolytes from the small intestinal effluent; and the rectum provides a storage function, enabling the elimination of colonic residue (defecation) to be restricted to times of personal convenience.

scholarly journals α-Retinol and 3,4-didehydroretinol support growth in rats when fed at equimolar amounts and α-retinol is not toxic after repeated administration of large doses

2013 ◽  
Vol 111 (8) ◽  
pp. 1373-1381 ◽  
Author(s):  
Napaporn Riabroy ◽  
Joseph T. Dever ◽  
Sherry A. Tanumihardjo
Keyword(s):  
Vitamin A ◽  
Liver Toxicity ◽  
Repeated Administration ◽  
Negative Control ◽  
Retinol Binding Protein ◽  
Retinyl Acetate ◽  
Deficient Diet ◽  
Treatment Groups ◽  
Body Weights ◽  
Growth Assay

Dietary α-carotene is present in oranges and purple-orange carrots. Upon the central cleavage of α-carotene in the intestine, α-retinal and retinal are formed and reduced to α-retinol (αR) and retinol. Previous reports have suggested that αR has 2 % biopotency of all-trans-retinyl acetate due in part to its inability to bind to the retinol-binding protein. In the present work, we carried out three studies. Study 1 re-determined αR's biopotency compared with retinol and 3,4-didehydroretinol in a growth assay. Weanling rats (n 40) were fed a vitamin A-deficient diet for 8 weeks, divided into four treatment groups (n 10/group) and orally dosed with 50 nmol/d retinyl acetate (14·3 μg retinol), α-retinyl acetate (143 μg αR), 3,4-didehydroretinyl acetate (14·2 μg DR) or cottonseed oil (negative control). Supplementation was continued until the control rats exhibited deficiency signs 5 weeks after the start of supplementation. Body weights and AUC values for growth response revealed that αR and DR had 40–50 and 120–130 % bioactivity, respectively, compared with retinol. In study 2, the influence of αR on liver ROH storage was investigated. The rats (n 40) received 70 nmol retinyl acetate and 0, 17·5, 35 or 70 nmol α-retinyl acetate daily for 3 weeks. Although liver retinol concentrations differed among the groups, αR did not appreciably interfere with retinol storage. In study 3, the accumulation and disappearance of αR over time and potential liver pathology were determined. The rats (n 15) were fed 3·5 μmol/d α-retinyl acetate for 21 d and the groups were killed at 1-, 2- and 3-week intervals. No liver toxicity was observed. In conclusion, αR and didehydroretinol are more biopotent than previously reported at sustained equimolar dosing of 50 nmol/d, which is an amount of retinol known to keep rats in vitamin A balance.

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.

Influence of zeolite and shungite on the content of vitamin A in the body of broiler chickens for mycotoxicosis

2020 ◽  
Vol 23 (12) ◽  
pp. 51-54
Author(s):  
S.A. Tanaseva ◽  
◽  
О.K. Ermolaeva ◽  
L.E. Matrosova ◽  
A.Z. Mukharlyamov ◽  
...  
Keyword(s):  
Vitamin A ◽  
Broiler Chickens ◽  
The Body

Review of Curd, Paneer and Cheese as Nitya Asevaniya Ahara Dravya w.s.r. to Dadhi, Kilat and Kurchika

2017 ◽  
Vol 2 (1) ◽  
Author(s):  
Saylee Deshmukh ◽  
Vyas M. K.
Keyword(s):  
Vitamin A ◽  
Growth And Development ◽  
Milk Protein ◽  
The Body ◽  
Rich Source ◽  
Food Items ◽  
Common Food ◽  
Daily Diet ◽  
Healthy Growth

Curd, Paneer and Cheese are rich source of milk protein, calcium, Vitamin A, Phosphorous, vitamins, minerals and protein which are required by the body in high proportions for healthy growth and development. It is common food in India. Cheese is also a rich source of fat. Curd, Paneer and Cheese can be correlated with Dadhi, Paneer and Cheese in Ayurveda classics which are listed in Nitya Asevaniya Ahara Dravya (food items not to be taken in daily diet). Present study aims to explain rationale behind description of these food items as Nitya Asevaniya Ahara Dravya.

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