ESTIMATION OF THE BIOLOGICAL POTENCY OF VARIOUS FORMS OF VITAMIN A

1961 ◽  
Vol 39 (11) ◽  
pp. 1687-1693 ◽  
Author(s):  
T. K. Murray ◽  
J. A. Campbell
Keyword(s):  
Vitamin A ◽  
Antimony Trichloride ◽  
Vaginal Smear ◽  
Biological Potency ◽  
Liver Storage

The low biological potency of 9-cis and 9,13-di-cis vitamin A, heretofore measured by growth and liver storage assays, has been confirmed by vaginal smear assays. Appreciable quantities of these isomers in pharmaceuticals would lead to overestimation of biological potency by the U.S.P. XV or the antimony trichloride methods. In an extensive series of assays the U.S.P. method accurately estimated the biological potency of most oil-soluble, water-dispersed, and dry, stabilized samples of vitamin A. The antimony trichloride method did not accurately estimate biological potency but, for many samples, correction of these values in accordance with their maleic values was not justified. Water-dispersed and dry, stabilized samples of vitamin A were not better utilized than oil solutions of the vitamin.

scholarly journals The Biological Potency of Vitamin A in Whale Liver Oil and its Molecular Distillates

1950 ◽  
Vol 16 (2) ◽  
pp. 46-52 ◽  
Author(s):  
K. SABASI ◽  
A. NAKAYAMA ◽  
S. HIRAO ◽  
T. KINUMAKI
Keyword(s):  
Vitamin A ◽  
Biological Potency

Relationship of Vitamin A Blood Level in the Rat to Vitamin A Intake and to Liver Storage

1941 ◽  
Vol 46 (2) ◽  
pp. 248-250 ◽  
Author(s):  
J. M. Lewis ◽  
O. Bodansky ◽  
K. G. Falk ◽  
G. McGuire
Keyword(s):  
Vitamin A ◽  
Blood Level ◽  
Relationship Of ◽  
Liver Storage

Comparison of Vitamin a Liver Storage Following Administration of Vitamin a in Oily and Aqueous Media

1948 ◽  
Vol 35 (2) ◽  
pp. 225-238 ◽  
Author(s):  
Albert E. Sobel ◽  
Marvin Sherman ◽  
Jacqueline Lichtblau ◽  
Selig Snow ◽  
Benjamin Kramer
Keyword(s):  
Vitamin A ◽  
Aqueous Media ◽  
Liver Storage

ISOMERIZATION OF 11-cis VITAMIN A IN VIVO

1960 ◽  
Vol 38 (11) ◽  
pp. 1219-1222 ◽  
Author(s):  
D. W. Stainer ◽  
T. K. Murray ◽  
J. A. Campbell
Keyword(s):  
Vitamin A ◽  
Intestinal Tract ◽  
Biological Potency ◽  
Oral Doses ◽  
Poor Absorption ◽  
Cis Isomer

Single oral doses of all-trans and 11-cis vitamin A acetate were given to young, vitamin A deficient rats and the proportion of cis isomer in the intestinal tract and liver measured. Some conversion of 11-cis to all-trans occurred in the stomach and intestine, and a mixture of the two isomers was absorbed and stored in the liver. The high proportion of cis isomer found in the liver stores 5 hours after a dose of 11-cis vitamin A disappeared completely in 23 days. Oral doses of both all-trans and 11-cis vitamin A produced greater liver stores than the same doses given subcutaneously. The relative biological potency of the 11-cis isomer was the same by either route, which indicated that the low potency of this isomer was not due only to poor absorption from the intestine.

The effect of different plant sources on the utilization of carotene by chickens

1957 ◽  
Vol 49 (1) ◽  
pp. 113-119 ◽  
Author(s):  
I. Ascarelli ◽  
A. Bondi
Keyword(s):  
Vitamin A ◽  
Sweet Potato ◽  
Normal Growth ◽  
Carotene Content ◽  
Green Plants ◽  
Forage Plants ◽  
Feed Control ◽  
Different Sources ◽  
Sweet Potato Leaves ◽  
Liver Storage

The possibility was examined of supplying vitamin A to chickens from the first days of life as carotene in green plants. Growth experiments were carried out with chickens till the age of 8 weeks. Different kinds of forage (horse-beans, Berseem clover, green oats, sweet potato leaves, cow-peas, corn-leaves) were given in quantities calculated to supply 300 μg. carotene per 100 g. feed; control groups received fish-liver oil, given at the level of 500 i.u. per 100 g. feed. Weight gains and extent of vitamin A storage in liver served as an indication of the utilization of carotene from different sources. The utilization of carotene from all the plants examined was sufficient to support normal growth, only in the groups receiving clover was growth found to be somewhat slower. Remarkable differences were found in the extent of liver storage, and that was taken as an indication of differences in activity of the carotene from the different sources.Attempts to determine the reasons for these differences in liver storage capacity of the carotene from the various plants did not reveal the presence of any plant components enhancing or depressing vitamin A storage.Similarly, no correlation could be found between digestibility coefficients of carotene in the different plants and liver vitamin A storage. This correlation seemed likely in sweet potato leaves only, the rather low digestibility coefficient found in these leaves may account, at least partially, for the low activity of this plant.The stereoisomeric composition of the β-carotene of the different plants and the xanthophyll/carotene ratio are very similar in all plants tested and cannot account for differences in carotene activity of the plants studied.The results of this work show that it is possible to satisfy the requirements of chicks for vitamin A from the first days of life by supplying certain forage plants. In practice, because of the variability of the carotene content in such plants, care has to be taken when estimating the amounts to be given. Green plants should be given to chickens freely or at least in liberal amounts.

STUDIES ON ANTIOXIDANT ACTIVITY: I. ESTIMATION OF ANTIOXIDANT ACTIVITY IN STABILIZING VITAMIN A IN OILS

1941 ◽  
Vol 19b (1) ◽  
pp. 17-23 ◽  
Author(s):  
W. E. Parker ◽  
A. C. Neish ◽  
W. D. McFarlane
Keyword(s):  
Antioxidant Activity ◽  
Vitamin A ◽  
Wheat Germ ◽  
Chloroform Solution ◽  
Ultra Violet ◽  
Antimony Trichloride ◽  
Direct Application ◽  
Wheat Germ Oil ◽  
Destructive Action ◽  
Antioxidant Potency

The efficiency of wheat-germ oil in stabilizing vitamin A against the destructive action of ultra-violet radiations was investigated. A rapid and convenient method of estimating antioxidant potency is described which is based on ultraviolet irradiation of mixtures of halibut liver oil and antioxidant in chloroform solution and estimation of vitamin A by the direct application of the antimony trichloride reaction employing photoelectric colorimetry.

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.

A STUDY OF THE SUCCESSION OF VISUAL PIGMENTS IN PACIFIC SALMON (ONCORHYNCHUS)

1966 ◽  
Vol 44 (3) ◽  
pp. 429-455 ◽  
Author(s):  
D. D. Beatty
Keyword(s):  
Vitamin A ◽  
Sockeye Salmon ◽  
Pacific Salmon ◽  
Progressive Increase ◽  
Visual Pigments ◽  
Antimony Trichloride ◽  
The Other ◽  
Simple Function ◽  
Partial Bleaching ◽  
Colorimetric Reaction

Retinae of Pacific salmon (Oncorhynchus) have mixtures of two visual pigments, one a retinene1 (VP 5031) and the other a retinene2 pigment (VP 5272). Retinal extracts were prepared from individuals of five species collected at different times of the year. These extracts were subjected to partial bleaching experiments to determine the proportions of the two visual pigments. Liver extracts were prepared and the percentages of vitamin A1 and vitamin A2 were estimated in these extracts by means of the Carr-Price (antimony trichloride) colorimetric reaction. There was a progressive increase in the percentage of VP 5272 in retinae of adult coho, king, pink, chum, and sockeye salmon during the spawning migration. Except for the sockeye salmon, this increase resulted in a conversion from a retina having predominantly VP 5031 to one having a preponderance of VP 5272- Juvenile coho and king salmon exhibited changes in the proportions of the two visual pigments during the year, but similar changes did not occur in juvenile sockeye salmon. The percentage of VP 5272 in the retina is not a simple function of the proportion of vitamin A2 in the liver; however, there was an increase in the percentage of vitamin A2 in the liver of adult salmon which accompanied the increase in the proportion of VP 5272.

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