scholarly journals The retinol requirements of rats for spermatogenesis and vision

1969 ◽  
Vol 23 (3) ◽  
pp. 619-626 ◽  
Author(s):  
W.A. Coward ◽  
J.McC. Howell ◽  
J.N. Thompson ◽  
G. A. J. PITT
Keyword(s):  
Retinoic Acid ◽  
Vitamin A ◽  
Beneficial Effect ◽  
General Health ◽  
Vitamin A Deficiency ◽  
Experimental Period ◽  
Normal Vision ◽  
Retinyl Acetate ◽  
Deficient Diet ◽  
Histological Appearance

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.

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
Keyword(s):  
High Performance Liquid Chromatography ◽  
Retinoic Acid ◽  
Vitamin A ◽  
High Performance ◽  
Vitamin A Deficiency ◽  
Kidney Tissue ◽  
Experimental Period ◽  
Deficient Diet ◽  
Retinyl Ester ◽  
Effect Of Feeding

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.

scholarly journals Studies on metabolism of vitamin A. The effect of vitamin A status on the secretion rates of some steroids into the ovarianvenous blood of pregnant rats

1971 ◽  
Vol 122 (2) ◽  
pp. 235-239 ◽  
Author(s):  
J. Ganguly ◽  
G. S. Pope ◽  
S. Y. Thompson ◽  
Joyce Toothill ◽  
J. D. Edwards-Webb ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Vitamin A ◽  
Venous Blood ◽  
Retinyl Acetate ◽  
Deficient Diet ◽  
Pregnant Rats ◽  
Vitamin A Status ◽  
Previous Demonstration ◽  
Secretion Rates ◽  
Steroid Dehydrogenase

1. Rats raised on a vitamin A-deficient diet supplemented with either retinyl acetate or retinoic acid were mated and became pregnant. 2. The rates of secretion of progesterone, 20α-hydroxypregn-4-en-3-one, oestradiol-17β and oestrone into the ovarian-venous blood of rats in these two groups were measured on days 9 and 15 of pregnancy. 3. Rates of secretion of progesterone and 20α-hydroxypregn-4-en-3-one, both on days 9 and 15, were lower for the rats given retinoic acid. No such differences were found in ovarian oestrogen secretion. 4. The implications of these results are discussed in the light of the previous demonstration that the activity of ovarian 3β-hydroxy-Δ5-steroid dehydrogenase was markedly less in pregnant rats given retinoic acid.

scholarly journals Triiodothyronine administration reverses vitamin A deficiency-related hypo-expression of retinoic acid and triiodothyronine nuclear receptors and of neurogranin in rat brain

2003 ◽  
Vol 90 (1) ◽  
pp. 191-198 ◽  
Author(s):  
Marianne Husson ◽  
Valérie Enderlin ◽  
Serge Alfos ◽  
Catherine Féart ◽  
Paul Higueret ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Vitamin A ◽  
Nuclear Receptors ◽  
Target Gene ◽  
Vitamin A Deficiency ◽  
Deficient Diet ◽  
Neuronal Protein ◽  
Knowing That ◽  
The Brain

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.

scholarly journals Effect of vitamin A nutritional status on the ribonucleic acids of liver, intestinal mucosa and testes of rats

1977 ◽  
Vol 166 (3) ◽  
pp. 339-346 ◽  
Author(s):  
M Jayaram ◽  
J Ganguly
Keyword(s):  
Molecular Weight ◽  
Retinoic Acid ◽  
Vitamin A ◽  
Nutritional Status ◽  
Intestinal Mucosa ◽  
Vitamin A Deficiency ◽  
Retinyl Acetate ◽  
Ribonucleic Acids ◽  
Appreciable Increase ◽  
Acceptor Activity

1. Vitamin A deficiency led to an increase in the oligonucleotide fraction of testes and intestinal mucosa of rats at the expense of high-molecular-weight RNA and 4S RNA, but no such changes were observed in the liver. Retinyl acetate supplementation reversed these effects in both tissues, whereas retinoic acid supplementation was almost equally effective in the mucosa but virtually ineffective in the testes. The ribonuclease activities of all the tissues remained unaffected by the above treatments. 2. The effect of vitamin A deprivation on the acceptor activity of the tRNA of the testes and intestinal mucosa was more pronounced than on the liver tRNA. The testes and mucosal tRNA of the retinoic acid-supplemented rats showed significantly lower charging capacity as compared with the retinyl acetate-supplemented ones. Here also no significant effect was observed on the liver tRNA. 3. Vitamin A deficiency caused a decrease in the percentage of poly(A) in RNA of the mucosa and testes, but not in the liver RNA. The poly(A) contents of both tissues were brought to normal by retinyl acetate supplementation; treatment with retinoic acid led to an appreciable increase in poly(A) in the mucosa, but considerably less increase in poly(A) in the testes. 4. The incorporation of H332PO4 into the rRNA and tRNA of the testes was lowered by vitamin A deficiency, but no such effects was observed in the liver RNA.

scholarly journals Changes in the tissues of guinea-pigs fed on a diet free from vitamin A but containing methyl retinoate

1967 ◽  
Vol 21 (1) ◽  
pp. 37-44 ◽  
Author(s):  
J. McC. Howell ◽  
J. N. Thompson ◽  
G. A. Pitt
Keyword(s):  
Vitamin A ◽  
Salivary Glands ◽  
Guinea Pigs ◽  
Vitamin A Deficiency ◽  
In Utero ◽  
Seminal Vesicles ◽  
Retinyl Acetate ◽  
Deficient Diet ◽  
Synthetic Diet ◽  
Normal Males

1. Forty-eight guinea-pigs were fed from weaning on a semi-synthetic diet free of retinol and carotenoids. Twenty-two of these animals received a twice-weekly supplement of methyl retinoate and fifteen received a twice-weekly supplement of retinyl acetate. The remaining eleven animals were fed on the vitamin A-free diet without supplementation.2. At varying times throughout the experiment, animals died or were killed by chloroform inhalation. Testes and seminal vesicles were weighed and these tissues together with trachea, lungs, salivary glands, bladder, eyes and vagina were examined histologically.3. The eleven guinea-pigs that received the unsupplemented diet developed signs of vitamin A deficiency after being fed on the diet for 3 or 4 weeks. Many epithelia showed a metaplastic change to the stratified squamous form often with keratinization.4. The guinea-pigs given supplements of either methyl retinoate or retinyl acetate grew at a normal rate and developed none of the signs of vitamin A deficiency that appeared in the animals on the unsupplemented diet. Evidence of metaplastic change in epithelia was not seen in any of these animals.5. Thirteen males were fed on the deficient diet and methyl retinoate. The testicles and seminal vesicles of these animals weighed less than those of the ten males fed on the deficient diet and retinyl acetate. The testes of the former showed severe histological degeneration of the seminiferous epithelium. The testes of the guinea-pigs fed on retinyl acetate were normal.6. Fifteen guinea-pigs fed on the deficient diet and retinyl acetate were mated to normal males. Eleven were thought to have become pregant. Eight of these gave birth to twenty-four pups. One died in advanced pregnancy with five apparently normal pups in utero and one produced three living young and died with one still in utero. Sixteen guinea-pigs fed on the deficient diet and methyl retinoate were mated to normal males. Twelve were thought to have conceived but all resorbed their foetuses.7. The vision of guinea-pigs fed on the synthetic diet and methyl retinoate deteriorated progressively, and after 150 days on the experiment the pupils did not respond to light. However, degeneration of the retina, such as had been seen in rats fed on a vitamin A-deficient diet containing methyl retinoate, was not seen in any of the guinea-pigs.

scholarly journals The biological activity of retinoic acid in the domestic fowl and the effects of vitamin A deficiency on the chick embryo

1969 ◽  
Vol 23 (3) ◽  
pp. 471-490 ◽  
Author(s):  
J. N. Thampson ◽  
J. McC. Howell ◽  
G. A. J. Pitt ◽  
Catherine I. McLaughlin
Keyword(s):  
Retinoic Acid ◽  
Chick Embryo ◽  
Vitamin A ◽  
Progressive Failure ◽  
Vitamin A Deficiency ◽  
Sole Source ◽  
Retinyl Acetate ◽  
Histological Changes ◽  
Acid Methyl ◽  
Vitamin A Acid

1. Male and female chickens were reared from hatching on vitamin A-free diets, either unsupplemented or containing retinoic acid (vitamin A acid), methyl retinoate or retinyl acetate (vitamin A acetate). The birds given retinyl acetate grew well and had a normal appearance, but those given the unsupplemented diet died before 4 weeks of age after developing typical signs of avitaminosis A. The birds given retinoic acid or methyl retinoate did not show overt signs of vitamin A deficiency or other abnormalities except for a progressive failure of vision. Minimal histological changes were found in their retinas, and their vision was rapidly restored after feeding with retinyl acetate.2. The cocks maintained with retinoic acid or methyl retinoate had normal testes and the hens laid eggs at a normal rate, but although their eggs could be obtained fertile the development of the embryo became abnormal after 2 days incubation and it always died. The development of the embryos could be stimulated and sometimes restored to normal by injection of various forms of vitamin A into the eggs before incubation, or by previous administration of retinyl acetate to the hens.3. It is concluded that feeding retinoic acid as the sole source of vitamin A enables the hen to produce eggs that lack vitamin A but are otherwise normal, thus permitting the demonstration of a hitherto undescribed requirement of the early chick embryo for vitamin A.4. The toxicity of vitamin A derivatives to chick embryos was investigated; injected retinoic acid was found to be extremely toxic.

Vitamin A Status and Hepatic Drug Metabolism in the Rat

1973 ◽  
Vol 51 (1) ◽  
pp. 6-11 ◽  
Author(s):  
G. C. Becking
Keyword(s):  
Vitamin A ◽  
Drug Metabolism ◽  
Vitamin A Deficiency ◽  
Hepatic Drug Metabolism ◽  
Deficient Diet ◽  
Hepatic Drug ◽  
Vitamin A Status ◽  
Cytochrome P 450 ◽  
Liver Vitamin

The effect of vitamin A status on hepatic drug metabolism was studied in rats. Animals were fed diets with and without vitamin A for 20 and 25 days. Weight gains of control and deficient animals were not significantly different, whereas liver vitamin A levels had decreased to less than 10% of control animals after 20 days and were essentially zero after eating the deficient diet for 25 days. Aniline metabolism in vitro and aminopyrine metabolism in vitro and in vivo were significantly lower in male weanling rats fed a vitamin A deficient diet for 20 days. No alteration in in vitro p-nitrobenzoic acid metabolism was noted after 25 days on the test. Vitamin A deficiency did not alter microsomal protein levels or cytochrome c reductase activity but deficient animals did have a lower microsomal cytochrome P-450 content. Hepatic enzyme activities and cytochrome P-450 levels were restored to values approaching those found in control animals by feeding vitamin A deficient rats the vitamin A containing diet for 21 days. Liver vitamin A levels were markedly increased after re-feeding studies but were still significantly lower than control animals.

Complex regulation of TGF beta expression by retinoic acid in the vitamin A-deficient rat

Development ◽  
1991 ◽  
Vol 111 (4) ◽  
pp. 1081-1086 ◽  
Author(s):  
A.B. Glick ◽  
B.K. McCune ◽  
N. Abdulkarem ◽  
K.C. Flanders ◽  
J.A. Lumadue ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Vitamin A ◽  
Vitamin A Deficiency ◽  
Alveolar Epithelium ◽  
Tgf Beta ◽  
Basal Expression ◽  
Beta 2 ◽  
Complex Regulation ◽  
First Time

We report the results of a histochemical study, using polyclonal antipeptide antibodies to the different TGF beta isoforms, which demonstrates that retinoic acid regulates the expression of TGF beta 2 in the vitamin A-deficient rat. Basal expression of TGF beta 2 diminished under conditions of vitamin A deficiency. Treatment with retinoic acid caused a rapid and transient induction of TGF beta 2 and TGF beta 3 in the epidermis, tracheobronchial and alveolar epithelium, and intestinal mucosa. Induction of TGF beta 1 expression was also observed in the epidermis. In contrast to these epithelia, expression of the three TGF beta isoforms increased in vaginal epithelium during vitamin A deficiency, and decreased following systemic administration of retinoic acid. Our results show for the first time the widespread regulation of TGF beta expression by retinoic acid in vivo, and suggest a possible mechanism by which retinoics regulate the functions of both normal and pre-neoplastic epithelia.

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