Which vitamin is also known as Retinol or Retinal?
"vitamin A. This means that more continents are affected by the deficiency of vitamin A than was previously thought. Changing dietary choices in Africa, Asia, and South America will not be sufficient, and agricultural practices on those continents will need to change. The Food Standards Agency states that an average adult should not consume more than 1500 micrograms (5000 IU) per day, because this increases the chance of osteoporosis. During the absorption process in the intestines, retinol is incorporated into chylomicrons as the ester form, and it is these particles that mediate transport to the liver. Liver cells (hepatocytes) store"
"Vitamin A refers to retinyl palmitate and retinyl acetate. Retinyl acetate Retinyl acetate (retinol acetate, vitamin A acetate) is a natural form of vitamin A which is the acetate ester of retinol. It has potential antineoplastic and chemopreventive activities. In the United States, retinyl acetate is classified generally recognized as safe (GRAS) in the amounts used to fortify foods with vitamin A. World Health Organization recommendation on Maternal Supplementation During Pregnancy states that ""health benefits are expected for the mother and her developing fetus with little risk of detriment to either, from a daily supplement not exceeding 10,000IU [preformed] vitamin"
"Retinyl acetate Retinyl acetate (retinol acetate, vitamin A acetate) is a natural form of vitamin A which is the acetate ester of retinol. It has potential antineoplastic and chemopreventive activities. In the United States, retinyl acetate is classified generally recognized as safe (GRAS) in the amounts used to fortify foods with vitamin A. World Health Organization recommendation on Maternal Supplementation During Pregnancy states that ""health benefits are expected for the mother and her developing fetus with little risk of detriment to either, from a daily supplement not exceeding 10,000IU [preformed] vitamin A (3000mcg RE) at any time during pregnancy."" Preformed"
"Retinoic acid Retinoic acid is a metabolite of vitamin A (retinol) that mediates the functions of vitamin A required for growth and development. Retinoic acid is required in chordate animals, which includes all higher animals from fish to humans. During early embryonic development, retinoic acid generated in a specific region of the embryo helps determine position along the embryonic anterior/posterior axis by serving as an intercellular signaling molecule that guides development of the posterior portion of the embryo. It acts through Hox genes, which ultimately control anterior/posterior patterning in early developmental stages. The key role of retinoic acid in embryonic"
"because its metabolite retinoic acid, plays an important role as a signal molecule in the development of several tisues and organs. Its natural precursor, β-carotene, is considered safe, whereas the consumption of animal liver can lead to malformation, as the liver stores lipophile vitamins, including retinol. Isotretinoin (13-cis-retinoic-acid; brand name Roaccutane), vitamine A analog, which is often used to treat severe acne, is such a strong teratogen that just a single dose taken by a pregnant woman (even transdermally) may result in serious birth defects. Because of this effect, most countries have systems in place to ensure that it is"
"Retinoid The retinoids are a class of chemical compounds that are vitamers of vitamin A or are chemically related to it. Retinoids have found use in medicine where they regulate epithelial cell growth. Retinoids have many important functions throughout the body including roles in vision, regulation of cell proliferation and differentiation, growth of bone tissue, immune function, and activation of tumor suppressor genes. Research is also being done into their ability to treat skin cancers. Currently, alitretinoin (9-""cis""-retinoic acid) may be used topically to help treat skin lesions from Kaposi's sarcoma. There are three generations of retinoids: Some authors consider"
"has been passed from unicellular to multicellular organisms including Homo sapiens. This vitamin was most likely selected by evolution for sensing light because retinal causes a shift in photoreceptor absorbance to the visible light range. This shift in absorbance is especially important for life on Earth because it generally matches the peak irradiance of sunlight on its surface. A second reason why retinal evolved to be vital for human vision is because it undergoes a large conformational change when exposed to light. This conformational change is believed to make it easier for the photoreceptor protein to distinguish between its silent"
"other mammals. The carotenes α-carotene and γ-carotene, due to their single retinyl group (β-ionone ring), also have some vitamin A activity (though less than β-carotene), as does the xanthophyll carotenoid β-cryptoxanthin. All other carotenoids, including lycopene, have no beta-ring and thus no vitamin A activity (although they may have antioxidant activity and thus biological activity in other ways). Animal species differ greatly in their ability to convert retinyl (beta-ionone) containing carotenoids to retinals. Carnivores in general are poor converters of dietary ionone-containing carotenoids. Pure carnivores such as ferrets lack β-carotene 15,15'-monooxygenase and cannot convert any carotenoids to retinals at all"
"is because retinol causes cells to swell with water (this is also the reason too much Vitamin A is toxic). This swelling also likely occurs during treatment with 13-cis retinoic acid (isotretnoin), a pharmaceutical for treating severe acne, amongst other conditions. In lab experiments it has been shown that all-trans retinoic acid down regulates human albumin production. Other albumin types include the storage protein ovalbumin in egg white, and different storage albumins in the seeds of some plants, including hemp. For patients with low blood volume, there is no evidence that albumin reduces mortality when compared with cheaper alternatives such"
"retinal, and retinoic acid. It is most well known for retinol’s imperative role in ensuring normal vision in mammals however retinoic acid is important in altering the expression of genes through nuclear receptors. The precursors for vitamin A are beta-carotenes which get converted to vitamin A, predominantly in the liver. Cats rely on preformed vitamin A in the diet as they are unable to carry out the conversion of beta-carotenes to vitamin A. Vitamin A recommendations are 6668 IU/kg for a feline in a growing or reproductive state and 3332 IU/kg for adult maintenance. A maximum vitamin A intake of"
"can be represented as two connected retinyl groups, which are used in the body to contribute to vitamin A levels. Alpha-carotene and gamma-carotene also have a single retinyl group, which give them some vitamin activity. None of the other carotenes have vitamin activity. The carotenoid beta-cryptoxanthin possesses an ionone group and has vitamin activity in humans. Vitamin A can be found in two principal forms in foods: Vitamin A deficiency is estimated to affect approximately one third of children under the age of five around the world. It is estimated to claim the lives of 670,000 children under five annually."
"light emitted by the moon during the night. It can be extrapolated that the high ratio of rods to cones present in modern human eyes was retained even after the shift from nocturnal back to diurnal. Vitamin A is necessary for proper functioning of the human eye. The photopigment rhodopsin found in human rod cells is composed of retinal, a form of vitamin A, bound to an opsin protein. Upon the absorption of light rhodopsin was decomposed into retinal and opsin through bleaching. Retinal could then have one of two fates: it could recombine with opsin to reform rhodopsin or"
"it could be converted into free retinol. The American scientist George Wald was the first to recognize that the visual system expends vitamin A and is dependent upon diet for its replacement. Vitamin A serves many functions in the human body outside of healthy vision. It is vital in maintaining a healthy immune system as well as promoting normal growth and development. The average adult male and female should consume 900 and 700 micrograms of vitamin A per day, respectively. Consumption above 3000 micrograms per day is referred to as vitamin A toxicity and is usually caused by accidental ingestion"
"Pyritinol Pyritinol also called pyridoxine disulfide or pyrithioxine (European drug names Encephabol, Encefabol, Cerbon 6) is a semi-synthetic water-soluble analog of vitamin B (Pyridoxine HCl). It was produced in 1961 by Merck Laboratories by bonding 2 vitamin B compounds (pyridoxine) together with a disulfide bridge. Since the 1970s, it has been a prescription and OTC drug in several countries for cognitive disorders, rheumatoid arthritis, and learning disorders in children. Since the early 1990s it has been sold as a nootropic dietary supplement in the United States. It is approved for ""symptomatic treatment of chronically impaired brain function in dementia syndromes"""
"of supplements. Vitamin A is present in both animal and plant sources as retinoids and carotenoids, respectively. Retinoids can be used immediately by the body upon absorption into the cardiovascular system; however, plant-based carotenoids must be converted to retinol prior to utilization by the body. The highest animal-based sources of vitamin A are liver, dairy products, and fish. Fruits and vegetables containing high amounts of carotenoids are dark green, yellow, orange, and red in colour. Vitamin A-based opsin proteins have been used for sensing light in organisms for most of evolutionary history beginning approximately 3 billion years ago. This feature"
"""retinaldehyde"", is a light-sensitive molecule found in the rods and cones of the retina. Retinal is the fundamental structure involved in the transduction of light into visual signals, i.e. nerve impulses in the ocular system of the central nervous system. In the presence of light, the retinal molecule changes configuration and as a result a nerve impulse is generated. The information about the image via the eye is transmitted to the brain along the optic nerve. Different populations of ganglion cells in the retina send information to the brain through the optic nerve. About 90% of the axons in the"
"micronutrient that affects eyesight, cell differentiation, immune system function, bone growth, and tumor suppression. Retinol absorption and metabolism depends on lipocalins that act as binding proteins. Retinyl esters (present in meats) and beta-carotene (present in plants) are the two main sources of retinoids in the diet. After intake, they are converted to retinol, successively metabolized, and finally bound to retinol binding proteins (lipocalins) in the blood plasma. Because lipocalins are extracellular proteins, their intracellular effects are not obvious, and demand further study. However, lipophilic ligands, present as substituents to the lipocalins, have the ability to enter the cell, where they"
"enzyme preferentially hydrolyzes retinyl esters containing a long-chain fatty acid such as palmitate or stearate. Retinol enters the absorptive cells of the small intestine, preferentially in the all-trans-retinol form. Retinoids are used in the treatment of many diverse diseases and are effective in the treatment of a number of dermatological conditions such as inflammatory skin disorders, skin cancers, disorders of increased cell turnover (e.g. psoriasis), photoaging, and skin wrinkles Common skin conditions treated by retinoids include acne and psoriasis. Isotretinoin is not only considered the only known possible cure of acne in some patients, but was originally a chemotherapy treatment"
"Isotretinoin Isotretinoin, also known as 13-""cis""-retinoic acid (and colloquially referred to by its former brand name Accutane or Roaccutane), is a medication primarily used to treat severe acne. Rarely, it is also used to prevent certain skin cancers (squamous-cell carcinoma), and in the treatment of other cancers. It is used to treat harlequin-type ichthyosis, a usually lethal skin disease, and lamellar ichthyosis. It is a retinoid, meaning it is related to vitamin A, and is found in small quantities naturally in the body. Its isomer, tretinoin, is also an acne drug. Isotretinoin is primarily used as a treatment for severe"
"skin but costs significantly more. Tazarotene is the most effective and expensive topical retinoid, but is not as well-tolerated. Retinol is a form of vitamin A that has similar but milder effects, and is used in many over-the-counter moisturizers and other topical products. Isotretinoin is an oral retinoid that is very effective for severe nodular acne, and moderate acne that is stubborn to other treatments. One to two months use is typically adequate to see improvement. Acne often resolves completely or is much milder after a 4–6 month course of oral isotretinoin. After a single course, about 80% of people"
"to prevent, delay, or attenuate the symptomatic clinical condition. This includes the following: retinoids (e.g. tretinoin), antioxidants (e.g. topical vitamin C, oral supplements, CoQ10, Lipoic acid), estrogens, growth factors and cytokines. There are various forms of topical retinoids. Tretinoin, a retinoid, is widely considered to be the most efficacious treatment for photoaging by dermatologists due to consistent evidence from several randomized clinical trials. Retinoids are vitamin A derivatives that bind to retinoic acid receptors (RARs) and retinoid X receptors (RXRs). Binding to these receptors induces a cascade of cellular processes that ultimately lead to increased collagen production and epidermal thickening,"
"enzyme to convert β-carotene to retinol. In other contexts, both β-carotene and retinol are simply considered to be different forms (vitamers) of vitamin A. Provitamin D is ergosterol, and provitamin D is 7-dehydrocholesterol. Menadione is a synthetic provitamin of vitamin K. Provitamin A provitamin is a substance that may be converted within the body to a vitamin. The term previtamin is a synonym. For example, ""Provitamin B5"" is a name for panthenol, which may be converted in the body to vitamin B (pantothenic acid). The term ""provitamin"" is used when it is desirable to label a substance with little or"
"juvenile animals. Current evidence suggests that tretinoin decreases cohesiveness of follicular epithelial cells, although the exact mode of action is unknown. Additionally, tretinoin stimulates mitotic activity and increased turnover of follicular epithelial cells. Tretinoin is better known by the brand name Retin-A. Topical glycosaminoglycans supplements can help to provide temporary restoration of enzyme balance to slow or prevent matrix breakdown and consequent onset of wrinkle formation. Glycosaminoglycans (GAGs) are produced by the body to maintain structural integrity in tissues and to maintain fluid balance. Hyaluronic acid is a type of GAG that promotes collagen synthesis, repair, and hydration. GAGs serve"
"A and vitamin C. Beta-Carotene is required to synthesize vitamin A and vitamin A is needed to synthesize retinol. A lack of retinol-binding protein is due to a lack of retinol which is required to trigger its production. The damaging effects of porphyrins interacting with iron, absorbing photons to then emit reactive oxygen species is the mechanism of action that results in the itchy, painful blisters that are common with PCT. The reactive oxygen species that are formed interact with and exhaust the antioxidants in the skin, primarily those of beta-Carotene, vitamin E, and vitamin C. Supplementation of these three"
"Fenretinide Fenretinide (4-hydroxy(phenyl)retinamide; 4-HPR) (INN) is a synthetic retinoid derivative. Retinoids are substances related to vitamin A. It has been investigated for potential use in the treatment of cancer, as well as in the treatment of cystic fibrosis, rheumatoid arthritis, acne, psoriasis, and has been found to also slow the production and accumulation of a toxin that leads to vision loss in Stargardt's patients. In cancer studies, Fenretinide treatment may cause ceramide (a wax-like substance) to build up in tumor cells and is associated with the accumulation of reactive oxygen species (ROS), resulting in cell death through apoptosis and/or necrosis."
"Retinoic acid receptor beta Retinoic acid receptor beta (RAR-beta), also known as NR1B2 (nuclear receptor subfamily 1, group B, member 2) is a nuclear receptor that in humans is encoded by the ""RARB"" gene. This gene encodes retinoic acid receptor beta, a member of the thyroid-steroid hormone receptor superfamily of nuclear transcriptional regulators. This receptor localizes to the cytoplasm and to subnuclear compartments. It binds retinoic acid, the biologically active form of vitamin A which mediates cellular signalling in embryonic morphogenesis, cell growth and differentiation. It is thought that this protein limits growth of many cell types by regulating gene"
"Benfotiamine Benfotiamine (rINN, or ""S""-benzoylthiamine ""O""-monophosphate) is a synthetic ""S""-acyl derivative of thiamine (vitamin B1). It is marketed as a dietary supplement in most of the developed world, and as a pharmaceutical drug in some countries for treating diabetic neuropathy under the trade name Milgamma and others. Combination drugs with pyridoxine or cyanocobalamin are also marketed in a few countries. Benfotiamine is primarily marketed as an antioxidant dietary supplement. In some countries it is marketed as a drug to treat diabetic neuropathy; clinical trials results are mixed, finding it mildly useful or no different from placebo. There is little published"
"is colorless. Riboflavin Riboflavin, also known as vitamin B, is a vitamin found in food and used as a dietary supplement. Food sources include eggs, green vegetables, milk and other dairy product, meat, mushrooms, and almonds. Some countries require its addition to grains. As a supplement it is used to prevent and treat riboflavin deficiency and prevent migraines. It may be given by mouth or injection. It is nearly always well tolerated. Normal doses are safe during pregnancy. Riboflavin is in the vitamin B group. It is required by the body for cellular respiration. Riboflavin was discovered in 1920, isolated"
"Institute of Medicine uses retinol activity equivalents (RAE) for their Dietary Reference Intakes, defined as follows: 1 µg RE = 1 µg retinol 1 µg RAE = 2 µg all-""trans""-β-carotene from supplements 1 µg RAE = 12 µg of all-""trans""-β-carotene from food 1 µg RAE = 24 µg α-carotene or β-cryptoxanthin from food RAE takes into account carotenoids' variable absorption and conversion to vitamin A by humans better than and replaces the older retinol equivalent (RE) (1 µg RE = 1 µg retinol, 6 µg β-carotene, or 12 µg α-carotene or β-cryptoxanthin). RE was developed 1967 by the United Nations/World"
"to receptor heterodimers. Antagonistic and synergistic interactions between these two vitamins have been reported, as they relate to skeletal health. Stimulation of bone resorption by vitamin A has been reported to be independent of its effects on vitamin D. Vitamin A exerts several toxic effects regarding redox environment and mitochondrial function Tests may include: Assessing vitamin A status in persons with subtoxicity or toxicity is complicated because serum retinol concentrations are not sensitive indicators in this range of liver vitamin A reserves. The range of serum retinol concentrations under normal conditions is 1–3 μmol/l and, because of homeostatic regulation, that"
"chronic hand eczema. The adverse effects observed were consistent with retinoid toxicity, and included severe headache, diarrhoea, facial flushing and hypertriglyceridemia. These effects were reversible. Alitretinoin is believed to be the endogenous ligand (a substance that naturally occurs in the body that activates this receptor) for retinoid X receptor, but it also activates the retinoic acid receptor. Alitretinoin Alitretinoin, or 9-cis-retinoic acid, is a form of vitamin A. It is also used in medicine as an antineoplastic (anti-cancer) agent developed by Ligand Pharmaceuticals. It is a first generation retinoid. Ligand gained Food and Drug Administration (FDA) approval for alitretinoin in"
"Retinyl palmitate is also a constituent of some topically applied skin care products. After its absorption into the skin, retinyl palmitate is converted to retinol, and ultimately to retinoic acid (the active form of vitamin A present in Retin-A). The Environmental Working Group (EWG) and New York Senator Chuck Schumer have called attention to the fact that high doses of topical retinyl palmitate were shown to accelerate cancer in lab animals, fueling the sunscreen controversy in the popular press. One toxicological analysis determined that ""there is no convincing evidence to support the notion that [retinyl palmitate] in sunscreens is carcinogenic."""
"the extracellular surface. However, Asp97 and Arg94 may replace this functionality without the close residue proximity as in bacteriorhodopsin. The department of chemistry at Syracuse University decisevely showed Asp97 cannot be the proton release group as the release happened at forcing conditions under which the aspartic acid group remained protonated. The Rhodopsin haloprotein family shares the ligand Retinal, Vitamin A Aldehyde, one of the many types of Vitamin A. Retinal is a conjugated poly-unsaturatedchromophore (polyene), obtained from carnivorous diet or by the carotene pathway (β-carotene 15,15'-monoxygenase). Proteorhodopsin functions throughout the Earth's oceans as a light-driven H+ pump, by a mechanism"