Retinol is another name for which vitamin?
"cells through retinoid differentiation. Vitamin A affects the production of human growth hormone. Retinoic acid is required to bind to nuclear receptors to aid in growth. When referring to dietary allowances or nutritional science, retinol is usually measured in international units (IU). IU refers to biological activity and therefore is unique to each individual compound, however 1 IU of retinol is equivalent to approximately 0.3 micrograms (300 nanograms). This vitamin plays an essential role in vision, particularly night vision, normal bone and tooth development, reproduction, and the health of skin and mucous membranes (the mucus-secreting layer that lines body regions"
"Retinal Retinal is also known as retinaldehyde. It was originally called retinene, and renamed after it was discovered to be vitamin A aldehyde. Retinal is one of the many forms of vitamin A (the number of which varies from species to species). Retinal is a polyene chromophore, bound to proteins called opsins, and is the chemical basis of animal vision. Retinal allows certain microorganisms to convert light into metabolic energy. Vertebrate animals ingest retinal directly from meat, or they produce retinal from carotenoids, either from one of two carotenes (α-carotene, β-carotene) or from β-cryptoxanthin, a type of xanthophyll. These carotenoids"
"Retinene The Retinenes (Retinene and Retinene) are chemical derivatives of the dietary supplement vitamin A (see retinol) formed through oxidation reactions. Retinene is better known as retinaldehyde or simply retinal and is fundamental in the transduction of light into visual signals in the photoreceptor level of the retina (known as the visual cycle). Retinene is more formally known as dehydroretinaldehyde. The energy of impinging photons will convert retinaldehyde from an 11-cis isomer into an all-trans form. In the retina, this conversion induces a conformational change in the surrounding opsin protein pigment, leading to signaling through the G protein transducin. Retinaldehyde"
"isomerase activity. All-""trans""-retinal is also an essential component of type I, or microbial, opsins such as bacteriorhodopsin, channelrhodopsin, and halorhodopsin. In these molecules, light causes the all-""trans""-retinal to become 13-""cis"" retinal, which then cycles back to all-""trans""-retinal in the dark state. The American biochemist George Wald and others had outlined the visual cycle by 1958. For his work, Wald won a share of the 1967 Nobel Prize in Physiology or Medicine with Haldan Keffer Hartline and Ragnar Granit. Retinal Retinal is also known as retinaldehyde. It was originally called retinene, and renamed after it was discovered to be vitamin A"
"also forms a part of bacteriorhodopsin, a light-induced proton pump found in some archaea. Experimentally, it is possible to replace 11-cis retinaldehyde by perfusing retinal tissue preparations with retinaldehyde derivatives. Selective modification of the retinaldehyde structure, particularly the density of electrons in the π-orbitals, can lead to insights into the interaction between the retinaldehyde moiety and the surrounding pigment protein. ""The names of all these molecules have recently been changed ... vitamin A is now retinol, retinene is retinal; there is also retinoic acid""—George Wald (1967). Retinene The Retinenes (Retinene and Retinene) are chemical derivatives of the dietary supplement vitamin"
"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"
"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"
"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"
"(three forms/colors in humans), responsible for color vision and sensing relatively high light intensities (day vision), are less impaired at early stages of the vitamin A deficiency. All these protein-pigment complexes are located in the light-sensing cells in eye's retina. When stimulated by light, rhodopsin splits into a protein and a cofactor: opsin and all-""trans""-retinal (a form of vitamin A). The regeneration of active rhodopsin requires opsin and 11-""cis""-retinal. The regeneration of 11-""cis""-retinal occurs in vertebrates via a sequence of chemical transformations that constitute ""the visual cycle"" and which occurs primarily in the retinal pigmented epithelial cells. Without adequate amounts"
"must be obtained from plants or other photosynthetic organisms. No other carotenoids can be converted by animals to retinal, and some carnivores cannot convert any carotenoids at all. The other main forms of vitamin A, retinol, and a partially active form, retinoic acid, may both be produced from retinal. Invertebrates such as insects and squid use hydroxylated forms of retinal in their visual systems, which derive from conversion from other xanthophylls. Living organisms produce retinal (RAL) by irreversible oxidative cleavage of carotenoids. For example, catalyzed by a beta-carotene 15,15'-monooxygenase or a beta-carotene 15,15'-dioxygenase. Just as carotenoids are the precursors 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."
"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"
"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"
"of damage which can also be due to lack of vitamin A, but which is caused by lack of other forms of vitamin A which work in the visual system. Xerophthalmia from ""hypovitaminosis A"" is specifically due to lack of the hormone-like vitamin A metabolite retinoic acid, since (along with certain growth-stunting effects) the condition can be reversed in vitamin A deficient rats by retinoic acid supplementation (however the retinal damage continues). Since retinoic acid cannot be reduced to retinal or retinol, these effects on the cornea must be specific to retinoic acid. This is in keeping with retinoic acid's"
"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"""
"is composed of the 11-cis-retinal covalently linked via a Schiff base to the opsin protein (either rod opsin or blue, red or green cone opsins). The process of vision relies on the light-induced isomerisation of the chromophore from 11-""cis"" to all-""trans"" resulting in a change of the conformation and activation of the photoreceptor molecule. One of the earliest signs of vitamin A deficiency is night-blindness followed by decreased visual acuity. George Wald won the 1967 Nobel Prize in Physiology or Medicine for his work with retina pigments (also called visual pigments), which led to the understanding of the role of"
"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"
"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"
"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"
"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"
"Geritol Geritol is a United States trademarked name for various dietary supplements, past and present. Geritol is a brand name for several vitamin complexes plus iron or multimineral products in both liquid form and tablets, containing from 9.5 to 18 mg of iron per daily dose. The name conveys a connection with aging, as in ""geriatric."" The product has been promoted from almost the beginning of the mass media era as a cure for ""iron-poor tired blood"". Geritol was introduced as an alcohol-based, iron and B vitamin tonic by Pharmaceuticals, Inc., in August 1950 and primarily marketed as such into"
"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"
"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"
"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."
"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"
"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"
"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"
"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 February 1999. In the United States, topical alitretinoin (in the form of a gel; trade name Panretin) is indicated for the treatment of skin lesions in AIDS-related Kaposi's sarcoma. Alitretinoin is not indicated when systemic therapy against Kaposi's sarcoma is required. It has received EMA (11 October 2000) and FDA (2 March 1999) approval for this indication."
"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,"
"Carotenoid oxygenase Carotenoid oxygenases are a family of enzymes involved in the cleavage of carotenoids to produce, for example, retinol, commonly known as vitamin A. This family includes an enzyme known as RPE65 which is abundantly expressed in the retinal pigment epithelium where it catalyzed the formation of 11-cis-retinol from all-trans-retinyl esters. Carotenoids such as beta-carotene, lycopene, lutein and beta-cryptoxanthine are produced in plants and certain bacteria, algae and fungi, where they function as accessory photosynthetic pigments and as scavengers of oxygen radicals for photoprotection. They are also essential dietary nutrients in animals. Carotenoid oxygenases cleave a variety of carotenoids"
"applied to the skin. Retinoic acid, termed Tretinoin in clinical usage, is used in the treatment of acne and keratosis pilaris in a topical cream. An isomer of tretinoin, isotretinoin is also used orally (under the trade names ""Accutane"" and ""Roaccutane""), generally for severe or recalcitrant acne. Tretinoin, under the alternative name of all-trans retinoic acid (ATRA), is used as chemotherapy for acute promyelocytic leukemia, a subtype of acute myelogenous leukemia. This is because cells of this subtype of leukemia are sensitive to agonists of the retinoic acid receptors (RARs). Commercial production of retinol typically requires retinal synthesis through reduction"
"cell differentiation; amongst these are the differentiation of human embryonic stem cells to posterior foregut lineages and also to functional motor neurons. Vitamin A is converted by the protein RPE65 within the retinal pigment epithelium into 11-cis-retinal. This molecule is then transported into the photoreceptor cells of the retina, where it acts as a light-activated molecular switch within opsin proteins that activates a complex cascade called the visual cycle. This cycle begins with 11-cis retinal absorbing light and isomerizing into all-trans retinal. The change in shape of the molecule after absorbing light in turn changes the configuration of the complex"