Reaction Process: WikiPathways:WP4342
Vitamins A and D - action mechanisms related metabolites
find 9 related metabolites which is associated with chemical reaction(pathway) Vitamins A and D - action mechanisms
7-Dehydrocholesterol ⟶ Previtamin D3
Vitamin D3
Vitamin d3 appears as fine colorless crystals. Water insoluble. (NTP, 1992) Calciol is a hydroxy seco-steroid that is (5Z,7E)-9,10-secocholesta-5,7,10(19)-triene in which the pro-S hydrogen at position 3 has been replaced by a hydroxy group. It is the inactive form of vitamin D3, being hydroxylated in the liver to calcidiol (25-hydroxyvitamin D3), which is then further hydroxylated in the kidney to give calcitriol (1,25-dihydroxyvitamin D3), the active hormone. It has a role as a human metabolite and a geroprotector. It is a seco-cholestane, a hydroxy seco-steroid, a member of D3 vitamins, a secondary alcohol and a steroid hormone. Vitamin D, in general, is a secosteroid generated in the skin when 7-dehydrocholesterol located there interacts with ultraviolet irradiation - like that commonly found in sunlight. Both the endogenous form of vitamin D (that results from 7-dehydrocholesterol transformation), vitamin D3 (cholecalciferol), and the plant-derived form, vitamin D2 (ergocalciferol), are considered the main forms of vitamin d and are found in various types of food for daily intake. Structurally, ergocalciferol differs from cholecalciferol in that it possesses a double bond between C22 and C23 and has an additional methyl group at C24. Finally, ergocalciferol is pharmacologically less potent than cholecalciferol, which makes vitamin D3 the preferred agent for medical use. Appropriate levels of vitamin D must be upheld in the body in order to maintain calcium and phosphorus levels in a healthy physiologic range to sustain a variety of metabolic functions, transcription regulation, and bone metabolism. However, studies are also ongoing to determine whether or not cholecalciferol may also play certain roles in cancer, autoimmune disorders, cardiovascular disease, and other medical conditions that may be associated with vitamin D deficiency. Cholecalciferol is a Vitamin D. Cholecalciferol is a natural product found in Taiwanofungus camphoratus, Theobroma cacao, and other organisms with data available. Cholecalciferol is a steroid hormone produced in the skin when exposed to ultraviolet light or obtained from dietary sources. The active form of cholecalciferol, 1,25-dihydroxycholecalciferol (calcitriol) plays an important role in maintaining blood calcium and phosphorus levels and mineralization of bone. The activated form of cholecalciferol binds to vitamin D receptors and modulates gene expression. This leads to an increase in serum calcium concentrations by increasing intestinal absorption of phosphorus and calcium, promoting distal renal tubular reabsorption of calcium and increasing osteoclastic resorption. Cholecalciferol is only found in individuals that have used or taken this drug. It is a derivative of 7-dehydroxycholesterol formed by ultraviolet rays breaking of the C9-C10 bond. It differs from ergocalciferol in having a single bond between C22 and C23 and lacking a methyl group at C24. [PubChem]The first step involved in the activation of vitamin D3 is a 25-hydroxylation which is catalysed by the 25-hydroxylase in the liver and then by other enzymes. The mitochondrial sterol 27-hydroxylase catalyses the first reaction in the oxidation of the side chain of sterol intermediates. The active form of vitamin D3 (calcitriol) binds to intracellular receptors that then function as transcription factors to modulate gene expression. Like the receptors for other steroid hormones and thyroid hormones, the vitamin D receptor has hormone-binding and DNA-binding domains. The vitamin D receptor forms a complex with another intracellular receptor, the retinoid-X receptor, and that heterodimer is what binds to DNA. In most cases studied, the effect is to activate transcription, but situations are also known in which vitamin D suppresses transcription. Calcitriol increases the serum calcium concentrations by: increasing GI absorption of phosphorus and calcium, increasing osteoclastic resorption, and increasing distal renal tubula... Vitamin D3, also called cholecalciferol, is one of the forms of vitamin D. Vitamin D3 is a steroid hormone that has long been known for its important role in regulating body levels of calcium and phosphorus, in mineralization of bone, and for the assimilation of Vitamin A. It is structurally similar to steroids such as testosterone, cholesterol, and cortisol (although vitamin D3, itself, is a secosteroid). Vitamin D3 is a derivative of 7-dehydroxycholesterol formed by ultraviolet rays breaking the C9-C10 bond. It differs from ergocalciferol in having a single bond between C22 and C23 and lacking a methyl group at C24. Vitamin D3 can also come from dietary sources, such as beef liver, cheese, egg yolks, and fatty fish (PubChem). The first step involved in the activation of vitamin D3 is a 25-hydroxylation catalyzed by 25-hydroxylase in the liver and then by other enzymes. The mitochondrial sterol 27-hydroxylase catalyzes the first reaction in the oxidation of the side chain of sterol intermediates. The active form of vitamin D3 (calcitriol) binds to intracellular receptors that then function as transcription factors to modulate gene expression. Like the receptors for other steroid hormones and thyroid hormones, the vitamin D receptor has hormone-binding and DNA-binding domains. The vitamin D receptor forms a complex with another intracellular receptor, the retinoid-X receptor, and that heterodimer is what binds to DNA. In most cases studied, the effect is to activate transcription, but situations are also known in which vitamin D suppresses transcription. Calcitriol increases the serum calcium concentrations by (1) increasing GI absorption of phosphorus and calcium, (2) increasing osteoclastic resorption, and (3) increasing distal renal tubular reabsorption of calcium. Calcitriol appears to promote intestinal absorption of calcium through binding to the vitamin D receptor in the mucosal cytoplasm of the intestine. Subsequently, calcium is absorbed through the formation of a calcium-binding protein. Vitamin d, also known as colecalciferol or calciol, belongs to vitamin d and derivatives class of compounds. Those are compounds containing a secosteroid backbone, usually secoergostane or secocholestane. Thus, vitamin d is considered to be a secosteroid lipid molecule. Vitamin d is practically insoluble (in water) and an extremely weak acidic compound (based on its pKa). Vitamin d can be found in a number of food items such as dumpling, vinegar, chocolate, and margarine, which makes vitamin d a potential biomarker for the consumption of these food products. Vitamin d can be found primarily in blood and urine. Vitamin d is a non-carcinogenic (not listed by IARC) potentially toxic compound. Vitamin d is a drug which is used for the treatment of vitamin d deficiency or insufficiency, refractory rickets (vitamin d resistant rickets), familial hypophosphatemia and hypoparathyroidism, and in the management of hypocalcemia and renal osteodystrophy in patients with chronic renal failure undergoing dialysis. also used in conjunction with calcium in the management and prevention of primary or corticosteroid-induced osteoporosis. A - Alimentary tract and metabolism > A11 - Vitamins > A11C - Vitamin a and d, incl. combinations of the two > A11CC - Vitamin d and analogues COVID info from clinicaltrial, clinicaltrials, clinical trial, clinical trials D000077264 - Calcium-Regulating Hormones and Agents D018977 - Micronutrients > D014815 - Vitamins D050071 - Bone Density Conservation Agents Corona-virus Coronavirus SARS-CoV-2 COVID-19 SARS-CoV COVID19 SARS2 SARS
beta-Carotene
Beta-carotene is a cyclic carotene obtained by dimerisation of all-trans-retinol. A strongly-coloured red-orange pigment abundant in plants and fruit and the most active and important provitamin A carotenoid. It has a role as a biological pigment, a provitamin A, a plant metabolite, a human metabolite, a mouse metabolite, a cofactor, a ferroptosis inhibitor and an antioxidant. It is a cyclic carotene and a carotenoid beta-end derivative. Beta-carotene, with the molecular formula C40H56, belongs to the group of carotenoids consisting of isoprene units. The presence of long chains of conjugated double bonds donates beta-carotene with specific colors. It is the most abundant form of carotenoid and it is a precursor of the vitamin A. Beta-carotene is composed of two retinyl groups. It is an antioxidant that can be found in yellow, orange and green leafy vegetables and fruits. Under the FDA, beta-carotene is considered as a generally recognized as safe substance (GRAS). Beta-Carotene is a natural product found in Epicoccum nigrum, Lonicera japonica, and other organisms with data available. Beta-Carotene is a naturally-occurring retinol (vitamin A) precursor obtained from certain fruits and vegetables with potential antineoplastic and chemopreventive activities. As an anti-oxidant, beta carotene inhibits free-radical damage to DNA. This agent also induces cell differentiation and apoptosis of some tumor cell types, particularly in early stages of tumorigenesis, and enhances immune system activity by stimulating the release of natural killer cells, lymphocytes, and monocytes. (NCI04) beta-Carotene is a metabolite found in or produced by Saccharomyces cerevisiae. A carotenoid that is a precursor of VITAMIN A. Beta carotene is administered to reduce the severity of photosensitivity reactions in patients with erythropoietic protoporphyria (PORPHYRIA, ERYTHROPOIETIC). See also: Lycopene (part of); Broccoli (part of); Lycium barbarum fruit (part of). Beta-Carotene belongs to the class of organic compounds known as carotenes. These are a type of polyunsaturated hydrocarbon molecules containing eight consecutive isoprene units. Carotenes are characterized by the presence of two end-groups (mostly cyclohexene rings, but also cyclopentene rings or acyclic groups) linked by a long branched alkyl chain. Beta-carotene is therefore considered to be an isoprenoid lipid molecule. Beta-carotene is a strongly coloured red-orange pigment abundant in fungi, plants, and fruits. It is synthesized biochemically from eight isoprene units and therefore has 40 carbons. Among the carotenes, beta-carotene is distinguished by having beta-rings at both ends of the molecule. Beta-Carotene is biosynthesized from geranylgeranyl pyrophosphate. It is the most common form of carotene in plants. In nature, Beta-carotene is a precursor (inactive form) to vitamin A. Vitamin A is produed via the action of beta-carotene 15,15-monooxygenase on carotenes. In mammals, carotenoid absorption is restricted to the duodenum of the small intestine and dependent on a class B scavenger receptor (SR-B1) membrane protein, which is also responsible for the absorption of vitamin E. One molecule of beta-carotene can be cleaved by the intestinal enzyme Beta-Beta-carotene 15,15-monooxygenase into two molecules of vitamin A. Beta-Carotene contributes to the orange color of many different fruits and vegetables. Vietnamese gac and crude palm oil are particularly rich sources, as are yellow and orange fruits, such as cantaloupe, mangoes, pumpkin, and papayas, and orange root vegetables such as carrots and sweet potatoes. Excess beta-carotene is predominantly stored in the fat tissues of the body. The most common side effect of excessive beta-carotene consumption is carotenodermia, a physically harmless condition that presents as a conspicuous orange skin tint arising from deposition of the carotenoid in the outermost layer of the epidermis. Yellow food colour, dietary supplement, nutrient, Vitamin A precursor. Nutriceutical with antioxidation props. beta-Carotene is found in many foods, some of which are summer savory, gram bean, sunburst squash (pattypan squash), and other bread product. A cyclic carotene obtained by dimerisation of all-trans-retinol. A strongly-coloured red-orange pigment abundant in plants and fruit and the most active and important provitamin A carotenoid. D - Dermatologicals > D02 - Emollients and protectives > D02B - Protectives against uv-radiation > D02BB - Protectives against uv-radiation for systemic use A - Alimentary tract and metabolism > A11 - Vitamins > A11C - Vitamin a and d, incl. combinations of the two > A11CA - Vitamin a, plain D020011 - Protective Agents > D000975 - Antioxidants > D002338 - Carotenoids D018977 - Micronutrients > D014815 - Vitamins > D000072664 - Provitamins
Retinol(Vitamin A)
Vitamin A (retinol) is a yellow fat-soluble, antioxidant vitamin important in vision and bone growth. It belongs to the family of chemical compounds known as retinoids. Retinol is ingested in a precursor form; animal sources (milk and eggs) contain retinyl esters, whereas plants (carrots, spinach) contain pro-vitamin A carotenoids. Hydrolysis of retinyl esters results in retinol while pro-vitamin A carotenoids can be cleaved to produce retinal. Retinal, also known as retinaldehyde, can be reversibly reduced to produce retinol or it can be irreversibly oxidized to produce retinoic acid. Retinol and derivatives of retinol that play an essential role in metabolic functioning of the retina, the growth of and differentiation of epithelial tissue, the growth of bone, reproduction, and the immune response. Dietary vitamin A is derived from a variety of carotenoids found in plants. It is enriched in the liver, egg yolks, and the fat component of dairy products. Retinyl esters from animal-sourced foods (or synthesized for dietary supplements for humans and domesticated animals) are acted upon by retinyl ester hydrolases in the lumen of the small intestine to release free retinol. Retinol enters intestinal absorptive cells by passive diffusion. Absorption efficiency is in the range of 70 to 90\%. Humans are at risk for acute or chronic vitamin A toxicity because there are no mechanisms to suppress absorption or excrete the excess in urine.[5] Within the cell, retinol is there bound to retinol binding protein 2 (RBP2). It is then enzymatically re-esterified by the action of lecithin retinol acyltransferase and incorporated into chylomicrons that are secreted into the lymphatic system. Unlike retinol, β-carotene is taken up by enterocytes by the membrane transporter protein scavenger receptor B1 (SCARB1). The protein is upregulated in times of vitamin A deficiency. If vitamin A status is in the normal range, SCARB1 is downregulated, reducing absorption.[6] Also downregulated is the enzyme beta-carotene 15,15'-dioxygenase (formerly known as beta-carotene 15,15'-monooxygenase) coded for by the BCMO1 gene, responsible for symmetrically cleaving β-carotene into retinal.[8] Absorbed β-carotene is either incorporated as such into chylomicrons or first converted to retinal and then retinol, bound to RBP2. After a meal, roughly two-thirds of the chylomicrons are taken up by the liver with the remainder delivered to peripheral tissues. Peripheral tissues also can convert chylomicron β-carotene to retinol.[6][15] The capacity to store retinol in the liver means that well-nourished humans can go months on a vitamin A deficient diet without manifesting signs and symptoms of deficiency. Two liver cell types are responsible for storage and release: hepatocytes and hepatic stellate cells (HSCs). Hepatocytes take up the lipid-rich chylomicrons, bind retinol to retinol-binding protein 4 (RBP4), and transfer the retinol-RBP4 to HSCs for storage in lipid droplets as retinyl esters. Mobilization reverses the process: retinyl ester hydrolase releases free retinol which is transferred to hepatocytes, bound to RBP4, and put into blood circulation. Other than either after a meal or when consumption of large amounts exceeds liver storage capacity, more than 95\% of retinol in circulation is bound to RBP4.[15] Vitamin A is a fat-soluble vitamin, hence an essential nutrient. The term "vitamin A" encompasses a group of chemically related organic compounds that includes retinol, retinal (also known as retinaldehyde), retinoic acid, and several provitamin (precursor) carotenoids, most notably beta-carotene.[3][4][5][6] Vitamin A has multiple functions: essential in embryo development for growth, maintaining the immune system, and healthy vision, where it combines with the protein opsin to form rhodopsin – the light-absorbing molecule necessary for both low-light (scotopic vision) and color vision.[7] Vitamin A occurs as two principal forms in foods: A) retinol, found in animal-sourced foods, either as retinol or bound to a fatty acid to become a retinyl ester, and B) the carotenoids alpha-carotene, β-carotene, gamma-carotene, and the xanthophyll beta-cryptoxanthin (all of which contain β-ionone rings) that function as provitamin A in herbivore and omnivore animals which possess the enzymes that cleave and convert provitamin carotenoids to retinal and then to retinol.[8] Some carnivore species lack this enzyme. The other carotenoids have no vitamin activity.[6] Dietary retinol is absorbed from the digestive tract via passive diffusion. Unlike retinol, β-carotene is taken up by enterocytes by the membrane transporter protein scavenger receptor B1 (SCARB1), which is upregulated in times of vitamin A deficiency.[6] Storage of retinol is in lipid droplets in the liver. A high capacity for long-term storage of retinol means that well-nourished humans can go months on a vitamin A- and β-carotene-deficient diet, while maintaining blood levels in the normal range.[4] Only when the liver stores are nearly depleted will signs and symptoms of deficiency show.[4] Retinol is reversibly converted to retinal, then irreversibly to retinoic acid, which activates hundreds of genes.[9] Vitamin A deficiency is common in developing countries, especially in Sub-Saharan Africa and Southeast Asia. Deficiency can occur at any age but is most common in pre-school age children and pregnant women, the latter due to a need to transfer retinol to the fetus. Vitamin A deficiency is estimated to affect approximately one-third of children under the age of five around the world, resulting in hundreds of thousands of cases of blindness and deaths from childhood diseases because of immune system failure.[10] Reversible night blindness is an early indicator of low vitamin A status. Plasma retinol is used as a biomarker to confirm vitamin A deficiency. Breast milk retinol can indicate a deficiency in nursing mothers. Neither of these measures indicates the status of liver reserves.[6] The European Union and various countries have set recommendations for dietary intake, and upper limits for safe intake. Vitamin A toxicity also referred to as hypervitaminosis A, occurs when there is too much vitamin A accumulating in the body. Symptoms may include nervous system effects, liver abnormalities, fatigue, muscle weakness, bone and skin changes, and others. The adverse effects of both acute and chronic toxicity are reversed after consumption of high dose supplements is stopped.[6]
7-Dehydrocholesterol
7-Dehydrocholesterol (7-DHC), also known as provitamin D3 or 5,7-cholestadien-3-b-ol, belongs to the class of organic compounds known as cholesterols and derivatives. Cholesterols and derivatives are compounds containing a 3-hydroxylated cholestane core. Thus, 7-dehydrocholesterol is also classified as a sterol. 7-Dehydrocholesterol is known as a zoosterol, meaning that it is a sterol isolated from animals (to distinguish those sterols isolated from plants which are called phytosterols). 7-DHC functions in the serum as a cholesterol precursor and is photochemically converted to vitamin D3 in the skin. Therefore 7-DHC functions as provitamin-D3. The presence of 7-DHC in human skin enables humans and other mammals to manufacture vitamin D3 (cholecalciferol) from ultraviolet rays in the sun light, via an intermediate isomer pre-vitamin D3. 7-DHC absorbs UV light most effectively at wavelengths between 290 and 320 nm and, thus, the production of vitamin D3 will occur primarily at those wavelengths (PMID: 9625080). The two most important factors that govern the generation of pre-vitamin D3 are the quantity (intensity) and quality (appropriate wavelength) of the UVB irradiation reaching the 7-dehydrocholesterol deep in the stratum basale and stratum spinosum (PMID: 9625080). 7-DHC is also found in the milk of several mammalian species, including cows (PMID: 10999630; PMID: 225459). It was discovered by Nobel-laureate organic chemist Adolf Windaus. 7-DHC can be produced by animals and plants via different pathways (PMID: 23717318). It is not produced by fungi in significant amounts. 7-DHC is made by some algae and can also be produced by some bacteria. 7-Dehydrocholesterol is a zoosterol (a sterol produced by animals rather than plants). It is a provitamin-D. The presence of this compound in skin enables humans to manufacture vitamin D3 from ultra-violet rays in the sun light, via an intermediate isomer provitamin D3. It is also found in breast milk. [HMDB] D018977 - Micronutrients > D014815 - Vitamins > D000072664 - Provitamins 7-Dehydrocholesterol is biosynthetic precursor of cholesterol and vitamin D3. 7-Dehydrocholesterol is biosynthetic precursor of cholesterol and vitamin D3.
Calcidiol
Calfcifediol is a prehormone that is produced in the liver by hydroxylation of vitamin D3 (cholecalciferol) by the enzyme cholecalciferol 25-hydroxylase. Calcifediol is then converted in the kidneys into calcitriol (1,25-(OH)2D3), a secosteroid hormone that is the active form of vitamin D. It can also be converted into 24-hydroxycalcidiol in the kidneys via 24-hydroxylation. [Wikipedia]. 25-Hydroxycholecalciferol is found in many foods, some of which are green zucchini, green bell pepper, red bell pepper, and other animal fat. The major circulating metabolite of vitamin D3 (calciferon). It is produced in the liver and is the best indicator of the bodys vitamin D stores. It is effective in the treatment of rickets and osteomalacia, both in azotemic and non-azotemic patients. Calcifediol also has mineralizing properties. A - Alimentary tract and metabolism > A11 - Vitamins > A11C - Vitamin a and d, incl. combinations of the two > A11CC - Vitamin d and analogues H - Systemic hormonal preparations, excl. sex hormones and insulins > H05 - Calcium homeostasis > H05B - Anti-parathyroid agents D018977 - Micronutrients > D014815 - Vitamins > D006887 - Hydroxycholecalciferols COVID info from clinicaltrial, clinicaltrials, clinical trial, clinical trials D050071 - Bone Density Conservation Agents Corona-virus Coronavirus SARS-CoV-2 COVID-19 SARS-CoV COVID19 SARS2 SARS
Previtamin D3
Previtamin D3 is an intermediate in the production of Vitamin D. [HMDB] Previtamin D3 is an intermediate in the production of Vitamin D.
9-cis-Retinoic acid
9-cis-Retinoic acid is an active retinoid that regulates expression of retinoid responsive genes, serving as a ligand for two classes of ligand-dependent transcription factors: the retinoic acid receptors and retinoid X receptors. Retinoids (vitamin A and its analogs) are essential dietary substances that are needed by mammals for reproduction, normal embryogenesis, growth, vision, and maintaining normal cellular differentiation and the integrity of the immune system. Within cells, retinoids regulate gene transcription acting through ligand-dependent transcription factors, the retinoic acid receptors (RARs), and the retinoid X receptors (RXRs). all-trans-Retinoic acid binds only to RARs with high affinity, whereas its 9-cis isomer binds with high affinity to both RARs and RXRs. The actions of all-trans- and 9-cis-retinoic acid in regulating cellular responses are distinct and not interchangeable (PMID: 9115228). Isolated from pancreas of pig and cow. Digestive enzyme. It is used in replacement therapy. It is used to prepare protein hydrolysates for pre- and post-operative diets D - Dermatologicals > D11 - Other dermatological preparations > D11A - Other dermatological preparations > D11AH - Agents for dermatitis, excluding corticosteroids L - Antineoplastic and immunomodulating agents > L01 - Antineoplastic agents > L01X - Other antineoplastic agents > L01XF - Retinoids for cancer treatment C274 - Antineoplastic Agent > C2122 - Cell Differentiating Agent > C1934 - Differentiation Inducer C274 - Antineoplastic Agent > C163758 - Targeted Therapy Agent > C804 - Retinoic Acid Agent C308 - Immunotherapeutic Agent > C129820 - Antineoplastic Immunomodulating Agent D020011 - Protective Agents > D000975 - Antioxidants > D002338 - Carotenoids D000970 - Antineoplastic Agents D003879 - Dermatologic Agents Same as: D02815
1,25-Dihydroxyvitamin D3-26,23-lactone
1,25-Dihydroxyvitamin D3-26,23-lactone (1,25(OH)2D3-26,23-lactone) is a vitamin D3 metabolite. The formation of 1,25(OH)2D3-26,23-lactone occurs in normocalcemic states and in situations in which 1,25(OH)2D3 has been administered. (PMID: 6324253). 1,25-dihydroxyvitamin D3 and (23S)-1,23,25-trihydroxyvitamin D3 are efficient precursors to 1,25(OH)2D3-26,23-lactone. 1,25(OH)2D3-26,23-lactone has an inhibitory action of bone resorption and the lactone ring plays a major part in its expression. (PMID: 6548386, 1666030). 1,25-Dihydroxyvitamin D3-26,23-lactone (1,25(OH)2D3-26,23-lactone) is a vitamin D3 metabolite. The formation of 1,25(OH)2D3-26,23-lactone occurs in normocalcemic states and in situations in which 1,25(OH)2D3 has been administered. (PMID: 6324253) D018977 - Micronutrients > D014815 - Vitamins > D004100 - Dihydroxycholecalciferols D018977 - Micronutrients > D014815 - Vitamins > D006887 - Hydroxycholecalciferols