Akademik

One of a group of organic substances, present in minute amounts in natural foodstuffs, that are essential to normal metabolism; insufficient amounts in the diet may cause deficiency diseases. [L. vita, life, + amine]

- v. A 1. any β-ionone derivative, except provitamin A carotenoids, possessing qualitatively the biological activity of retinol; deficiency interferes with the production and resynthesis of rhodopsin, thereby causing night blindness, and produces a keratinizing metaplasia of epithelial cells that may result in xerophthalmia, keratosis, susceptibility to infections, and retarded growth; 2. the original v. A, now known as retinol. SYN: axerophthol.

- v. A₁ SYN: retinol.

- v. A₂ SYN: dehydroretinol.

- v. A₁ acid SYN: retinoic acid.

- v. A₁ alcohol SYN: retinol.

- v. A aldehyde SYN: retinaldehyde.

- v. A₂ aldehyde SYN: dehydroretinaldehyde.

- antiberiberi v. SYN: thiamin.

- antihemorrhagic v. SYN: v. K.

- antineuritic v. SYN: thiamin.

- antirachitic vitamins ergocalciferol (v. D₂) and cholecalciferol (v. D₃).

- antiscorbutic v. SYN: ascorbic acid.

- antisterility v. SYN: v. E (2).

- v. B a group of water-soluble substances originally considered as one v..

- v. B₁ SYN: thiamin.

- v. B₂ 1. SYN: riboflavin. 2. obsolete term for a complex of folic acid, nicotinic acid, nicotinamide, pantothenic acid, and riboflavin.

- v. B₃ 1. obsolete term for nicotinamide and/or nicotinic acid; 2. obsolete term for pantothenic acid.

- v. B₄ 1. once believed to be a factor necessary for nutrition of the chick, now identified simply as certain essential amino acid s and/or adenine; 2. obsolete term for adenine.

- v. B₅ term once used to describe biologic activities now ascribed to pantothenic acid or nicotinic acid.

- v. B₆ pyridoxine and related compounds (pyridoxal; pyridoxamine).

- v. B₁₂ generic descriptor for compounds exhibiting the biological activity of cyanocobalamin (cyanocob(III)alamin); the antianemia factor of liver extract that contains cobalt, a cyano group, and corrin in a cobamide structure. Several substances with similar formulas and with the characteristic hematinic action have been isolated and designated: B_12a, hydroxocobalamin; B_12b, aquacobalamin; B_12c, nitritocobalamin; B_12r, cob(II)alamin; B_12s, cob(I)alamin; B_12III, factors A and V_1a (cobyric acid) and pseudovitamin B₁₂. Vitamins B_12a and B_12b are known to be tautomeric compounds; B_12b has been obtained from cultures of Streptomyces aureofaciens; B_12c has been obtained from cultures of Streptomyces griseus and is distinguishable from B₁₂ by differences in its absorption spectrum. The physiologically active v. B₁₂ coenzymes are methylcobalamin and deoxyadenosinecobalamin. A deficiency of v. B₁₂ is often associated with certain methylmalonic aciduria s. SYN: animal protein factor, antianemic factor, antipernicious anemia factor (1), erythrocyte maturation factor, maturation factor, methylcobalamin.

- v. B_T SYN: carnitine.

- v. B_x SYN: p-aminobenzoic acid.

- v. B complex a pharmaceutical term applied to drug products containing a mixture of the B vitamins, usually B₁, B₂, B₃, B₅, and B₆.

- v. B_c conjugase an enzyme catalyzing the hydrolysis of the pteroylpolyglutamic acids to pteroylmonoglutamic acid, with consequent increase in v. activity; v. B_c is an obsolete term for folic acid.

- v. B₁₂ with intrinsic factor concentrate a combination of v. B₁₂ with suitable preparations of the mucosa of the stomach or intestine of domestic animals used for food by humans.

- v. C SYN: ascorbic acid.

- coagulation v. obsolete term for v. K.

- v. D generic descriptor for all steroids exhibiting the biologic activity of ergocalciferol or cholecalciferol, the antirachitic vitamins popularly called the “sun-ray vitamins.” They promote the proper utilization of calcium and phosphorus, thereby producing growth, together with proper bone and tooth formation, in young children; the sulfate, a water-soluble conjugate, is found in the aqueous phase of human milk; v. D₁ is a 1:1 mixture of lumisterol and v. D₂.

- v. D₂ SYN: ergocalciferol.

- v. D₃ SYN: cholecalciferol.

- v. E 1. SYN: α-tocopherol. 2. generic descriptor of tocol and tocotrienol derivatives possessing the biologic activity of α-tocopherol; contained in various oils (wheat germ, cotton seed, palm, rice) and whole grain cereals where it constitutes the nonsaponifiable fraction; also contained in animal tissue (liver, pancreas, heart) and lettuce; deficiency produces resorption or abortion in female rats and sterility in males. SYN: antisterility factor, antisterility v., fertility v..

- v. F term sometimes applied to the essential unsaturated fatty acid s, linoleic, linolenic, and arachidonic acid s.

- fat-soluble vitamins those vitamins, soluble in fat solvents (nonpolar solvents) and relatively insoluble in water, marked in chemical structure by the presence of large hydrocarbon moieties in the molecule; e.g., vitamins A, D, E, K.

- fertility v. SYN: v. E (2).

- v. G obsolete term for riboflavin.

- v. H SYN: biotin. [Ger, H for Haut, skin]

- v. K generic descriptor for compounds with the biologic activity of phylloquinone; fat-soluble, thermostable compounds found in alfalfa, hog liver, fish meal, and vegetable oils, essential for the formation of normal amounts of prothrombin. SYN: antihemorrhagic factor, antihemorrhagic v..

- v. K₁, v. K₁(20) SYN: phylloquinone.

- v. K₂, v. K₂(30) SYN: menaquinone-6.

- v. K₃ SYN: menadione.

- v. K₄ SYN: menadiol diacetate.

- v. K₅ an antihemorrhagic v..

- v. K₂(35) SYN: menaquinone-7.

- microbial v. a substance necessary for the growth of certain microorganisms, e.g., biotin, p-aminobenzoic acid.

- v. P a mixture of bioflavonoids extracted from plants (especially citrus fruits). It reduces the permeability and fragility of capillaries and is useful in the treatment of certain cases of purpura that are resistant to v. C therapy. SEE ALSO: hesperidin, quercetin, rutin. SYN: capillary permeability factor, citrin, permeability v..

- permeability v. SYN: v. P.

- v. PP SYN: nicotinic acid.

- v. U term given to a factor in fresh cabbage juice that encourages the healing of peptic ulcer, (3-amino-3-carboxypropyl)dimethylsulfonium chloride, a methionine derivative.

vi·ta·min also vi·ta·mine 'vīt-ə-mən, Brit also 'vit- n any of various organic substances that are essential in minute quantities to the nutrition of most animals and some plants, act esp. as coenzymes and precursors of coenzymes in the regulation of metabolic processes but do not provide energy or serve as building units, and are present in natural foodstuffs or are sometimes produced within the body

any of a group of substances that are required, in very small amounts, for healthy growth and development: they cannot be synthesized by the body and are therefore essential constituents of the diet. Vitamins are divided into two groups, according to whether they are soluble in water or fat. The water-soluble group includes the vitamin B complex and vitamin C; the fat-soluble vitamins are vitamins A, D, E, and K. Lack of sufficient quantities of any of the vitamins in the diet results in specific vitamin deficiency diseases.