create counter
Vitamin D and MS: Glossary
GLOSSARY OF VITAMIN D TERMS

Glossary A B C D E F G H I J K L M N O P Q R S T U V W X Y Z


A

Adequate Intake (AI)
of a nutrient, the amount that appears to sustain good health. The Food and Nutrition Board uses Adequate Intake for nutrients that have not yet received enough scientific study to merit setting of an official Recommended Dietary Allowance (RDA).
The 1997 Adequate Intake recommendations for vitamin D3 by the Food and Nutrition Board were as follows:

  • Infancy to age 50 years, 5 mcg (200 IU)/day;
  • Pregnant and lactating women, 10 mcg (400 IU)/day;
  • Adults 51 to 70 years, 10 mcg (400 IU)/day;
  • Adults 71 years and older, 15 mcg (600 IU)/day.
Vitamine D level [25(OH)D] of at least 75 nmol/L is recommended since 2006.
Source: Food and Nutrition Board, 1997

Analog (or Analogue)
a chemical compound structurally similar to another but differing often by a single element of the same valence and group of the periodic table as the element it replaces.
Source: Webster's Dictionary, 1988

Antagonism
opposition in physiological action; esp: interaction of two or more substances such that the action of any of one of them on living cells or tissues is lessened.
Source: Webster's Dictionary, 1988

Antirachitic
counteracting or preventing the development of rickets.
Source: Longman Dictionary of the English Language, 1984

Autocrine signalling
is a form of signalling in which a cell secretes a chemical messenger (called the autocrine agent) that signals the same cell.
Source: Wikipedia

Back to top


B

Biological responses
change in organism (or its parts) produced by change in its environment.
Source:The Penguin Dictionary of Biology, 2000

Biosynthesize
the production of a chemical compound by a living organism.
Source: Webster's Dictionary, 1988

Back to top


C

Calcification
the process of deposition of calcium salts. In the formation of bone this is a normal condition. In other organs, this could be an abnormal condition. Calcification of the aortic valve causes narrowing of the passage (aortic stenosis).
Source: Linus Pauling Institute

Calcidiol (or 25 Hydroxyvitamin D or 25(OH)D3 or 25(OH)D)
a prehormone, normally, the most abundant circulating metabolite of vitamin D3. It is produced in the liver and is the accepted indicator of vitamin D nutritional status. Clinical use of this is effective in the treatment of rickets and osteomalacia, both in azotemic and non-azotemic patients. 25(OH)D also has mineralizing properties.
Source: Reinhold Vieth

Calcifediol
a rarely used synonym for 25(OH)D.
Source: Anthony W Norman

Calciferol (or vitamin D2 or D3)
a synonym for either vitamin D3 or vitamin D2. In older literature, refers to vitamin D2.
Source: Anthony W Norman

Calciol
a synonym for calciferol.
Source: ?

Calcitonin (or Thyrocalcitinin)
a peptide hormone secreted by C-cells of the thyroid gland. Its effect is to direct calcium into bone, and it tends to lower the level of calcium in the blood plasma. It is also known as thyrocalcitinin. Biochemical assays of calcitonin mainly useful as a cancer marker. Calcitonin is gaining clinical acceptance as an osteoporosis treatment.
Source: Webster's Dictionary, 1988

Calcitriol (or 1,25 Dihydroxyvitamin D or 1α,25(OH)2D3 or 1,25(OH)2D)
the physiologically active metabolite of vitamin D. Circulating 1,25(OH)2D is formed primarily in the kidney by enzymatic hydroxylation of 25(OH)D. 1,25(OH)2D production is stimulated by hypocalcemia and parathyroid hormone. 1,25(OH)2D increases intestinal absorption of calcium.
Source: Reinhold Vieth

Calcium
the major inorganic component of bones and teeth. Ionized calcium is the most tightly regulated analyte in blood, with a coefficient of variation (SD/mean x 100%) of 3% among healthy humans. The total body content of an adult is about 1 – 1.5 kg (15 – 38 mol).
Source: Reinhold Vieth

Calmodulin
Ubiquitous calcium-binding protein whose binding to other proteins is governed by changes in intracellular Ca2+ concentration. Its binding modifies the activity of many target enzymes and membrane transport proteins.
Source: Molecular Biology of The Cell, 2002

Cholesterol
(1) cholesterol in animals and man is a precursor substance for all steroid hormones. In the skin of most animals, a specific precursor of cholesterol exists, 7-dehydrocholesterol, which is photolabile. The liver pathway for cholesterol synthesis cannot support vitamin D synthesis.
Source: Reinhold Vieth
(2) a lipid used in the construction of cell membranes and as a precursor in the synthesis of steroid hormones. Dietary cholesterol is obtained from animal sources, but cholesterol is also synthesized by the liver. Cholesterol is carried in the blood by lipoproteins (e.g., LDL and HDL). In atherosclerosis, cholesterol accumulates in plaques on the walls of some arteries.
Source: Linus Pauling Institute

Cholecalciferol see vitamin D3

Chronic disease
an illness lasting a long time. By definition of the U.S. Center for Health Statistics, a chronic disease is a disease lasting 3 months or more.
Source: Linus Pauling Institute

Cod liver oil
the oil from codfish liver; the classic source of vitamin A and D. Since the 18th century it has been used as a nutrient to help infants thrive. An average teaspoon-full contains 120-1200 mcg vitamin A and 1-10 mcg vitamin D per gram. British Pharmacopoeia standard: minimum 180 mcg vitamin A and 2 mcg vitamin D per gram.
Source: Reinhold Vieth

Colecalciferol see Cholecalciferol

Compound
a distinct substance formed by chemical union of two or more ingredients in definite proportion by weight.
Source: Webster's Dictionary, 1988

CYP24 see 24-Hydroxylase

CYP27B1 see 25-Hydroxylase

Cytochrome P-450
a class of enzymes that play important roles in the metabolism of drugs and toxins in the liver. They also play roles in the synthesis (formation) of steroid hormones in the adrenal cortex.
Source: Linus Pauling Institute

Cytokine
a protein or peptide made by cells that affects the behavior of other cells. Cytokines act on specific cytokine receptors in the cells they affect.
Source: Reinhold Vieth

Back to top


D

7-dehydrocholesterol
the precursor molecule of vitamin D3. This is produced in the skin of most animals, and secreted in the oils of the skin; however, cholesterol synthesis in the liver is primarily via a different pathway. 7-dehydrocholesterol is unstable to UVB light (285-300 nm), which breaks open the B-ring of the steroid, producing a secosteroid molecule, previtamin D, which spontaneously isomerizes to become vitamin D3.
Source: Reinhold Vieth

Dermis
the sensitive vascular inner mesodermic layer of the skin.
Source: http://www2.merriam-webster.com

DEXA
dual energy X-ray absorptiometry. A precise instrument that uses the energy from very small doses of X-rays to determine bone mineral density (BMD) and to diagnose and follow the treatment of osteoporosis.
Source: Linus Pauling Institute

Diabetes (diabetes mellitus)
a chronic condition associated with abnormally high levels of glucose (sugar) in the blood. The two types of diabetes are referred to as insulin-dependent (type 1) and non-insulin dependent (type 2). Type 1 diabetes results from a lack of adequate insulin secretion by the pancreas. Type 2 diabetes (also known as adult-onset diabetes) is characterized by an insensitivity of the tissues of the body to insulin secreted by the pancreas (insulin resistance).
Source: Linus Pauling Institute

Dietary reference intakes (DRIs)
nutrient-based reference values that can be used for planning and assessing diets and for many other purposes.
Source: Institute of Medicine, 1997

DRIP
an acronym "vitamin D-receptor interacting protein".
Source: Anthony W Norman

Back to top


E

Endocrine system
the glands and parts of glands that secrete hormones into the bloodstream to signal distant tissues, and that integrate and control the body's metabolic activity. Endocrine glands include the pituitary, thyroid, parathyroids, adrenals, pancreas, ovaries, and testes.
Source: Reinhold Vieth

Enrichment see fortification of food

Enzyme
a protein that catalyzes one or more biological reactions. That is, a substance that increases the speed of a chemical reaction without being changed in the overall process. Enzymes are vitally important to the regulation of the chemistry of cells and organisms.
Source: Reinhold Vieth

Epidermis
the outer nonsensitive and nonvascular layer of the skin of a vertebrate that overlies the dermis.
Source: Webster's Dictionary, 1988

Ergosterol
a lipid that can be extracted from certain forms plant life. Industrially it is extracted from yeast as a precursor which, when exposed to ultraviolet light, results in production of vitamin D2.
Source: Anthony W Norman

Ergocalciferol see vitamin D2

Back to top


F

Fortification of food (or enrichment)
the deliberate addition of specific nutrients to foods in order to increase their content, sometimes to a higher level than normal, as a means of providing the population with an increased level of intake. Generally synonymous with enrichment.
Source: Oxford dictionary of food and nutrition, 1995

Back to top


G

Gc-globulin see Vitamin D binding protein

Gene
a region of DNA that controls a specific hereditary characteristic, usually corresponding to a single protein.
Source: Linus Pauling Institute

Gene transcription
(DNA transcription); copying of one strand of DNA into a complementary RNA sequence by the enzyme RNA polymerase.
Source: Molecular Biology of The Cell, 2002

Generic term
being or having a nonproprietary name of a pharmaceutical.
Source: Webster's Dictionary, 1988

Back to top


H

1α-Hydroxylase (or P450c1 or CYP27B1)
?
Source: ?

24-Hydroxylase (or CYP24)
an enzyme 24-OHase: vitamin D3-24-hydroxylase??
Source: ?

25-Hydroxylase (P450C25 or Cyp2D25?)
(1) the enzyme in the liver that produces 25(OH)D, the major circulating form of vitamin D. This enzyme is not well regulated, and functions automatically; however, in severe liver disease production of 25(OH)D may be impaired, resulting in osteomalacia or vitamin D deficiency.
Source: Reinhold Vieth
(2) an enzyme 25-OHase: vitamin D3-25-hydroxylase??
Source: ?

25-Hydroxyvitamin D-1α-hydroxylase (or 1-OHase)
?
Source: ?

Hematopoietic
the formation of blood or of blood cells in the living body.
Source: Webster's Dictionary, 1988

Hormone
(1) a chemical messenger that is produced and secreted into the circulation by specific glands within the body of animals to signal organs that have specific receptor for the hormone. These target cells respond to hormone. Like cholesterol, vitamin D3 is not a hormone, but rather the raw material used to synthesize a hormone (see prehormone).
Source: Reinhold Vieth / Anthony W Norman

(2) an organic molecule, formed in one organ or part of the body and carried in the blood to another organ or part; depending on the specificity of their effects, hormones can alter the functional activity, and sometimes the structure, of just one organ or tissue or various numbers of them. [G. hormon, pres. part. of hormao, to rouse or set in motion]. Vitamin D is the raw material from which the hormone, 1,25-dihydroxyvitamin D, 1,25(OH)2D, is produced.
Source: Reinhold Vieth

Hormone D (or 1,25(OH)2D)
the parent vitamin D3 (an essential nutritional substance) and its steroid hormone daughter product 1,25(OH)2D (also referred to as hormone D).
Source: Journal of Steroid Biochemistry & Molecular Biology xxx (2007) xxx–xxx

Hypersensitivity
an exaggerated response to something. For example, for vitamin D, some people may possess 1-hydroxylase in non-renal locations that is either excessive or that releases its product into the circulation in an unregulated manner, so that increased supplies of vitamin D due to diet or sunshine cause hypercalcemia.
Source: Reinhold Vieth

Back to top


I

International Unit (IU) of vitamin D3
1.0 International Unit (IU) of vitamin D3 is 0.025 micrograms (mcg). The International Unit (IU) is still the most common way to express an amount of vitamin D for sale to the public. In nutrition microgram (mcg) is now prefered to International Unit (IU).
Source: Anthony W Norman

International Unit (IU) of 1,25(OH)2D
Has been operationally defined to be equivalent to 65 pmoles.
Source: Anthony W Norman, J. Nutrition 102:1709-1718 (1972)

Irradiation
exposure to radiation (as ultraviolet light, X-rays, or alpha particles).
Source: http://www2.merriam-webster.com

Back to top


L

Ligand
any molecule that binds to a specific site on a protein or other molecule.
Source: ?

Back to top


M

Metabolic
relating to or based on metabolism.
Source: Webster's Dictionary, 1988

Metabolism
the sum of the processes (reactions) by which a substance is assimilated and incorporated into the body or detoxified and excreted from the body.
Source: Linus Pauling Institute

Metabolism of vitamin D3
the series of steps from liver 25-hydroxylation of vitamin D3 into 25(OH)D, to renal 1-hydroxylation of 25(OH)D into 1,25(OH)2D, and the eventual breakdown of all vitamin D compounds.
Source: Reinhold Vieth

Metabolite
the product of a change in a molecule by metabolism in the body into another compound is said to be a metabolite of that molecule.
Source: Reinhold Vieth

Microgram (mcg)
one millionth of a gram.
Source: http://www2.merriam-webster.com

Mitochondria
energy-producing structures within cells. Mitochondria possess two sets of membranes, a smooth continuous outer membrane, and an inner membrane arranged in folds. Among other critical functions, mitochondria convert nutrients into energy via the electron transport chain.
Source: Linus Pauling Institute

Back to top


N

Neuroactive steroid
steroids that affect brain function via any mechanism and irrespective of site of formation
Source: Bruce S. McEwen in Basic Neurochemistry, sixth edition

Nuclear receptor
which, on binding an intracellular ligand, can bind a specific nuclear chromatin region and inhibit/enhance transcription of target genes.
Source: The Penguin Dictionary of Biology, 2000

Back to top


O

Osteomalacia
a disease condition of decreased bone mineral density characterized by dispersed areas of unmineralized bone due bone resorption, followed by the laying down of bone protein matrix. However, the disease pathology is that matrix deposition is not followed by mineralization of the matrix. Osteomalacia is characteristic of vitamin D deficiency in adults, while children with vitamin D deficiency suffer from rickets because the unmineralized bone in children is specific to the area of the growth plate, malformation on the scale of the whole bone. Osteomalacia is curable with proper nutrition, especially with vitamin D. Nutritional deficiency rickets is curable if treated early enough.
Source: Reinhold Vieth

Osteopontin
is a glycoprotein first identified in 1986 in osteoblasts. The prefix of the word "osteo" indicates that the protein is expressed in bone. Osteopontin is an extracellular structural protein and therefore an organic component of bone. Synonyms for this protein include sialoprotein I and 44K BPP (bone phosphoprotein).
Source: Wikipedia

Osteoporosis
a disease a condition of increased bone porosity and susceptibility to bone fracture due to a loss of bone mineral density (BMD). This is due to an imbalance between the natural process of bone resorption and bone formation. Normally these processes balance each other, but in older adults there is a progressive net loss of bone. What bone there is, is normal in its matrix and mineral makeup. There is no cure for osteoporosis, and treatments generally only preserve bone.
Source: Reinhold Vieth

Back to top


P

Paracrine
descriptive to characterize the within-tissue signaling with molecules from one cell to other cells in the tissue. Many tissues in the body produce 1,25(OH)2D which is thought to serve as an autocrine molecule, without entering the bloodstream. Similar to autocrine, but differs from it because different cell types may be affected.
Source: Reinhold Vieth

Parathyroid hormone (PTH)
an 81-amino acid peptide hormone of the parathyroid glands. PTH functions in concert with vitamin D and calcitonin in control of blood calcium levels.
Source: Reinhold Vieth

Phosphate
a salt of phosphoric acid. 85% of the body’s phosphate occurs in inorganic form with calcium as hydroxyapatite. In plasma or serum, most phosphate exists in the inorganic form as mono- and dihydrogen forms HPO4— or H2PO4-. Within cells, phosphate is an integral component of cell structures and high-energy compounds.
Source: Reinhold Vieth

Precursor
a molecule which is an ingredient, reactant, or intermediate in a synthetic pathway for a particular product.
Source: Linus Pauling Institute

Prehormone
a glandular secretory product, having little or no inherent biologic potency, that is converted peripherally to an active hormone. The classic examples are dehydroepiandrosterone, tetraiodothyronine (T4), but this term also applies to 25(OH)D (25-hydroxyvitamin D or calcidiol).
Source: Reinhold Vieth

Prohormone
an intraglandular precursor of a hormone. eg. pro-PTH, pro-Insulin, pro-opiocortin. While some describe vitamin D3 as a “prohormone”, this is not correct in the traditional context of the word, and “prohormone” is more appropriate for 25(OH)D.
Source: Reinhold Vieth

Back to top


R

RDA
recommended dietary allowance (rda) is the average daily dietary intake level that is sufficient to meet the nutrient requirements of nearly all (97 to 98 percent) individuals in a life stage and gender group. The RDA applies to individuals not to groups.
Source: Institute of Medicine

Recommended Dietary Allowance (RDA) of vitamin D
none has been estblished (see instead Adequate Intake).
Source: ?

Renal ferredoxin reductase
Source: ?

Renal ferredoxin
Source: ?

Rickets
(1) a deficiency disease that affects the young during the period of skeletal growth, is characterizezed esp. by soft and deformed bones, and is caused by failure to assimilate and use calcium and phosphorus normally due to inadequate sunlight or vitamin D.
Source: Webster's Dictionary, 1988
(2) often the result of vitamin D deficiency. Rickets affects children while their bones are still growing. It is characterized by soft and deformed bones, and is the result of a impaired incorporation of calcium and phosphate into the skeleton.
Source: Linus Pauling Institute

Back to top


S

Seco-steroids
Source: ?

Steroid hormones
aldosterone, cortisol, ecdysterone, estradiol, progesterone and testosterone a molecule related to cholesterol. Many important hormones such as estrogen and testosterone are steroids (see hormone).
Source: Linus Pauling Institute

Supplement
a nutrient or phytochemical supplied in addition to that which is obtained in the diet.
Source: Linus Pauling Institute

Back to top


T

Target organs
Source: ?

Transcription
(DNA transcription); the process by which one strand of DNA is copied into a complementary sequence of RNA.
Source: Linus Pauling Institute

Transcription factor
generally a protein that functions to initiate, enhance, or inhibit the transcription of a gene. Transcription factors can regulate the formation of a specific protein encoded by a gene.
Source: Linus Pauling Institute

Threshold value of vitamin D-deficiency
a serum 25(OH)D (25-hydroxyvitamin D) concentration > 75 nmol/L
Source: Reinhold Vieth

Back to top


U

Ultraviolet B (UV-B)
one of the three types of invisible light rays (together with ultraviolet A and ultraviolet C) given off by the sun.
Source: Webster's New World Medical Dictionary

Ultraviolet light
ultraviolet radiation
Source: Webster's Dictionary, 1988

Back to top


V

Vitamin
the term vitamin is derived from the words vital and amine, because vitamins are required for life and were originally thought to be amines. Although not all vitamins are amines, they are organic compounds required by humans in small amounts from the diet. An organic compound is considered a vitamin if a lack of that compound in the diet results in overt symptoms of deficiency.
Source: Linus Pauling Institute
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]. Note, it is not strictly necessary that a vitamin be only available through the diet. Note that beta-carotene permits production of vitamin A in the body, and niacin is also produced from precursors.
Source: ?

Vitamin D
(1) a precursor of a steroid hormone [1,25(OH)2D] in higher animals, including humans.
Source: Anthony W Norman
(2) Vitamin D is not a hormone because, like cholesterol, it is the raw material from which a hormone is synthesized.
Source: Anthony W Norman
(3) the physiological seco-steroid compound, vitamin D3, or the synthetic seco-steroid, vitamin D2. The “sunshine vitamin”. Vitamin D is not a hormone because it is 2 metabolic steps away from the recognized hormonal metabolite, 1,25(OH)2D, or 1,25-dihydroxyvitamin D. Vitamin D3 can be isolated from fish liver oils, or synthesized from 7-dehydrocholesterol obtained for example, from sheep wool.
Source:
(4) two chemical forms of vitamin D have been recognized traditionally, namely vitamin D2 and vitamin D3. However, the form naturally found in the blood of animals and man is vitamin D3. A synthetic compound, vitamin D2, is derived from the yeast sterol ergosterol by chemical procedures. Vitamin D2 and its metabolites are only detected in the circulation they have been consumed from artificial sources.
Source: Anthony W Norman
(5) Vitamin D has been used as a generic term to indicate a molecule of the general structure shown for rings A, B, C, and D with differing side chain structures. However, this practice has been misleading.
Source: ?

Vitamin D2 (ergocalciferol)
official name of vitamin D2:
9,10-seco(5Z,7E)-5,7,10(19)22-ergostatetraene-3b-ol

(1) an alternative vitamin D2 is derived from the yeast sterol ergosterol by chemical procedures.
(2) vitamin D2 has a markedly lower potency and shorter duration of action relative to vitamin D3.
Source: J Clin Endocrinol Metab 89: 5387–5391, 2004
(3) a synthetic, plant-derived molecule with a structure different from vitamin D3, but which has officially been accepted as a suitable substitute for vitamin D3 because studies in the 1930’s could not distinguish its antirachitic activity from vitamin D3. Recent research shows major differences between vitamin D2 and vitamin D3, to the point that most experts now contend vitamin D2 should no longer be regarded as a substitute for vitamin D3 in nutrition.
Source: Reinhold Vieth

Vitamin D3 (or cholecalciferol)
official name of vitamin D3:
9,10-seco(5Z,7E)-5,7,10(19)cholestatriene-3b-ol

the natural form of vitamin D for animals and man, produced in their bodies from cholesterol and 7-dehydrocholesterol.
(1) a vitamin in the truest sense of the word, because “insufficient amounts in the diet may cause deficiency diseases”.
(2) insufficient amounts in the diet may cause deficiency diseases.
Source: Reinhold Vieth
(3) an alcohol C27H44O that is the predominating form of vitamin D in most fish-liver oils, and it is formed in the skin on exposure to sunlight or ultraviolet rays.
Source: Anthony W Norman

Vitamin D-binding protein (DBP) (or Gc-globulin)
an alpha-globulin found in the plasma of man and other vertebrates. It is synthesized in the liver and carries vitamin D and its metabolites through the circulation and mediates the response of tissue. It is also known as group-specific component (Gc), the most genetically diverse protein in human circulation. Gc subtypes are used to determine specific phenotypes and gene frequencies. These data are employed in the classification of population groups, paternity investigations, and in forensic medicine.
Source: ?

Vitamin D compounds

Vitamin D deficiency
a subjective term to denote a severe lack of vitamin D, most typically, the concentration of the nutritionally relevant metabolite, 25-hydroxyvitamin D, 25(OH)D, associated with nutritional rickets or osteomalacia.
(1) Parfit has defined as a serum 25(OH)D concentration < 25 nmol/L (10 ng/mL) as diagnostic of vitamin D-deficiency rickets.
(2) a nutritional condition produced by a deficiency of vitamin D in the diet, insufficient production of vitamin D in the skin, inadequate absorption of vitamin D from the diet, or abnormal conversion of vitamin D to its bioactive metabolites. It is manifested clinically as rickets in children and osteomalacia in adults. (From Cecil Textbook of Medicine, 19th ed, p1406). Vitamin D is effective in the treatment of rickets and osteomalacia, both in azotemic and non-azotemic patients.
(3) the classic deficiency state resulting from a dietary absence of vitamin D3 or lack of ultraviolet (sunlight) exposure is the bone disease called rickets in children or osteomalacia in adults.
Source: ?

Vitamin D level
?
Source: ?

Vitamin D nutrition
?
Source: ?

Vitamin D receptor (VDR)
(1) proteins, usually found in the cytoplasm, that specifically bind 1,25(OH)2D, migrate to the nucleus, and regulate transcription of specific segments of DNA. A more correct term for VDR would be “calcitriol receptor”, but this not commonly used.
(2) a member of the superfamily of nuclear receptors for steroid hormones, thyroid hormone, and retinoic acid. The VDR functions as a 1,25 -activated transcription factor that ultimately influences the rate of RNA polymerase II-mediated transcription. VDRs are present not only in cells typically involved in calcium and bone metabolism, but also in other cell types, such as cells of the immune system.
Source: Mahtieu C and Adorini L, 2002

Vitamin D response element (VDRE)
a DNA sequence that is found in the promoter region of vitamin D regulated genes. Vitamin D receptor (receptor, calcitriol) binds to and regulates the activity of genes containing this element. A more correct term for VDRE would be “calcitriol response element”, but this not commonly used.
Source: ?

Vitamin D status
the measure of vitamin D nutritional status. The accepted measure of this is the concentration of serum 25-hydroxyvitamin D (25(OH)D).
Source: ?

Vitamin D toxicity
the toxicity associated with excessive intake of vitamin D. This is characterized by hypercalcaemia, i.e. dangerously raised blood calcium concentrations leading to dehydration, nausea, and deposition of calcium phosphate in soft tissues, vasculature and the kidney. In the severe form, without biochemical testing, this has been misdiagnosed as gastroenteritis. Excessive exposure to sunlight does not lead to excessive formation of vitamin D.
f&n,
Source: Reinhold Vieth

Back to top


W, X, Y, Z



Vitamin D compounds

9,10-seco(5Z,7E)-5,7,10(19)22-ergostatetraene-3b-ol

official name of vitamin D2

9,10-seco(5Z,7E)-5,7,10(19)cholestatriene-3b-ol

official name of vitamin D3


D3-25-hydroxylase


25(OH)D3


25(OH)D


25(OH)D3-1-hydroxylase


25(OH)D3-24-hydroxylase


24R,25(OH)2D3


1α,25(OH)2D3

(1) is considered to be a steroid hormone because the general mechanism by which it produces the biological responses attributed to vitamin D is similar to those of steroid hormones.
Source: Anthony W Norman

(2) plays an important multidisciplinary role in tissues not primarily related to mineral metabolism, e.g. the hematopoietic or blood system, effects on cell differentiation and proliferation including important interactions with keratinocytes and cancer cells, and participation in the processes of parathyroid hormone and insulin secretion.
Source: Anthony W Norman


1α,25(OH)2D3 analogs

chemically modified molecules derived from 1a,25(OH)2D3. Modifications have been made throughout the molecule, to obtain analogs with the desired properties. More than 1000 different vitamin D analogs have been synthesized worldwide.
Source: Mathieu C and Adorini L, 2002

Barbara M. van Amerongena, Reinhold Viethb and Anthony W. Normanc

aDepartment of Molecular Cell Biology and Immunology, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands.
bDepartment of Nutritional Sciences, and Department of Laboratory Medicine and Pathobiology, University of Toronto, Bone and Mineral Laboratory, Pathology and Laboratory Medicine, Mount Sinai Hospital, 600 University Ave, Toronto, Ont., Canada M5G 1X.
cDepartment of Biochemistry and Division of Biomedical Sciences, 5456 Boyce Hall, University of California, Riverside, CA 92521, United States.

We invite new definitions, feedback or comments on the definition

For new terms to be included, feedback or comment about definitions:

Reinhold Vieth or Barbara M van Amerongen