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.
For new terms to be included, feedback or comment about definitions:
Reinhold Vieth or Barbara M van Amerongen
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
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.
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
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
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
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
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
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
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
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
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
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
Ligand
any molecule that binds to a specific site on a protein or
other molecule.
Source: ?
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
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
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
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
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
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
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
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
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
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)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