Cholecalciferol , also known as vitamin D 3 and colecalciferol , is a type of vitamin D made by the skin, found in some food, and taken as a dietary supplement. It is used to treat and prevent vitamin D deficiency and related illnesses, including rickets. It is also used for familial hipofosfatemia, hypoparathyroidism that causes low blood calcium, and Fanconi syndrome. Usually drunk.
Excessive doses can cause vomiting, constipation, weakness, and confusion. Other risks include kidney stones. The normal dose is safe in pregnancy. May be ineffective in people with severe kidney disease.
Cholecalciferol is made in the skin after UVB exposure. It is converted into calcifediol (25-hydroxyvitamin D) by the liver and becomes calcitriol (1,25-dihydroxyvitamin D) by the kidney. One of the actions is to increase the absorption of calcium by the intestine. These are found in foods such as some fish, cheese, and eggs. Certain foods like milk contain cholecalciferol in some countries.
Cholecalciferol was first described in 1936. This is a List of Essential Medicines of the World Health Organization, the most effective and safe medicines needed in the health system. Cholecalciferol is available as a generic drug and on the table.
Video Cholecalciferol
Medical use
Vitamin D deficiency
Cholecalciferol is a form of vitamin D that is naturally synthesized in the skin and acts as a pro-hormone, which is converted into calcitriol. It's important to maintain calcium levels and improve bone health and development. As a drug, cholecalciferol may be taken as a dietary supplement to prevent or treat vitamin D deficiency. One gram is 40 million (40x10 6 ) IU, the equivalent of 1 IU is 0.025 Âμg. The value of dietary reference intake for vitamin D (cholecalciferol and/or ergocalciferol) has been established and recommendations vary depending on the country:
- In the US: 15Ã,Âμg/d (600 IU per day) for all individuals (men, women, pregnant/lactating women) between the ages of 1 and 70 years, inclusive. For all individuals older than 70 years, 20 Âμg/d (800 IU per day) is recommended.
- In the EU: 20Ã,Âμg/d (800 IU per day)
- In France: 25 Ã,Âμg/d (1000 IU per day)
Many questions as to whether the current recommended intake is sufficient to meet physiological needs. Individuals without sun exposure, obese individuals, and dark skin all have lower blood levels and require more supplementation.
The Institute of Medicine in 2010 recommended a maximum intake of vitamin D 4,000 IU/day, found that the lowest observed dose for the lowest observed effect was 40,000 IU daily for at least 12 weeks, and that there was one case of toxicity above 10,000 IU after more than 7 year daily intake; this toxicity case occurs in circumstances that have led other researchers to refute it as a credible case to consider when making recommendations for vitamin D intake. Patients with severe vitamin D deficiency will require treatment with loading doses; the magnitude can be calculated on the basis of serum 25-hydroxy-vitamin D levels and body weight.
There are conflicting reports about the relative effectiveness of cholecalciferol (D 3 ) versus ergocalciferol (D 2 ), with some studies showing less efficacy than D 2 , and others show no difference. There is a difference in the absorption, binding and inactivation of the two forms, with evidence typically supporting cholecalciferol in increasing blood levels, although more research is needed.
The use of cholecalciferol therapy is much less frequent in rickets using a large single dose and has been called stosion therapy. The treatment was administered orally or by intramuscular injection 300,000 IU (7,500 Âμg) to 500,000 IU (12,500 Âμg = 12.5 mg), in a single dose, or occasionally in two to four divided doses. There are concerns about the safety of such large doses.
Other diseases
A 2007 meta-analysis concluded that a daily intake of 1000 to 2000 IU per day of vitamin D3 can reduce the incidence of colorectal cancer with minimal risk. Also a 2008 study published in Cancer Research has demonstrated the addition of vitamin D 3 (along with calcium) to the diet of several mice given a similar regimen in nutritional content for a new Western diet with 1000 IU cholecalciferol per day prevent the development of colon cancer. In humans, with 400 IU daily, there is no effect of cholecalciferol supplementation on the risk of colorectal cancer.
Supplements are not recommended for cancer prevention because the cholecalciferol effect is very small. Although there is a significant correlation between low serum cholecalciferol blood levels and higher cancer rates, multiple sclerosis, tuberculosis, heart disease, and diabetes, the consensus is that supplementation rates are not favorable.
Maps Cholecalciferol
Biochemistry
Structure
Cholecalciferol is one of five forms of vitamin D. Cholecalciferol is a secosteroid, that is, a steroid molecule with one open ring.
Action mechanism
By itself cholecalciferol is inactive. This is converted into its active form by two hydroxylation: the first in the liver by CYP2R1 or CYP27A1 to form 25-hydroxycholecalciferol (calcifediol, 25-OH vitamin D 3 ), and the second in the kidneys by CYP27B1, to form 1,25-dihydrochlorcholecalciferol (calcitriol, 1,25- (OH) 2 vitamin D 3 ). All of these metabolites are bound in blood with vitamin D-binding proteins. Calcitriol action is mediated by vitamin D receptors, a nuclear receptor that regulates the synthesis of hundreds of enzymes and is present in almost every cell in the body.
Biosynthesis
Click the icon in the lower right corner to open it. Click on the genes, proteins and metabolites below to link to each article.
7-Dehydrocholesterol is a precursor of cholecalciferol. In the epidermal skin layer, 7-Dehydrocholesterol undergoes an electrocyclic reaction as a result of UVB rays at wavelengths between 290 and 315 nm, with synthesis peaks occurring between 295 and 300 nm. This results in the clearance of B-ring precursor vitamins through a conrotatory line that makes previtamin D3 (pre-cholecalciferol). In a process independent of UV rays, pre-cholecalciferol then undergoes [1,7] interfacial sfmatropic rearrangement and finally isomerization to form vitamin D 3 .
Active UVB wavelengths are present in the sun, and an adequate amount of cholecalciferol can be produced with moderate skin exposure, depending on the strength of the sun. Time, season, and altitude affect solar power, and pollution, cloud cover or glass all reduce the amount of UVB exposure. Exposure to face, arms and legs, an average of 5-30 minutes twice per week, may be enough, but the darker the skin, and the weaker the sunlight, the more minutes of exposure is required. Vitamin D overdose is not possible from UV exposure; the skin reaches a balance where the vitamin is degraded as soon as it is made.
Cholecalciferol can be produced in the skin from the light emitted by UV lamps in tanning beds, which produce ultraviolet mainly in the UVA spectrum, but usually produces 4% to 10% of total UV emissions as UVB. Higher levels of blood often use tanning salons.
Whether cholecalciferol and all vitamin D forms by definition "vitamins" is debatable, because the definition of vitamins includes that substances can not be synthesized by the body and must be digested. Cholecalciferol is synthesized by the body during exposure to UVB radiation.
Three steps in the synthesis and activation of vitamin D 3 are arranged as follows:
- Cholecalciferol is synthesized in the skin of 7-dehydrocholesterol under the action of ultraviolet B (UVB) rays. Achieving balance after several minutes depends on the intensity of UVB in the sun - determined by latitude, season, cloud cover, and altitude - as well as the age and degree of skin pigmentation.
- The hydroxylation of the hepatic endoplasmic reticulum of cholecalciferol hepatocytes to calcifediol (25-hydroxycholecalciferol) by 25-hydroxylase is loosely regulated, if at all, and the blood level of this molecule largely reflects the amount of cholecalciferol produced in the skin combined with each vitamin D < sub> 2 or D 3 digested.
- Hydroxylation in the calcifediol kidney for calcitriol by 1-alpha-hydroxylase is strictly regulated: it is stimulated by parathyroid hormone and serves as the main control point in the active production of circulating hormone calcitriol (1,25-dihydroxyvitamin D) 3 ).
Industrial production
Cholecalciferol is manufactured industrially for use in vitamin supplements and for fortifying foods. As a pharmaceutical drug called cholecalciferol (USAN) or colecalciferol (INN, BAN). This is produced by ultraviolet irradiation 7-dehydrocholesterol extracted from lanolin found in sheep wool. Cholesterol is extracted from wool fat and alcohol with wool wax obtained from cleaning wool after shaving. Cholesterol undergoes a four-step process to make 7-dehydrocholesterol, the same compound produced in animal skin. 7-dehydrocholesterol is then irradiated with ultraviolet light. Some unwanted isomers are formed during irradiation: these are removed by various techniques, leaving the resin melting at room temperature and typically have a potential of 25,000,000 to 30,000,000 International Units per gram.
Cholecalciferol is also manufactured industrially for use in vitamin supplements of moss, which is suitable for vegans.
Stability
Cholecalciferol is highly sensitive to UV radiation and will rapidly, but reversibly, break down to form a sterol-sura, which can then be irreversibly converted to ergosterol.
Use as rodenticide
Rodents are somewhat more susceptible to high doses than other species, and cholecalciferol has been used in poison feeds to control these pests. It has been claimed that the compound is less toxic to non-target species. However, in practice it has been found that the use of cholecalciferol in rodenticide is a significant danger to other animals, such as dogs and cats. Cholecalciferol produces hypercalcaemia, which produces soft-tissue systemic calcification, leading to renal failure, cardiac abnormalities, hypertension, CNS depression, and GI disorders.These signs generally develop within 18-36 hours of consumption and may include depression, anorexia, polyuria, and polydipsia. "
In New Zealand, possum has become a significant pest, and cholecalciferol has been used as an active ingredient in deadly gel feed and cereal pellet baits "DECAL" for possum control. LD 50 is 16.8 mg/kg, but only 9.8 mg/kg if calcium carbonate is added to the feed. Kidney and heart are target organs.
Cost
The cost of wholesale in Costa Rica is about 2.15 USD per bottle of 30 ml 10,000 IU/ml. In the United States maintenance costs are less than 25 USD per month. In the UK, a one-month maintenance fee for the NHS can be less than 3 GBP.
See also
- Hypervitaminosis D, Vitamin D Toxicity
- Ergocalciferol, vitamin D 2 .
- 25-Hydroxyvitamin D3 1-alpha-Hydroxylase, a kidney enzyme that converts calcifediol into calcitriol.
References
External links
- NIST Chemistry WebBook page for cholecalciferol
- Metabolism of vitamin D, sex hormones, and male reproductive function.
Source of the article : Wikipedia
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