Medicus, Vol. 24 No. 2 ASK niske doze, 2015.
Pregledni rad
Alphacalcidol
Luka Bielen
Iva Žagar
Sažetak
Vitamin D belongs to a group of fat-soluble compounds whose basic structure includes four cholesterol rings. Since very few foods naturally contain vitamin D, this compound in the human body mostly comes from the endogenous synthesis in dermis under the influence of ultraviolet radiation. Vitamin D from the synthesis in dermis and that from the diet are biologically inactive compounds and are activated in the liver and kidneys by hydroxylation. Normal vitamin D level is of paramount importance for bone metabolism and for calcium and phosphate homeostasis. Moreover, the gene for vitamin D receptor is ubiquitary expressed in living cells and about 3% of human genome is under the control of vitamin D, explaining many of its extraskeletal effects, such as those on skeletal muscles, immune system, cardiovascular system and the development of malignant diseases and diabetes. Vitamin D level is estimated by measuring serum concentration of calcidiol, the main circulating form of vitamin D. According to recent studies, the prevalence of vitamin D deficiency is high and in some areas exceeds 50%. Risk factors include first year of life, older age, fat malabsorption, impaired liver and kidney function, low level of sun exposure, wearing clothes covering most of the body, etc. Vitamin D replenishment can be achieved with different forms of vitamin D and its analogues, including alphacalcidol. Alphacalcidol is 1-alpha-hydroxycholecalciferol, the form of vitamin D that is activated in the liver, bypassing hydroxylation in the kidneys. It is characterized by rapid onset of action, while the absence of hydroxylation in the kidney represents a favourable characteristic for patients with impaired kidney function and those on maintenance haemodialysis.
Ključne riječi
vitamin D physiology; vitamin D effects; vitamin D deficiency; alphacalcidol
Hrčak ID:
148325
URI
Datum izdavanja:
4.11.2015.
Posjeta: 3.315 *