The vitamin D receptors in the body bind to hormones and DNA proteins to affect gene expression and vitamin D synthesis. The receptors, also called calcitriol receptors, aid in vitamin D absorption and production within the body. They help regulate vitamin D within the body and are present in various places, including the liver and skin. Some studies suggest that an alteration in vitamin D receptors may increase the risk for breast and other cancers, as proper vitamin D absorption is a necessary component for preventing certain forms of cancer and other diseases.
When vitamin D is synthesized from the precursor cholesterol, found within our skin, it binds with intracellular receptors called calcitriol receptors. These receptors regulate the action of vitamin D in our bodies and contain hormone and DNA binding sites. Most studies suggest that the role of vitamin D receptors, or VDR, is to activate transcription, or the making of a gene. Most of the time, VDR form a network with the retinoid-X receptor which aids in the binding of DNA, and is said to be homologous, or the same shape as other surrounding nuclear receptors.
Vitamin D is an important vitamin which aids in the absorption of calcium and has been shown to decrease certain symptoms of depression. When vitamin D receptors are inactive or are not functioning properly, which happens occasionally in some individuals, many of the benefits to vitamin D intake become obsolete. The problems with vitamin D receptors usually occur in the genetic sequence of DNA which codes for the receptor, and may increase rickets in children or osteoporosis in older adults due to inadequate calcium absorption. Also, since vitamin D aids in preventing certain infections and cancer by increasing the immune system, trouble with vitamin D receptors may cause an increase in breast and other cancers.
One study shows that specific sequences of the vitamin D receptor gene may increase the risk of breast or prostate cancer in different individuals. African American men, for example, carried a higher risk for developing prostate cancer due to the sequence of DNA and regulatory proteins associated with vitamin D receptors. Other studies show that proper functioning receptors aid in fighting and obliterating infections and bacteria, such as salmonella. When bacteria is presented to the body, vitamin D receptors are able to bind to the bacteria and decrease its function by regulating certain bacteria development pathways.