The spelling of "calcitriol receptors" is determined by the International Phonetic Alphabet (IPA) phonetic transcription. "Calcitriol" is pronounced as /kælsiˈtraɪəl/ and "receptors" as /rɪˈsɛptərz/. The word "calcitriol" refers to a hormone that regulates calcium and phosphate levels in the body. The word "receptors" refers to the protein molecules that bind to specific substances, allowing cells to respond to external stimuli. Therefore, "calcitriol receptors" are the protein molecules that respond to calcitriol and regulate calcium and phosphate levels in the body.
Calcitriol receptors are proteins found in various cells throughout the body that bind with the hormone calcitriol, which is the active form of vitamin D. These receptors are part of the broader group of nuclear receptors, which are involved in regulating gene expression.
The primary function of calcitriol receptors is to mediate the biological effects of calcitriol by initiating a series of cellular responses. Once calcitriol binds to its receptor, it forms a complex that translocates into the cell nucleus. Within the nucleus, this complex interacts with specific DNA segments called vitamin D response elements (VDREs) located within the regulatory regions of target genes.
Binding of the calcitriol receptor to VDREs leads to the activation or repression of gene transcription. This, in turn, influences the synthesis of various proteins involved in calcium and phosphate homeostasis, cellular differentiation, proliferation, and immune function. Calcitriol receptors play a crucial role in maintaining normal bone health, as well as in regulating calcium absorption from the intestines and calcium resorption in the kidneys.
Dysregulation or malfunctioning of calcitriol receptors can lead to various disorders, such as vitamin D deficiency, skeletal deformities, and impaired immune responses. Pharmaceutical research targeting calcitriol receptors aims to develop drugs that can modulate their activity, potentially offering new therapeutic approaches for conditions like osteoporosis, kidney disease, and certain types of cancer.
The word "Calcitriol" is derived from the terms "calcium" and "triol". It is named as such because calcitriol is a hormonally active form of vitamin D that plays a critical role in regulating calcium homeostasis in the body.
The term "Receptors" comes from the Latin word "receptor", which means "receiver". In the context of biology, a receptor refers to a protein molecule that binds to specific substances, such as hormones or neurotransmitters, in order to initiate a physiological response.
Therefore, when combined, "Calcitriol Receptors" refers to the protein molecules in the body that specifically bind with calcitriol, enabling it to exert its effects on various cells and tissues.