Vitamin D Regulation
Vitamin D Regulation - Related Videos
01:30
Vitamins
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2024
Vitamins, derived from the Latin word for life, are essential organic substances required in small quantities for optimal growth and overall well-being. Unlike other organic nutrients, vitamins don't act as sources of energy or building materials but rather facilitate these nutrients' utilization by the body. Vitamins are predominantly coenzymes, assisting enzymes in specific chemical actions, like the oxidation of glucose for energy involving B vitamins. Most vitamins are not produced in our...
12:48
PLGA Nanoparticles Formed by Single- or Double-emulsion with Vitamin E-TPGS
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Cited by 211 •
2013
We describe the production and characterization of nanoparticles and microparticles composed of poly(lactic-co-glycolic acid) using vitamin E-TPGS as an emulsifier. By varying formulation parameters such as the concentration of emulsifier, it is possible to produce nanoparticles with mean diameters ranging from 220 nm to 1.98 µm.
01:46
Epigenetic Regulation
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2019
Epigenetic mechanisms play an essential role in healthy development. Conversely, precisely regulated epigenetic mechanisms are disrupted in diseases like cancer. In most mammals, females have two X chromosomes (XX) while males have an X and a Y chromosome (XY). The X chromosome contains significantly more genes than the Y chromosome. Therefore, to prevent an excess of X chromosome-linked gene expression in females, one of the two X chromosomes is randomly silenced during early development.
02:14
GTPases and their Regulation
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2020
Guanine nucleotide-binding proteins (G-proteins), also known as GTPases, are a superfamily of proteins that regulate many cellular processes, such as cell signaling, vesicular transport, and the regulation of cell shape and motility. Mutation or dysfunction of these proteins can lead to disease. There are around 40,000 known G-proteins that can broadly be classified into two groups ‒ small G-proteins consisting of a single domain and large multi-domain G-proteins. Large G-proteins, also known...
01:23
Role of Skin in Vitamin D Synthesis
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2023
The skin plays a crucial role in the synthesis of vitamin D, a vital nutrient for various physiological processes in the body. Vitamin D is unique because it can be synthesized in the skin through a series of chemical reactions triggered by exposure to ultraviolet B (UVB) radiation from sunlight. The solar UV B rays (290-315 nm) are absorbed by the skin, and 7-dehydrocholesterol (provitamin D3) photolyzes it to previtamin D3, which undergoes a rapid transformation to vitamin D3(cholecalciferol).
FAQs
A fall in blood calcium increases parathyroid hormone signaling, which stimulates the kidneys to produce more 1,25-dihydroxyvitamin D, or calcitriol. This active form supports the regulatory response that helps maintain calcium and phosphate balance. Once calcium becomes adequate, feedback from calcitriol and mineral levels reduces further activation, preventing the pathway from continuing unchecked.
Calcitriol provides feedback that limits its own further production, while adequate calcium and phosphate reduce the signals promoting additional activation. These controls create a balancing system rather than a one-way increase in vitamin D activity. Such feedback is important because mineral availability must remain coordinated with vitamin D activity to support skeletal maintenance without disrupting overall mineral balance.
Vitamin D3 produced in the skin is a precursor that undergoes processing in the liver and kidneys. The kidney-derived form, calcitriol, is the biologically active form emphasized in mineral regulation. Distinguishing these forms helps explain why normal production of an earlier form does not necessarily ensure effective regulation if later activation is affected by kidney or parathyroid problems.
The pathway links vitamin D activity with calcium and phosphate balance, two mineral conditions required for skeletal health. Calcitriol production is adjusted according to signals such as blood calcium and the presence of adequate minerals. This coordination helps explain why disruptions in vitamin D regulation can have consequences for bone mineralization, even when the initial problem involves the kidneys, parathyroid glands, or nutrition.
Nutritional deficiency and supplementation can be understood by considering the entire regulatory pathway rather than vitamin D production alone. Skin synthesis, liver conversion, renal activation, and feedback control each influence the final active signal. This framework helps relate dietary or supplemental vitamin D to the biological processes that ultimately affect calcium and phosphate balance and skeletal health.
The kidneys perform the activation step that produces calcitriol, while the parathyroid glands provide hormonal signals that respond to falling blood calcium. Disease affecting either site can therefore disturb the coordination between vitamin D activity and mineral balance. Studying these relationships helps connect abnormalities in calcium metabolism with changes in skeletal health and with the regulation of vitamin D.