Vitamin D Synthesis
Vitamin D Synthesis - Related Videos
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).
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.
08:33
Hydrogel Synthesis
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2023
Source: Amber N. Barron, Ashlea Patterson, and Taylor D. Sparks, Department of Materials Science and Engineering, The University of Utah, Salt Lake City, UT Hydrogels are a versatile class of cross-linked polymers produced through relatively simple procedures and with generally inexpensive materials. They can be formed from solution and involve a polymer backbone formed from monomer reagents, an initiator which makes the polymer reactive and a crosslinking species which binds the polymer chains...
01:27
Mineral, Vitamin and Water Absorption
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2024
Electrolytes are essential minerals and ions primarily obtained from the diet and absorbed through the gastrointestinal tract. Most electrolytes are absorbed in the small intestine. While the absorption of iron and calcium primarily occurs in the duodenum, calcium is also absorbed in the jejunum and ileum. In these regions, passive diffusion contributes to its absorption alongside active transport mechanisms in the duodenum. These ions can exit the enterocytes through specialized active...
FAQs
Ultraviolet B radiation initiates the pathway by acting on 7-dehydrocholesterol in the skin. This reaction produces previtamin D3, which does not remain the final skin product; it undergoes a heat-driven rearrangement to vitamin D3. The sequence shows how an environmental input is converted into a biologically usable precursor for later metabolic processing.
The thermal rearrangement converts previtamin D3 into vitamin D3, creating the form that can proceed through the body’s organ-specific metabolic pathway. This step connects the initial ultraviolet reaction in skin with subsequent transformations elsewhere. Without distinguishing these intermediates, it would be difficult to track how the pathway progresses from environmental exposure toward hormone production.
The liver and kidneys perform different sequential hydroxylation steps rather than one organ completing the entire pathway. The liver produces 25-hydroxyvitamin D, while the kidneys carry out further hydroxylation to form calcitriol, the active hormone. This division of labor links vitamin D metabolism to organ-specific regulation and the control of calcium-related physiology.
Calcitriol represents the hormonally active endpoint of the pathway and connects vitamin D metabolism with calcium regulation. Because the pathway ends in an active hormone rather than merely a circulating precursor, changes in vitamin D processing can be studied in relation to skeletal health and broader mineral homeostasis. This endocrine connection gives the pathway physiological significance beyond skin metabolism.
A useful investigation follows the pathway across its major stages: ultraviolet B action on 7-dehydrocholesterol in skin, thermal formation of vitamin D3, liver production of 25-hydroxyvitamin D, and renal formation of calcitriol. Tracking these stages helps distinguish effects occurring during skin formation from those arising during later organ-specific metabolism or endocrine activation.
The pathway provides a framework for studying bone disorders, nutritional status, mineral homeostasis, and conditions associated with inadequate or excessive vitamin D activity. Its value comes from connecting sunlight exposure with measurable metabolic products and an active hormone. Researchers can therefore examine both environmental inputs and organ-level processing when investigating skeletal or calcium-regulation problems.