What is the Origin of UV Signal Transduction?

This term combines "UV," referring to the ultraviolet part of the light spectrum, with "signal transduction," the general biological mechanism of converting an external stimulus into an internal cellular response. The discovery of Vitamin D synthesis via sunlight provided the foundational understanding for this specific transduction pathway. It links environmental exposure directly to endocrine output.

What is the Mechanism of UV Signal Transduction?

UV-B photons penetrate the skin and are absorbed by 7-dehydrocholesterol, leading to a photochemical reaction that produces pre-vitamin D3. This molecule then isomerizes to Vitamin D3, which enters the circulation and is subsequently hydroxylated in the liver and kidney to its active hormonal form, calcitriol. The signal is transduced from light energy into a steroid hormone that modulates gene expression across numerous tissues.

UV Signal Transduction ∞ Area

UV Signal Transduction

Meaning

UV Signal Transduction is the biochemical process by which the energy from ultraviolet radiation, primarily UV-B, is absorbed by chromophores in the skin and converted into a systemic hormonal signal. The most clinically significant example is the conversion of 7-dehydrocholesterol to pre-vitamin D3, initiating the pathway for active Vitamin D synthesis. This transduction pathway is essential for bone health, immune function, and endocrine regulation.