Skin is an autonomous organ in synthesis, two-step activation and degradation of vitamin D3: CYP27 in epidermis completes the set of essential vitamin D3 …

M Schuessler, N Astecker, G Herzig, G Vorisek… - Steroids, 2001 - Elsevier
The current understanding of the vitamin D3 system shows skin as the unique site of vitamin
D3 production and liver is thought to be the main site of conversion to 25 (OH) D3. Skin is
capable of activating 25 (OH) D3 via 1α-hydroxylation and the resulting 1α, 25 (OH) 2D3
plays a role in epidermal homeostasis in normal and diseased skin. It also rapidly up-
regulates the major vitamin D3 metabolizing enzyme 24-hydroxylase at the mRNA level,
which is an established indicator for 1α, 25 (OH) 2D3-presence. We investigated the …