Table 1. Serum and tissue content of mono-hydroxy D3 metabolites.

Secosteroid	Epidermis (ng/mgprotein)	Serum (ng/ml)
20(OH)D3	0.40 ± 0.15	1.15 ± 0.20
22(OH)D3	ND*	2.38 ± 0.65
25(OH)D3	0.06 ± 0.02	33.58 ± 5.36
D3	0.13 ± 0.05	2.39 ± 0.34

^*ND, not done because the 22(OH)D3 signal is buried in the contaminating peaks.