1. Estimating time to produce
vitamin D (1000 IU)
in the skin based on
atmospheric UV
PhD project, 2012
Janet Taylor
B.Sc, P.G Dip. Sci, M.Sc

2. Skin function and vitamin D receptors
B
A
Barrier formation
Innate immunity
Cell proliferation
A = vitamin D receptor interacting protein
B = steroid receptor complex
Epidermal keratinocytes differentiate to
form outer layer skin functions of
permeability barrier and immune
response
The calcitriol hormone-receptor complexes with the
receptor for 9-cis retinoic acid, then associates with either of
two co-activators depending on the stage of cell maturity
1,25(OH)2D (calcitriol) receptors also found on:
• trophoblasts, osteoblasts,
• macrophages, active T- and B-lymphocytes,
• pancreatic islet cells

3. Vitamin D (1,25(OH)2D
endocrine system
Low serum calcium High serum calcium
blocks calcium
mobilization
Ca2+-sensor in parathyroid gland
(coupled to a G-protein system)
C-cells in thyroid gland
Synthesis and secretion of PTH Secretion of calcitonin
• Increased renal 1α-hydroxylase
concentrations →
• Increased production of calcitriol
(1,25(OH)2D
Stimulates osteoblasts
Stimulates
osteoclastogenesis
Increased calcitriol stimulates:
• Intestinal absorption of calcium
• Mobilization of bone calcium
• Renal reabsorption of calcium

4. Recordings throughout the year
(av. 10 yr data ARPANSA)
19̊ S to 43̊ S – Townsville, Brisbane, Hobart
18
16
14
12
10
8
6
4
2
0
skin 2 A=10% Brisb
burn skin 2
12
10
8
6
4
0 10 20 30 40 50
UV Index
Vitamin D synthesis (1000 IU) (min)
12
10
8
6
4
2
0
0 50 100 150 200 250
UV Index
Vitamin D synthesis (1000 IU) (min)
skin 2 A=10% Hob
y = 58.961x-0.924 y = 166.68x-1
2
0 10 20 30 40 50
UV Index
min
skin 2
burn skin 2
Townsville 10am A=15%
Brisbane and Hobart, midday A=10%

5. Exponential relationship between UVI and
vitamin D synthesis (1000 IU) when A=10%
body surface exposed, all latitudes
18
16
14
12
10
8
6
4
2
0
410
380
350
320
290
260
230
200
28-Oct 5-Feb 15-May 23-Aug 1-Dec 11-Mar
Ozone (DU)
0 30 60 90 120 150 180 210 240
UV Index
Vitamin D synthesis (1000 IU) skin type 2, A=10% (min)
T'ville
Hob