# THE PHOTOBIOLOGY OF VITAMIN D

> **NIH NIH R01** · BOSTON UNIVERSITY MEDICAL CAMPUS · 1988 · $44,342

## Abstract

We have now established many of the essential features of sun-mediated
cutaneous synthesis of vitamin D3.  During exposure to sunlight epidermal
7-dehydrocholesterol (7-DHC) is converted to previtamin D3 (preD3).  Once
formed previtamin D3 can either thermally isomerize to vitamin D3 or
photoisomerize to lumisterol and tachysterol.  Because the
vitamin-D-binding protein has selective affinity for vitamin D3 it is
thought that this protein plays a role in the translocation of vitamin D3
into the circulation.  We have developed the methodology to evaluate in
human subjects the effect of exposure to UV radiation on circulating levels
of vitamin D3 and its metabolites.  During the past 3 years we have
developed new technology including (1) high resolution high performance
liquid chromatography and gas-liquid chromatography methods to separate
7-DHC from other sterols and its photoproducts, (2) tissue culturing of
1,25-(OH)2-D receptor + and - keratinocytes and fibroblast, (3) synthesis
of radiolabeled photoproducts of preD3 and vitamin D3 and a light source
that mimics natural sunlight.  Using these techniques we plan to expand our
productive research program and investigate the (1) photoconversion of
preD3 and vitamin D3 in human skin to toxisterols and suprasterols and
their physiologic consequences, (2) translocation and metabolism of
lumisterol and tachysterol in human skin, (3) role of cutaneous
7-DHC-esters in the production of vitamin D3, (4) factors such as UV
radiation 7-DHC photoproducts and vitamin D metabolites that could regulate
cutaneous 7-DHC production, (5) changes in circulating concentrations of
vitamin D3 and its metabolites after exposure to UV radiation in health and
disease and (6) therapeutic effectiveness of using the skin as the site of
synthesis absorption of vitamin D metabolites.

## Key facts

- **NIH application ID:** 3157833
- **Project number:** 3R01AR036963-03S1
- **Recipient organization:** BOSTON UNIVERSITY MEDICAL CAMPUS
- **SAM.gov UEI:** FBYMGMHW4X95
- **Principal Investigator:** MICHAEL F. HOLICK
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1988
- **Award amount:** $44,342
- **Award type:** 3
- **Project period:** 1987-09-01 → 1988-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3157833

## Citation

> US National Institutes of Health, RePORTER application 3157833, THE PHOTOBIOLOGY OF VITAMIN D (3R01AR036963-03S1). Retrieved via MORVS 2026-10-24 from https://api.morvs.ai/grant/nih/3157833. Licensed CC0.

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