Related Experiment Video
Updated: Aug 11, 2026
Light/dark Transition Test for Mice
Published on: November 13, 2006
The influence of light and darkness on cutaneous fluorescence in mice
Petras Juzenas1, Asta Juzeniene, Vladimir Iani
1Department of Radiation Biology, The Norwegian Radium Hospital, N-310 Oslo, Norway. petras.juzenas@labmed.uio.no
Abstract:
The present work was carried out to investigate the role of light and darkness on the endogenous biosynthesis of porphyrins in mammalian skin (hairless BALB/c mouse) in vivo. In the skin of mice that were constantly kept in darkness (DD), increased endogenous porphyrin fluorescence was observed, which mainly originated from protoporphyrin IX (PpIX). No significant increase in the porphyrin levels was observed in mice that were kept under a normal day-night cycle (LD 12:12 h). The presence of cutaneous PpIX together with ambient light may comprise a photosensitizing mechanism by which PpIX may be a photomessenger between ambient light and internal rhythms.
