Gc. Brainard et al., Influence of near-ultraviolet radiation on reproductive and immunological development in juvenile male Siberian hamsters, J EXP BIOL, 204(14), 2001, pp. 2535-2541
The aim of this study was to characterize the lenticular ultraviolet transm
ission of the Siberian hamster (Phodopus sungorus) and to probe the range o
f near-ultraviolet (UV-A, 315-400 nm) and visible wavelengths (400-760 nm)
for modulating the photoperiodic regulation of its reproductive and immune
systems. Ocular lenses from adult hamsters were found to transmit UV-A wave
lengths at similar levels to visible wavelengths, with a short-wavelength c
ut-off of 300 nn. Five separate studies compared the responses of juvenile
male hamsters to long photoperiods (16 h:8 h L:D), short photoperiods (10 h
:14 h L:D) and short photoperiods interrupted by an equal photon pulse of m
onochromatic light of 320, 340, 360, 500 or 725 nm during the night. The re
sults show that UV-A wavelengths at 320, 340 and 360 nm can regulate both r
eproductive and immune short-photoperiod responses as effectively as visibl
e monochromatic light at 500 nm. In contrast, long-wavelength visible light
at 725 nm did not block the short-photoperiod responses. These results sug
gest that both wavelengths in the visible spectrum, together with UV-A wave
lengths, contribute to hamster photoperiodism in natural habitats.