Influence of near-ultraviolet radiation on reproductive and immunological development in juvenile male Siberian hamsters

• Published in: Journal of experimental biology Vol. 204; no. Pt 14; pp. 2535 - 2541
• Main Authors: Brainard, G C, Hanifin, J P, Barker, F M, Sanford, B, Stetson, M H
• Format: Journal Article
• Language: English
• Published: England 01.07.2001
• Subjects: Animals; Cricetinae; Cricetulus; Genitalia, Male - growth & development; Male; Mesocricetus; Reproduction - physiology; Spectroscopy, Near-Infrared
• ISSN: 0022-0949; 1477-9145
• DOI: 10.1242/jeb.204.14.2535

The aim of this study was to characterize the lenticular ultraviolet transmission of the Siberian hamster (Phodopus sungorus) and to probe the range of 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 wavelengths at similar levels to visible wavelengths, with a short-wavelength cut-off of 300 nm. 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 monochromatic light of 320, 340, 360, 500 or 725 nm during the night. The results show that UV-A wavelengths at 320, 340 and 360 nm can regulate both reproductive and immune short-photoperiod responses as effectively as visible monochromatic light at 500 nm. In contrast, long-wavelength visible light at 725 nm did not block the short-photoperiod responses. These results suggest that both wavelengths in the visible spectrum, together with UV-A wavelengths, contribute to hamster photoperiodism in natural habitats.