Suppression of melatonin secretion in Ile-de-France rams by different light intensities.
The intensity of cool, white, fluorescent light required to suppress melatonin secretion in Ile-de-France rams was investigated. Animals were conditioned to 12L:12D, lights on 0600 hours, 104 microW/cm2 (350 lux) at eye level and subjected to a 1-hour light pulse beginning 3 hours after lights off. Plasma melatonin measurements indicated that secretion was significantly suppressed by 0.30, 7.46, and 26.32 microW/cm2 (1.02, 25.10, and 88.60 lux, respectively) but not by 0.043 microW/cm2 (0.15 lux). A clear dose-response relationship was apparent between light intensity and degree of melatonin suppression.
Arendt
J
J
Department of Biochemistry, University of Surrey, Guildford, England.
Ravault
J P
JP
D000818:Animals; D008027:Light; D008297:Male; D008550:Melatonin / Q000037:antagonists & inhibitors* / Q000097:blood / Q000378:metabolism; D012756:Sheep / Q000378:metabolism*
D008550:Melatonin