Light affects neonatal rat pineal gland N-acetyltransferase activity by an extra-retinal mechanism.
To determine whether extra-retinal mechanisms mediate photoperiodic changes in neonatal rat pineal gland N-acetyltransferase activity, 4-day-old intact or bilateral orbital enucleated rats were killed during the dark phase of the lighting cycle, either in darkness or following 4 hr exposure to fluorescent light. Light suppressed the high nighttime N-acetyltransferase activity equally in intact and enucleated pups. Subsequent studies showed that at least 0.5 hr exposure and nocturnal illuminances of 109 microW/cm2 or greater were required to cause statistically significant reductions in the activity of the enzyme in 4-day-old rats. Taken together, these data indicate that relatively intense environmental light can affect neonatal rat pineal gland biochemistry via extraretinal mechanisms.
Torres
G
G
Department of Psychology, University of California, Santa Barbara.
Lytle
L D
LD
D000123:Acetyltransferases / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism* / Q000502:physiology; D001191:Arylamine N-Acetyltransferase / Q000378:metabolism*; D002940:Circadian Rhythm; D005260:Female; D008029:Lighting; D008297:Male; D010870:Pineal Gland / Q000201:enzymology* / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains
D000123:Acetyltransferases; D001191:Arylamine N-Acetyltransferase