Aging affects development and persistence of feeding-associated circadian rhythm in rat plasma corticosterone.
Effects of aging on development and persistence of feeding-associated circadian rhythm were examined with respect to the prefeeding plasma corticosterone peak under restricted feeding. Old (20 mo), middle-aged (12 mo), and young (2.5 mo) male rats were subjected to a restricted feeding schedule for 21 days in which free access to food was limited to 2 h/day in the light phase. Prefeeding corticosterone peak was detected 1 wk after the start of the schedule in the young and 3 wk after in the old and middle-aged rats. After the restricted feeding, a feeding/ fasting cycle composed of 7 days of ad libitum feeding and 3 days of fasting was imposed four times. The persistence of feeding-associated rhythm was evaluated by examining the reappearance of the corticosterone peak at the previous meal time during each fasting period of the feeding/fasting cycle. The corticosterone peak was not detected in the old and middle-aged rats even at the first cycle, but it was still distinct at the third cycle in the young rats. In conclusion, aging impaired the development and persistence of feeding-associated circadian rhythm in rats.
Honma
S
S
Department of Physiology, Hokkaido University School of Medicine, Sapporo, Japan.
Katsuno
Y
Y
Abe
H
H
Honma
K
K
D000375:Aging / Q000502:physiology*; D000818:Animals; D001835:Body Weight; D002940:Circadian Rhythm; D003345:Corticosterone / Q000097:blood*; D004435:Eating; D005247:Feeding Behavior / Q000502:physiology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012149:Restraint, Physical; D013312:Stress, Physiological / Q000097:blood / Q000209:etiology
D003345:Corticosterone