Daily rhythm of plasma insulin in Japanese quail (Coturnix c. japonica) fed ad libitum.
1. Plasma levels of immuno-reactive insulin (IRI) of 6 groups of 5-week-old quail, held on a 16L:8D photoregime, were measured every 4 hr, for 24 hr. 2. Concentrations of plasma IRI varied during the 24 hr period (Anova, P < 0.003). Insulin levels were high (mean = 857 pg/ml) from 6 a.m. (light onset) until 6 p.m. (4 hr before light offset) and low (mean = 185 pg/ml) at 10 p.m. and 2 a.m. 3. IRI concentrations at 6 a.m., 10 a.m., 2 p.m. and 6 p.m. were significantly different from values at 2 a.m. and 10 p.m. by Waller grouping. 4. Low IRI levels at light offset (10 p.m.--when the birds had full crops and were in an absorptive state) and high levels at light onset (6 a.m.--before feeding resumed) indicate that feeding does not fully account for the IRI rhythm.
Tedford
B L
BL
Department of Zoology and Physiology, Louisiana State University, Baton Rouge 70803.
Meier
A H
AH
D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology*; D003370:Coturnix / Q000097:blood*; D004040:Dietary Carbohydrates / Q000494:pharmacology; D004435:Eating / Q000502:physiology*; D007328:Insulin / Q000097:blood*; D011863:Radioimmunoassay
D004040:Dietary Carbohydrates; D007328:Insulin