Circadian and circannual rhythms of melatonin in plasma of male white‐tailed deer and the effect of oral administration of melatonin
作者:
G. A. Bubenik,
P. S. Smith,
期刊:
Journal of Experimental Zoology
(WILEY Available online 1987)
卷期:
Volume 241,
issue 1
页码: 81-89
ISSN:0022-104X
年代: 1987
DOI:10.1002/jez.1402410110
出版商: Wiley Subscription Services, Inc., A Wiley Company
数据来源: WILEY
摘要:
AbstractCircadian levels of melatonin (M) were determined in plasma of four male white‐tailed deer sampled hourly in September for 24 h via indwelling jugular catheter. Concentrations of M, detected by the radioimmunoassay rise with the onset of darkness, peak at 1.00 h (265 pg/ml) and then quickly decline to baseline levels (60 to 70 pg/ml) maintained during the scotophase. Orally administered M (5 mg, given at 13:00 h) induced a rapid elevation of plasma M (peak 980 pg/ml at 15:00 h) followed by a decline to baseline (100 pg/ml) reached at 22:00 h. The usual midscotophase peak was abolished by exogenous M administration. Seasonal midscotophase levels of M (determined in three samples taken 45 min apart between 23:00 and 1:00 h reach maximum in December (1530 pg/ml) followed by decline to minimum (69 to 90 pg/ml) observed between May and July. The data indicate that: 1) similarly to other mammals, deer exhibit peak level of M during the dark phase; 2) 5 mg of M given orally caused a rapid elevation of M levels in blood followed by a depression of the normally present night‐time peak; and 3) midscotophase levels of M exhibit very pronounced seasonal fluctuations which might be related to yearly cycles, such as the reproduction, hair molt, and antler gro
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