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Updated: Aug 18, 2026

Parallel Measurement of Circadian Clock Gene Expression and Hormone Secretion in Human Primary Cell Cultures
Published on: November 11, 2016
Diurnal rhythm in serum leptin
O D Wolthers1, C Heuck, C Skjaerbaek
1Department of Paediatrics, Randers Hospital, Denmark.
Aim:
To assess 24-hour serum leptin levels in children.
Subjects And Methods:
Five girls and two boys aged 10.4-13.6 (mean 12.2) years with pubertal stages I to III were studied. All children were healthy. A fasting blood sample was drawn at 08.00 hours, and thereafter samples were obtained every 2 hours throughout 24 hours until 08.00 hours the next morning. Serum leptin was measured by a specific radioimmunoassay.
Results:
A statistically significant circadian variation was found in mean leptin profile expressed as a percentage of overall day mean (F-ratio =10.4; P<0.001) with trough and peak levels (+/- SEM) at 10.00 (6.55+/-1.52 mg/l) and 24.00 hours (10.99+/-2.34 mg/l), respectively.
Conclusions:
In normal children serum leptin levels exhibit a nocturnal increase and a decrease during the morning. The nocturnal rise may represent a time lagged stimulating effect of insulin. The diurnal rhythm needs to be considered when serum leptin is assessed in clinical studies.
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