Circadian rhythmic variations in serum concentrations of clinically important lipids.
Twenty-five apparently healthy adults (13 men and 12 women), mean age 29.5 years (SD 3.6 years), served as subjects in a 24-h study conducted in Barcelona (Spain) in spring of 1990. Six blood samples were collected from each subject at 4-h intervals over a 24-h period, beginning at 1000. The oral temperature was measured at 2-h intervals to facilitate an independent biological time reference. The serum concentrations of apolipoprotein (apo) A-I, apo B, cholesterol, high- and low-density lipoprotein cholesterol, and triglyceride were measured. The circadian rhythms of these quantities were studied with use of a periodic function resulting from the sum of two cosine functions of 24 and 12 h. For serum concentrations of apo A-I and apo B, only the 24- or 12-h components, respectively, were significant. However, the other quantities studied were significantly affected by both rhythmic components. The maximum daily rhythmic variation ranged from 5% (with respect to the daily mean) for apo A-I to 63% for triglyceride concentration. In all cases except triglyceride, the daily maximum values were measured in the afternoon samples, near the time of maximum oral temperature.
Rivera-Coll
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A
Servei de Bioquímica Clínica, Ciutat Sanitària i Universitària de Bellvitge, L'Hospitalet de Llobregat, Barcelona, Spain.
Fuentes-Arderiu
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X
Díez-Noguera
A
A
D000328:Adult; D016632:Apolipoprotein A-I / Q000378:metabolism; D001055:Apolipoproteins B / Q000378:metabolism; D002784:Cholesterol / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D008055:Lipids / Q000097:blood*; D008297:Male; D013030:Spain; D014280:Triglycerides / Q000097:blood
D016632:Apolipoprotein A-I; D001055:Apolipoproteins B; D008076:Cholesterol, HDL; D008055:Lipids; D014280:Triglycerides; D002784:Cholesterol