Diurnal variations in hyaluronan (HA) content in serum are described, however these changes are believed lo exist due to morning activity or physical exercise. Our study was designed to determine if 1) circadian rhythm in HA content exists without physical activity and in if 2) peaks in HA concentrations are due to food intake. Consequently we measured HA concentrations in plasma in a 30 min. interval in 4 test subjects during a one day bedrest period under standardized conditions, which represent either three times food intake per day or small meals distributed by 30 min. intervals during the whole experiment. HA was measured by a sensitive immunoassay developed in our lab, which is based on the affinity of proteoglycan to HA and possesses a sensitivity of 0.24μg/L. Meals three times a day led to elevations in HA concentration immediately after eating with a major peak at 9:30, which confirms other publications. In contrast continues feeding resulted in maintaining a constant daily HA level except a reproducible elevation after waking up. We conclude that circadian rhythms in HA mainly depend on food intake as well as physical activity. Without both stressors a circadian rhythm could only be detected in the early morning contradicting, previous publications.
|Publication status||Published - dec. 1 1997|
ASJC Scopus subject areas
- Molecular Biology