Pasqualetti P, Casale R
Department of Internal Medicine and Public Health, University of L'Aquila, School of Medicine and Surgery, Italy.
Gerontology. 1997;43(4):206-9. doi: 10.1159/000213851.
The diurnal rhythm in the circulating serum levels of erythropoietin (Epo) was investigated in a group of 20 clinically healthy subjects aged 30-55 years and in a group of 20 healthy subjects aged 55-75 years. Venous blood samples were drawn during the span of a whole day every 4 h, starting from midnight, for the determination of serum Epo levels by radioimmunoassay. Statistical analysis was carried out by means of the 'cosinor' method. Both groups presented a significant (p < 0.05) circadian rhythm in serum Epo levels, with maximum in the afternoon. The younger subjects had significantly (p < 0.05) higher mean daily levels and higher diurnal variations of serum Epo than older subjects; no difference (p > 0.05) was found between the groups regarding the peaks of the rhythms. These data confirm the presence of a circadian rhythm in serum EPO levels and suggest that the aging process does not influence the physiological diurnal fluctuations but modifies the mean daily levels and the amplitude of the diurnal variations, such as it occurs for many other variables. This behavior is an index of aging, but does not seem to have clinical implications.
在一组20名年龄在30至55岁的临床健康受试者以及一组20名年龄在55至75岁的健康受试者中，研究了循环血清中促红细胞生成素（Epo）水平的昼夜节律。从午夜开始，每隔4小时采集一次静脉血样，持续一整天，通过放射免疫分析法测定血清Epo水平。采用“余弦分析法”进行统计分析。两组受试者的血清Epo水平均呈现显著（p < 0.05）的昼夜节律，峰值出现在下午。较年轻的受试者血清Epo的平均每日水平显著（p < 0.05）高于年长受试者，且昼夜变化幅度更大；两组在节律峰值方面未发现差异（p > 0.05）。这些数据证实了血清EPO水平存在昼夜节律，并表明衰老过程并不影响生理昼夜波动，但会改变平均每日水平和昼夜变化幅度，许多其他变量也有类似情况。这种现象是衰老的一个指标，但似乎没有临床意义。
