Casale R, Pasqualetti P
Department of Internal Medicine and Public Health, School of Medicine and Surgery, University of L'Aquila, Italy.
Panminerva Med. 1997 Sep;39(3):183-5.
Since erythropoietin (Epo) presents a diurnal rhythm in its circulating serum levels and it is reported increased in patients with chronic obstructive pulmonary disease (COPD), the circadian rhythm of Epo was investigated in a group of 40 normocytemic patients with chronic obstructive pulmonary disease compared with 40 clinically healthy subjects.
Venous blood samples were drawn in each subject during the span of a whole day every four hours, starting from midnight, for the determination of serum Epo levels by RIA. Statistical analysis was carried out by chronograms and by means of the "cosinor" method.
The control group presents a significant (p < 0.001) circadian rhythm in serum Epo levels, with maximum in the afternoon, whereas no rhythm (p > 0.05) is detected in the patient group. This has significantly (p < 0.05) higher mean daily levels and lower diurnal variations of serum Epo than the control group; a significant (p < 0.05) difference exists between the two groups regarding the peaks of rhythms.
These data confirm the presence of circadian rhythm in serum Epo levels and suggest that the COPD, by daytime hypoxemia with associated severe nocturnal desaturation, is associated with increased serum Epo levels both by day and by night, so that the physiological circadian rhythm is lost in these patients.
由于促红细胞生成素（Epo）的循环血清水平呈现昼夜节律，且据报道慢性阻塞性肺疾病（COPD）患者的促红细胞生成素水平升高，因此在一组40例正细胞性慢性阻塞性肺疾病患者中研究了促红细胞生成素的昼夜节律，并与40例临床健康受试者进行了比较。
从午夜开始，每4小时在每位受试者一整天的时间内采集静脉血样，通过放射免疫分析法测定血清促红细胞生成素水平。通过计时图和“余弦分析法”进行统计分析。
对照组血清促红细胞生成素水平呈现显著（p < 0.001）的昼夜节律，下午达到最高值，而患者组未检测到节律（p > 0.05）。与对照组相比，患者组血清促红细胞生成素的每日平均水平显著更高（p < 0.05），昼夜变化更低；两组在节律峰值方面存在显著（p < 0.05）差异。
这些数据证实了血清促红细胞生成素水平存在昼夜节律，并表明COPD患者由于白天低氧血症伴有严重的夜间去饱和，导致白天和夜间血清促红细胞生成素水平均升高，从而使这些患者失去了生理昼夜节律。
