Roberts D, Smith D J
Faculty of Kinesiology, University of Calgary, Alberta, Canada.
J Appl Physiol (1985). 1996 Mar;80(3):847-51. doi: 10.1152/jappl.1996.80.3.847.
The hormone erythropoietin (Epo) produced in the kidneys in response to hypoxia stimulates the production of red blood cells. We measured serum Epo levels in 26 healthy men over a 24-h period to determine whether Epo is secreted according to a circadian rhythm. Samples were collected every 2-4 h, and Epo was measured by using a radioimmunoassay (INCSTAR Epo-trac). To determine whether blood collection had any effect on Epo production, one-half of the subjects began the collection period in the morning and the other half in the evening. Exercise and the use of prostaglandin inhibitors were prohibited to eliminate fluctuations in Epo production in response to discrete stimuli. The daily Epo concentration for all subjects combined was 15.5 +/- 5.3 (SD) U/l. No significant circadian variation in serum Epo concentrations was observed in either group or when both groups were combined; however, a measure of individual variance was observed (mean deviation = 0.8 +/- 0.4 U/l).
肾脏在低氧状态下产生的促红细胞生成素（Epo）可刺激红细胞生成。我们在24小时内对26名健康男性的血清Epo水平进行了测量，以确定Epo是否按照昼夜节律分泌。每2 - 4小时采集一次样本，采用放射免疫分析法（INCSTAR Epo - trac）测定Epo。为确定采血是否对Epo产生有任何影响，一半受试者在早晨开始采集期，另一半在晚上开始。禁止运动和使用前列腺素抑制剂，以消除因离散刺激导致的Epo产生波动。所有受试者的每日Epo浓度合并后为15.5±5.3（标准差）U/l。在任何一组或两组合并时，均未观察到血清Epo浓度有显著的昼夜变化；然而，观察到了个体差异的一种度量（平均偏差 = 0.8±0.4 U/l）。
