Young J B, Rowe J W, Pallotta J A, Sparrow D, Landsberg L
Metabolism. 1980 Jun;29(6):532-9. doi: 10.1016/0026-0495(80)90078-5.
Plasma norepinephrine (NE) levels in response to upright posture and to oral glucose ingestion were measured in healthy young and old (greater than 65 yr of age) subjects. Peak plasma NE concentrations with standing were higher in the elderly (1334 +/- 146 pg/ml versus 855 +/- 46; p less than 0.05) and plasma NE remained elevated in the elderly compared with the young subjects even after 15 min of recumbent resting. Following oral glucose plasma NE rose higher in the elderly (79% compared with 32% in the young) and peaked later (120 min after ingestion compared with 60 min in the young). Cardiovascular changes with upright posture and with oral glucose were similar in young and old. Alterations in disappearance of NE from the circulation could not account for the greater elevations in plasma NE concentration in the elderly either, since the rates of fall in circulating NE levels following termination of an NE infusion were the same in both groups. The metabolic clearance rate of NE was unchanged. Thus, the plasma NE responses to stimulation by standing and by oral glucose ingestion are enhanced in elderly subjects.
在健康的年轻和老年（年龄大于65岁）受试者中，测量了对直立姿势和口服葡萄糖摄入的血浆去甲肾上腺素（NE）水平。站立时老年人血浆NE峰值浓度更高（分别为1334±146 pg/ml和855±46 pg/ml；p<0.05），并且即使在仰卧休息15分钟后，老年人血浆NE水平仍高于年轻受试者。口服葡萄糖后，老年人血浆NE升高幅度更大（与年轻人的32%相比为79%），且峰值出现时间更晚（摄入后120分钟，而年轻人为60分钟）。年轻和老年受试者在直立姿势和口服葡萄糖时的心血管变化相似。循环中NE消失的改变也不能解释老年人血浆NE浓度升高幅度更大的原因，因为在NE输注终止后，两组循环中NE水平的下降速率相同。NE的代谢清除率没有变化。因此，老年受试者对站立和口服葡萄糖摄入刺激的血浆NE反应增强。
