Sohmiya M, Kato Y
Department of Medicine, Shimane Medical University, Izumo, Japan.
J Clin Endocrinol Metab. 1992 Dec;75(6):1487-90. doi: 10.1210/jcem.75.6.1464653.
We studied the renal clearance, MCR, and half-life of the synthetic 22K form of human GH [recombinant hGH (rhGH)] in seven healthy young and five aged men by means of the constant iv infusion technique. rhGH was infused at a rate of 2 micrograms/kg.2 mL/h for 150 min, after which its disappearance was followed for 50 min. Changes in GH levels in plasma and urine were measured by a highly sensitive enzyme immunoassay. The mean (+/- SD) renal clearance of GH was significantly greater in the aged group than in the young group (14.3 +/- 2.5 vs. 4.2 +/- 1.0 microL/min; P < 0.05). The mean MCR was greater in the young group than in the aged group (187.1 +/- 43.7 vs. 120.5 +/- 39.5 mL/min; P < 0.05), but the MCR adjusted for body weight was not different between the two groups (2.9 +/- 0.6 vs. 2.3 +/- 0.8 mL/min.kg). No difference was noted in the half-life of GH between the two groups (13.8 +/- 0.9 vs. 14.2 +/- 0.4 min). These findings indicate that GH reabsorption from the renal tubule may be impaired in elderly subjects, but the disappearance rate of GH is not influenced by age.
我们采用持续静脉输注技术，研究了合成的22K形式的人生长激素[重组人生长激素（rhGH）]在7名健康年轻人和5名老年人中的肾脏清除率、代谢清除率（MCR）和半衰期。以2微克/千克·2毫升/小时的速率输注rhGH 150分钟，之后追踪其消失情况50分钟。采用高灵敏度酶免疫测定法测量血浆和尿液中生长激素水平的变化。老年人组生长激素的平均（±标准差）肾脏清除率显著高于年轻人组（14.3±2.5对4.2±1.0微升/分钟；P<0.05）。年轻人组的平均MCR高于老年人组（187.1±43.7对120.5±39.5毫升/分钟；P<0.05），但两组经体重校正后的MCR无差异（2.9±0.6对2.3±0.8毫升/分钟·千克）。两组间生长激素的半衰期无差异（13.8±0.9对14.2±0.4分钟）。这些发现表明，老年受试者肾小管对生长激素的重吸收可能受损，但生长激素的消失率不受年龄影响。
