Corpas E, Blackman M R, Roberson R, Scholfield D, Harman S M
Gerontology Research Center, Baltimore, MD 21224.
J Gerontol. 1993 Jul;48(4):M128-33. doi: 10.1093/geronj/48.4.m128.
Older adults tend to have reduced growth hormone (GH) secretion and insulin-like growth factor I (IGF-I) levels as well as changes in body composition which are partially reversed by GH injections. Arginine stimulates GH release, and lysine may amplify this response. We investigated whether oral arginine/lysine could be used to increase basal IGF-I and GH levels in non-obese old men (age 69 +/- 5 years; mean +/- SD) to values similar to those of untreated young men (age 26 +/- 4 years).
Two groups of 8 healthy old men were treated with 3 g of arginine plus 3 g of lysine or with placebo capsules twice daily for 14 days. Before and on day 14 of each treatment GH levels were determined in blood samples taken at 20-minute intervals from 2000-0800 h, IGF-I was measured at 0800 h, and a 1 microgram/kg GHRH stimulation test was done.
At baseline, mean GH peak amplitude (p < .02) and serum IGF-I (p < .0001) were lower, whereas GHRH responses were similar, in old vs young men. Arginine/lysine did not significantly alter spontaneous or GHRH-stimulated GH levels, or serum IGF-I. Arginine absorption was age-independent. The correlation (p < .005) between measured increments in serum arginine and increases in serum GH after a single dose of arginine/lysine was similar in old and young groups.
Our data suggest that oral arginine/lysine is not a practical means of chronically enhancing GH secretion in old men.
老年人往往生长激素（GH）分泌减少、胰岛素样生长因子I（IGF-I）水平降低，且身体成分发生变化，而GH注射可部分逆转这些变化。精氨酸可刺激GH释放，赖氨酸可能会增强这种反应。我们研究了口服精氨酸/赖氨酸是否可用于提高非肥胖老年男性（年龄69±5岁；均值±标准差）的基础IGF-I和GH水平，使其达到与未治疗的年轻男性（年龄26±4岁）相似的值。
两组各8名健康老年男性，一组每天两次服用3克精氨酸加3克赖氨酸，另一组服用安慰剂胶囊，共治疗14天。在每次治疗前及治疗第14天，于20:00至08:00每隔20分钟采集血样测定GH水平，08:00测定IGF-I，并进行1微克/千克促生长激素释放激素（GHRH）刺激试验。
在基线时，老年男性与年轻男性相比，平均GH峰值幅度较低（p<0.02），血清IGF-I较低（p<0.0001），而GHRH反应相似。精氨酸/赖氨酸未显著改变自发或GHRH刺激的GH水平，也未改变血清IGF-I。精氨酸吸收与年龄无关。单剂量精氨酸/赖氨酸后，老年组和年轻组血清精氨酸测量增加值与血清GH增加值之间的相关性相似（p<0.005）。
我们的数据表明，口服精氨酸/赖氨酸并非长期增强老年男性GH分泌的实用方法。
