Cremagnani L, Vaccari M, Maronati E, Cucchi L, Orsatti A, Lazzaroni L, Cantalamessa L
Istituto di Medicina Interna, Malattie Infettive e Immunopatologia, Università degli Studi di Milano, Italy.
Horm Metab Res. 1996 Feb;28(2):101-4. doi: 10.1055/s-2007-979137.
The aim of our study was to investigate the effect of galanin on basal and GHRH-stimulated GH secretion in a healthy group of elderly subjects and in a healthy group of young subjects for comparison. Ten old subjects (mean age 75 +/- 1.15 years) and an equal number of healthy young volunteers (mean age 26 +/- 0.71 years) underwent three stimulation tests in random order. Galanin infusion for 60 minutes (10 micrograms/kg in 100 ml saline) failed to provoke an appreciable release of circulating GH in old subjects, while it induced a significant increase of plasma GH in the young adults; GHRH administration i.v. in bolus (100 micrograms in 1 ml saline) elicited a significant GH response in both groups; however, in the older group GH response was significantly (p < 0.05) lower than in the young adults. The administration of galanin (10 micrograms/kg in 100 ml saline as an i.v. infusion for 60 min) plus GHRH (100 micrograms in 1 ml saline i.v. in bolus), potentiated GH response in old and young subjects. The combined administration of two peptides was able to elicit a clear GH release even in the older subjects who were hyporesponsive/unresponsive to galanin and/or GHRH alone. In the elderly, plasma GH values observed after the combined stimuli overlapped with GH values observed after GHRH alone in the young adults. In conclusion, our study confirms that galanin has a synergic effect with GHRH on GH release both in younger and elderly subjects. Moreover, our data confirm an impaired responsivity to GHRH in the elderly and demonstrate that galanin is able to normalize response of somatotrophs to GHRH in old people.
我们研究的目的是调查甘丙肽对健康老年组和健康青年组基础及生长激素释放激素（GHRH）刺激的生长激素（GH）分泌的影响，以便进行比较。10名老年受试者（平均年龄75±1.15岁）和同等数量的健康青年志愿者（平均年龄26±0.71岁）按随机顺序接受了三项刺激试验。对老年受试者静脉输注甘丙肽60分钟（100ml生理盐水中含10微克/千克）未能引起循环GH的明显释放，而在青年成年人中则诱导血浆GH显著增加；静脉推注GHRH（1ml生理盐水中含100微克）在两组中均引起显著的GH反应；然而，老年组的GH反应明显（p<0.05）低于青年成年人。静脉输注甘丙肽（100ml生理盐水中含10微克/千克，输注60分钟）加GHRH（1ml生理盐水中含100微克静脉推注）可增强老年和青年受试者的GH反应。两种肽联合给药即使在对甘丙肽和/或GHRH单独反应低下/无反应的老年受试者中也能引起明显的GH释放。在老年人中，联合刺激后观察到的血浆GH值与青年成年人单独使用GHRH后观察到的GH值重叠。总之，我们的研究证实甘丙肽在青年和老年受试者中对GH释放与GHRH具有协同作用。此外，我们的数据证实老年人对GHRH的反应性受损，并表明甘丙肽能够使老年人的生长激素细胞对GHRH的反应正常化。
