Suri D, Hindmarsh P C, Brain C E, Pringle P J, Brook C G
Endocrine Unit, Middlesex Hospital, London, UK.
Clin Endocrinol (Oxf). 1990 Sep;33(3):399-406. doi: 10.1111/j.1365-2265.1990.tb00505.x.
Six normal adult males were given clonidine and GHRH either separately, or in combination, in random order. The peak serum GH concentrations elicited by clonidine or GHRH were variable but one factor influencing the GH response to GHRH was the GH secretory status in the hour prior to the administration of the GHRH. Peak serum GH concentrations attained were significantly greater when serum GH concentrations were rising (mean 52.9 mU/l, SD 17.2) than if they were falling (mean 27.5 mU/l, SD 13.3) or unchanged/undetectable (mean 20.6 mU/l, SD 9.8) (one-way ANOVA, F = 8.77; P = 0.004). The GH response to clonidine was not influenced by the secretory status in the hour prior to administration of clonidine. Pretreatment with clonidine did not augment the peak serum GH response to GHRH but the direction of response was more predictable than when GHRH was administered separately or repeatedly. Prior treatment with GHRH(1-29)-NH2 led to a marked attenuation of the peak serum GH response to clonidine. These results suggest that the alpha-2 adrenergic agonists probably stimulate GH secretion through pathways other than just GHRH.
六名正常成年男性按随机顺序分别单独或联合给予可乐定和生长激素释放激素（GHRH）。可乐定或GHRH引起的血清生长激素（GH）峰值浓度各不相同，但影响GH对GHRH反应的一个因素是在给予GHRH前一小时的GH分泌状态。当血清GH浓度上升时（平均52.9 mU/l，标准差17.2），达到的血清GH峰值浓度显著高于其下降时（平均27.5 mU/l，标准差13.3）或未改变/未检测到时（平均20.6 mU/l，标准差9.8）（单因素方差分析，F = 8.77；P = 0.004）。GH对可乐定的反应不受给予可乐定前一小时分泌状态的影响。可乐定预处理并未增强血清GH对GHRH的峰值反应，但反应方向比单独或重复给予GHRH时更可预测。预先用GHRH(1-29)-NH2治疗导致血清GH对可乐定的峰值反应明显减弱。这些结果表明，α2肾上腺素能激动剂可能通过不仅仅是GHRH的途径刺激GH分泌。
