Faria A C, Veldhuis J D, Thorner M O, Vance M L
Department of Internal Medicine, University of Virginia Medical School, Charlottesville 22908.
J Clin Endocrinol Metab. 1989 Mar;68(3):535-41. doi: 10.1210/jcem-68-3-535.
The half-life (t1/2) of disappearance of endogenous GH from serum was studied using physiological effectors to stimulate and then suppress GH release. GH secretion was stimulated by a single iv injection of GHRH, followed 45 min later by an iv bolus dose and then a 2.5-h infusion of somatostatin (SRIH) to suppress further release. The in vivo t1/2 of GH in seven men was calculated from serum GH concentrations measured at frequent intervals after beginning the SRIH infusion. The mean t1/2 of endogenous GH was 18.9 +/- 0.8 (+/- SE) min by monoexponential analysis and 3.5 +/- 0.7 and 20.7 +/- 0.7 min by biexponential fitting. In these normal men, the decline in GH concentrations after GHRH and SRIH administration was similar to that after the administration of GHRH alone, which yielded a t1/2 of 20.3 +/- 1.9 min. We conclude that the physiological kinetics of endogenous GH removal/disappearance can be estimated in vivo in man using GHRH with or without SRIH infusion.
利用生理效应器刺激并随后抑制生长激素（GH）释放，研究了血清中内源性GH消失的半衰期（t1/2）。通过单次静脉注射生长激素释放激素（GHRH）刺激GH分泌，45分钟后静脉推注一剂，然后静脉输注2.5小时生长抑素（SRIH）以抑制进一步释放。在开始输注SRIH后，通过频繁测量血清GH浓度，计算出7名男性体内GH的t1/2。通过单指数分析，内源性GH的平均t1/2为18.9±0.8（±标准误）分钟，通过双指数拟合分别为3.5±0.7分钟和20.7±0.7分钟。在这些正常男性中，给予GHRH和SRIH后GH浓度的下降与单独给予GHRH后的下降相似，后者的t1/2为20.3±1.9分钟。我们得出结论，使用GHRH并输注或不输注SRIH，可在人体内对体内内源性GH清除/消失的生理动力学进行评估。
