Introduction: Ghrelin concentrations decline during puberty by an unclear mechanism. Acylated ghrelin (AG) is unstable in sampling tubes, but no standardized sampling protocol exists. We hypothesized that ghrelin levels decrease as a consequence of increased gonadotropin releasing hormone (GnRH) signalling and that the addition of a protease inhibitor to sampling tubes preserves the AG levels. Methods: In this randomized, placebo-controlled, cross-over study, 13 girls with suspected central precocious puberty were included. They performed an adjusted GnRH stimulation test twice and were given Relefact LHRH® (100 g/m2) or saline in a randomized order. Blood was sampled repeatedly for 150 min for the analysis of hormone concentrations. Oestradiol levels were only measured at baseline. The protease inhibitor 4-(2-aminoethyl) benzenesulfonyl fluoride hydrochloride (AEBSF) was added to the sampling tubes. Specific ELISA kits were used for the analysis of AG and desacylated ghrelin (DAG) levels. Results: Neither AG nor DAG levels changed after GnRH analogue injection in comparison to saline. The addition of AEBSF preserved AG levels (650.1  257.1 vs. 247.6  123.4 pg/ml, p<0.001) and decreased DAG levels (51.9 (12.5–115.7) vs. 143.5 (71.4–285.7) pg/ml, p<0.001). Both AG and DAG levels were inversely associated with insulin levels (r=-0.73, p=0.005, and r=-0.78, p=0.002, respectively). AG levels were inversely associated with oestradiol levels (rho=-0.57, p=0.041). Conclusion: Ghrelin levels do not decrease following a pharmacological dose of a GnRH analogue in the short term in girls. Addition of a protease inhibitor to the sampling tubes decreases AG degradation, resulting in preserved AG and decreased DAG levels.


中文翻译：

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GnRH 类似物注射对女孩生长素释放肽水平影响的随机试验

简介：Ghrelin 浓度在青春期下降，机制不明。酰化生长素释放肽 (AG) 在采样管中不稳定，但不存在标准化的采样协议。我们假设由于促性腺激素释放激素 (GnRH) 信号增加而导致生长素释放肽水平降低，并且在采样管中添加蛋白酶抑制剂可保持 AG 水平。方法：在这项随机、安慰剂对照、交叉研究中，包括了 13 名疑似中枢性性早熟的女孩。他们进行了两次调整后的 GnRH 刺激试验，并以随机顺序给予 Relefact LHRH® (100 μg/m2) 或生理盐水。血液被重复取样 150 分钟以分析激素浓度。雌二醇水平仅在基线时测量。将蛋白酶抑制剂 4-(2-氨基乙基) 苯磺酰氟盐酸盐 (AEBSF) 添加到采样管中。特定的 ELISA 试剂盒用于分析 AG 和脱酰化生长素释放肽 (DAG) 水平。结果：与生理盐水相比，GnRH 类似物注射后 AG 和 DAG 水平均未发生变化。添加 AEBSF 可保持 AG 水平（650.1 ± 257.1 对比 247.6 ± 123.4 pg/ml，p<0.001）并降低 DAG 水平（51.9 (12.5–115.7) 对比 143.5 (71.4–285.7) pg/ml，p<0.001 ). AG 和 DAG 水平均与胰岛素水平负相关（分别为 r=-0.73，p=0.005 和 r=-0.78，p=0.002）。AG 水平与雌二醇水平呈负相关 (rho=-0.57, p=0.041)。结论：在短期内，女孩 GnRH 类似物的药理学剂量不会降低 Ghrelin 水平。