Department of Paediatrics, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
University Health Care Research Centre, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
Horm Res Paediatr. 2022;95(5):442-451. doi: 10.1159/000526147. Epub 2022 Jul 27.
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.
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 μg/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.
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).
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.
生长激素释放激素（Ghrelin）在青春期时的浓度下降，但其机制尚不清楚。酰化 Ghrelin（AG）在采样管中不稳定，但目前尚无标准化的采样方案。我们假设 Ghrelin 水平的降低是由于促性腺激素释放激素（GnRH）信号增加所致，并且向采样管中添加蛋白酶抑制剂可以保持 AG 水平。
在这项随机、安慰剂对照、交叉研究中，纳入了 13 名疑似中枢性性早熟的女孩。她们两次进行了调整后的 GnRH 刺激试验，并随机接受了 Relefact LHRH®（100μg/m2）或生理盐水注射。在 150 分钟内反复采血，以分析激素浓度。仅在基线时测量雌二醇水平。在采样管中添加了蛋白酶抑制剂 4-（2-氨基乙基）苯磺酰氟盐酸盐（AEBSF）。使用特异性 ELISA 试剂盒分析 AG 和去酰化 Ghrelin（DAG）水平。
与生理盐水相比，GnRH 类似物注射后 AG 和 DAG 水平均无变化。添加 AEBSF 可保持 AG 水平（650.1±257.1 vs. 247.6±123.4 pg/mL，p<0.001），并降低 DAG 水平（51.9[12.5-115.7] vs. 143.5[71.4-285.7] pg/mL，p<0.001）。AG 和 DAG 水平均与胰岛素水平呈负相关（r=-0.73，p=0.005，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）。
短期内，女孩接受 GnRH 类似物药物剂量注射后，Ghrelin 水平不会下降。向采样管中添加蛋白酶抑制剂可减少 AG 降解，从而保持 AG 水平，降低 DAG 水平。
