Characterization of ghrelin-like immunoreactivity in human plasma
Characterization of ghrelin-like immunoreactivity in human plasma
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DOI：
10.1210/jc.2004-1641
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发表时间：
2005-04-01
影响因子：
5.8
通讯作者：
Bloom, SR
中科院分区：
文献类型：
--
作者：
Patterson, M;Murphy, KG;Bloom, SR
生长素释放肽是一种胃肽激素，在食欲控制和生长激素释放方面具有重要作用。循环中的生长素释放肽水平与体重指数成反比，并在餐后受到抑制。然而，循环胃饥饿素的分子形式尚未完全表征。我们使用三种 RIA 研究了循环生长素释放肽样免疫反应性 (Ghr-LI)：一种仅针对活性、酰化生长素释放肽（抗体 G0-1），另外两种检测活性和非活性、去酰化生长素释放肽（抗体 SC 和市售的 Phoenix Pharmaceuticals 检测）。在测试早餐后测量健康受试者的血浆生长素释放肽水平（n = 8）。 SC 和商业检测检测到的 Ghr-LI 在餐后 90 和 120 分钟显着下降（P < 0.01）。 G0-1 Ghr-LI 在餐后 30 分钟显着下降（P < 0.05），并在 90 分钟恢复到基础水平。凝胶渗透色谱法鉴定出血浆中的三个 Ghr-LI 峰。检测到两个分子量远大于ghrelin肽的G0-1 Ghr-LI峰。 SC 和商业 RIA 仅检测到一个 Ghr-LI 峰，其洗脱位置与合成去酰化生长素释放肽相同。这些结果表明，大多数循环的酰化生长素释放肽与较大的分子结合，而去酰化生长素释放肽作为游离肽循环。测量特定形式的生长素释放肽的测定可能比检测酰化和去酰化形式的测定更有助于确定其生理作用。
Ghrelin is a gastric peptide hormone that has an important role in appetite control and GH release. Circulating ghrelin levels are inversely correlated with body mass index and postprandially suppressed. However, the molecular form of circulating ghrelin has not been fully characterized. We studied circulating ghrelin-like immunoreactivity (Ghr-LI) using three RIAs: one specific for only the active, acylated ghrelin (antibody G0-1) and the other two detecting both active and inactive, des-acylated ghrelin (antibody SC and the commercially available Phoenix Pharmaceuticals assay). Plasma ghrelin levels were measured in healthy subjects after a test breakfast (n = 8). Ghr-LI detected by SC and the commercial assay fell significantly at 90 and 120 min post meal (P < 0.01). G0-1 Ghr-LI decreased significantly at 30 min (P < 0.05) post meal and had returned to basal levels at 90 min. Gel permeation chromatography identified three Ghr-LI peaks in plasma. TwoG0-1 Ghr-LI peaks with a molecular weight much larger than ghrelin peptide were detected. Only one Ghr-LI peak was detected by the SC and commercial RIA, at the same elution position as synthetic des-acylated ghrelin. These results suggest that the majority of circulating acylated ghrelin is bound to larger molecules, whereas des-acylated ghrelin circulates as free peptide. Assays measuring specific forms of ghrelin may be more useful in determining its physiological role than those that detect both acylated and des-acylated forms.